TY - JOUR AU - Almádi, G. AU - MacG., Dawson R.J. AU - Domokos, Gábor AU - Regős, Krisztina TI - On Equilibria of Tetrahedra JF - MATHEMATICAL INTELLIGENCER J2 - MATH INTELL PY - 2024 SN - 0343-6993 DO - 10.1007/s00283-023-10294-2 UR - https://m2.mtmt.hu/api/publication/34168012 ID - 34168012 N1 - HUN-REN-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Műegyetem Rakpart 1-3., Budapest, 1111, Hungary Department of Mathematics and Computing Science, Saint Mary’s University, Halifax, NS B3H 3C3, Canada Department of Morphology and Geometric Modeling and ELKH-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Műegyetem Rakpart 1-3., Budapest, 1111, Hungary Export Date: 2 October 2023 Correspondence Address: Almádi, G.; HUN-REN-BME Morphodynamics Research Group, Műegyetem Rakpart 1-3., Hungary; email: gergo.almadi14@gmail.com LA - English DB - MTMT ER - TY - JOUR AU - Basit, Bushra AU - Lángi, Zsolt TI - Dowker-type theorems for disk-polygons in normed planes JF - DISCRETE MATHEMATICS J2 - DISCRETE MATH VL - 347 PY - 2024 IS - 6 PG - 15 SN - 0012-365X DO - 10.1016/j.disc.2024.114019 UR - https://m2.mtmt.hu/api/publication/34792456 ID - 34792456 LA - English DB - MTMT ER - TY - JOUR AU - Basit, Bushra AU - Lángi, Zsolt TI - On monohedral tilings of a regular polygon JF - AEQUATIONES MATHEMATICAE J2 - AEQUATIONES MATH VL - 98 PY - 2024 IS - 2 SP - 535 EP - 555 PG - 21 SN - 0001-9054 DO - 10.1007/s00010-023-00973-y UR - https://m2.mtmt.hu/api/publication/34069754 ID - 34069754 N1 - Correspondence Address: Lángi, Z.; Department of Algebra and Geometry, Mŭegyetem rkp. 3, Hungary; email: zlangi@math.bme.hu AB - A tiling of a topological disc by topological discs is called monohedral if all tiles are congruent. Maltby (J Comb Theory Ser A 66:40-52, 1994) characterized the monohedral tilings of a square by three topological discs. Kurusa et al. (Mediterr J Math 17:156, 2020) characterized the monohedral tilings of a circular disc by three topological discs. The aim of this note is to connect these two results by characterizing the monohedral tilings of any regular n-gon with at most three tiles for any n = 5. LA - English DB - MTMT ER - TY - JOUR AU - Bezdek, Károly AU - Lángi, Zsolt TI - From the Separable Tammes Problem to Extremal Distributions of Great Circles in the Unit Sphere JF - DISCRETE AND COMPUTATIONAL GEOMETRY J2 - DISCRETE COMPUT GEOM PY - 2024 PG - 40 SN - 0179-5376 DO - 10.1007/s00454-023-00509-w UR - https://m2.mtmt.hu/api/publication/34006049 ID - 34006049 N1 - Department of Mathematics and Statistics, University of Calgary, Calgary, Canada Department of Mathematics, University of Pannonia, Veszprém, Hungary MTA-BME Morphodynamics Research Group and Department of Geometry, Budapest University of Technology and Economics, Budapest, Hungary Export Date: 22 June 2023 Correspondence Address: Bezdek, K.; Department of Mathematics, Hungary; email: kbezdek@ucalgary.ca AB - A family of spherical caps of the 2-dimensional unit sphere S-2 is called a totally separable packing in short, a TS-packing if any two spherical caps can be separated by a great circle which is disjoint from the interior of each spherical cap in the packing. The separable Tammes problem asks for the largest density of given number of congruent spherical caps forming a TS-packing in S-2. We solve this problem up to eight spherical caps and upper bound the density of any TS-packing of congruent spherical caps in terms of their angular radius. Based on this, we show that the centered separable kissing number of unit balls in Euclidean 3-space is 8. Furthermore, we prove bounds for the maximum of the smallest inradius of the cells of the tilings generated by n > 1 great circles in S-2. Next, we prove dual bounds for TS-coverings of S-2 by congruent spherical caps. Here a covering of S-2 by spherical caps is called a totally separable covering in short, a TS-covering if there exists a tiling generated by finitely many great circles of S-2 such that the cells of the tiling are covered by pairwise distinct spherical caps of the covering. Finally, we extend some of our bounds on TS-coverings to spherical spaces of dimension > 2. LA - English DB - MTMT ER - TY - JOUR AU - Cao, Siwen AU - Sipos, András Árpád TI - About Measuring the Stress Intensity Factor of Cracks in Curved, Brittle Shells JF - FRATTURA ED INTEGRITA STRUTTURALE J2 - FRATTURA INTEGR STRUTT VL - 18 PY - 2024 IS - 69 SP - 1 EP - 17 PG - 17 SN - 1971-8993 DO - 10.3221/IGF-ESIS.69.01 UR - https://m2.mtmt.hu/api/publication/34788249 ID - 34788249 AB - Most techniques of measuring the stress intensity factor (SIF) in the cracking process assume a crack in a planar medium. Currently, there is no effective approach for curved brittle shells, particularly for non-developable cases, i.e., shapes with non-vanishing Gaussian curvature. This paper introduces a novel approach to obtaining material properties related to fracture by experimentally observing weakly curved surfaces. Based on the DIC record of the displacement field around the crack tip, the truncated Williams expansion is fitted to the data adjusted according to the shallow shell equations. The convergence properties of the method are investigated by comparing experimental data of PMMA cylinders to theoretical and numerical predictions. The applicability of the technique to non-developable surfaces is verified. It is demonstrated that robust convergence requires the number of terms in the Williams expansion exceeding 6. For different geometries, the ratio of the data selection radius and the length of the crack should exceed 0.3. LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - Regős, Krisztina TI - A discrete time evolution model for fracture networks JF - CENTRAL EUROPEAN JOURNAL OF OPERATIONS RESEARCH J2 - CEJOR VL - 32 PY - 2024 SP - 83 EP - 94 PG - 12 SN - 1435-246X DO - 10.1007/s10100-022-00838-w UR - https://m2.mtmt.hu/api/publication/33578682 ID - 33578682 N1 - The support of the NKFIH Hungarian Research Fund Grant 134199 and of the NKFIHFundTKP2021BME-NVA,carried out at the Budapest University of Technology and Economics, is kindly acknowledged. Krisztina Reg˝os: This research has been supported by the program ÚNKP-22-3 by ITM and NKFIH. The gift representing the Albrecht Science Fellowship is gratefully appreciated. AB - We examine geological crack patterns using the mean field theory of convex mosaics. We assign the pair \left({\overline{n } }^{*},{\overline{v } }^{*}\right) n ¯ ∗ , v ¯ ∗ of average corner degrees (Domokos et al. in A two-vertex theorem for normal tilings. Aequat Math https://doi.org/10.1007/s00010-022-00888-0 , 2022) to each crack pattern and we define two local, random evolutionary steps R 0 and R 1 , corresponding to secondary fracture and rearrangement of cracks, respectively. Random sequences of these steps result in trajectories on the \left({\overline{n } }^{*},{\overline{v } }^{*}\right) n ¯ ∗ , v ¯ ∗ plane. We prove the existence of limit points for several types of trajectories. Also, we prove that cell density \overline{\rho }= \frac{{\overline{v } }^{*}}{{\overline{n } }^{*}} ρ ¯ = v ¯ ∗ n ¯ ∗ increases monotonically under any admissible trajectory. LA - English DB - MTMT ER - TY - JOUR AU - Juhász, Károly Péter AU - Schaul, Péter AU - Veres, Boglárka TI - Numerical and experimental investigation on synthetic macrofiber-reinforced concrete manhole exposed to railway loads JF - Case Studies in Construction Materials J2 - CASE STUD CONSTR MAT VL - 20 PY - 2024 PG - 25 SN - 2214-5095 DO - 10.1016/j.cscm.2024.e03093 UR - https://m2.mtmt.hu/api/publication/34785837 ID - 34785837 N1 - Budapest University of Technology and Economics, Department of Mechanics, Materials and Structures, Műegyetem rakpart 1-3, Budapest, 1111, Hungary Budapest University of Technology and Economics, Department of Construction Materials and Technologies, Műegyetem rakpart 1-3, Budapest, 1111, Hungary Kodolányi János University, Business Administration and Management, Rákóczi utca 25, Székesfehérvár, 8000, Hungary JKP STATIC Ltd, Budapest, Hungary Export Date: 12 April 2024 Correspondence Address: Juhász, P.K.; JKP STATIC Ltd, Reitter Ferenc utca 100 B/2/4, Hungary; email: office@jkp.hu AB - The refurbishment of railway lines and the installation of new tracks necessitate the construction of numerous concrete manholes; therefore, the optimization of manholes should be investigated. To this end, the use of innovative materials in addition to advanced design methods with realistic modeling is required. In the case of conservatively designed structures, there exists the possibility of redesigning the structure utilizing suitable fiber-reinforced concrete (FRC) only. The main advantage of synthetic macrofibers over steel is their complete corrosion resistance, which is essential in corrosive environments. Other advantages include their low carbon footprint, reduced construction time, and cost-effectiveness. This paper outlines the optimization process for a conventional cast-in-situ concrete manhole. The imperative for a monolithic construction system stems from the diverse geometries and distinct designs of individual pipe culverts, compounded by the often-challenging accessibility of installation sites. In the optimization phase, synthetic macrofiber reinforcement replaced conventional reinforcing steel bars, using advanced finite element analysis (FEA). The design was not conducted on an equivalent basis, resulting in potential variations in the load-carrying capacity between reinforced concrete (RC) and FRC manholes. Nevertheless, both are deemed suitable for the specified loads. The conventional design method used for RC and the advanced finite element design method used for FRC were scrutinized, taking into account the existing standard environment. Subsequently, a real-scale test was conducted to validate the calculations. Carbon footprint analyses were performed for both the original and proposed solutions, and the results were compared. The solution obtained in this study is unique and pioneering in terms of both the calculation method and the structural design, and the CO2 calculations validate its necessity. © 2024 The Authors LA - English DB - MTMT ER - TY - JOUR AU - Ludmány, Balázs AU - Lángi, Zsolt AU - Domokos, Gábor TI - Morse–Smale complexes on convex polyhedra JF - PERIODICA MATHEMATICA HUNGARICA J2 - PERIOD MATH HUNG PY - 2024 SN - 0031-5303 UR - https://m2.mtmt.hu/api/publication/34550819 ID - 34550819 N1 - Elfogadott, szerkesztés alatt AB - Motivated by applications in geomorphology, the aim of this paper is to extend Morse–Smale theory from smooth functions to the radial distance function (measured from an internal point), defining a convex polyhedron in 3-dimensional Euclidean space. The resulting polyhedral Morse–Smale complex may be regarded, on one hand, as a generalization of the Morse–Smale complex of the smooth radial distance function defining a smooth, convex body, on the other hand, it could be also regarded as a generalization of the Morse–Smale complex of the piecewise linear parallel distance function (measured from a plane), defining a polyhedral surface. Beyond similarities, our paper also highlights the marked differences between these three problems and it also relates our theory to other methods. Our work includes the design, implementation and testing of an explicit algorithm computing the Morse–Smale complex on a convex polyhedron. LA - English DB - MTMT ER - TY - JOUR AU - Nemessányi, Cecília AU - Pluzsik, Anikó TI - Effect of Bonding Type on the Failure of Reinforced Concrete Beam Strengthened with In-Situ High Performance Fibre Reinforced Concrete Layer JF - ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY J2 - ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY VL - 52 PY - 2024 IS - 1-2 SP - 49 EP - 73 PG - 25 SN - 0013-9661 DO - 10.1556/096.2024.00113 UR - https://m2.mtmt.hu/api/publication/34751447 ID - 34751447 N1 - Export Date: 22 March 2024 AB - High performance fibre reinforced concrete (HPFRC) materials with tensile hardening behaviour can effectively be used for strengthening reinforced concrete beams. A perfect bond between the original and the reinforcing layer cannot be formed, the load-bearing capacity and ductility of the strengthened beam can significantly be affected by the interfacial bond strength between the contacting surfaces. In this paper, beam retrofitting with cast in-situ strengthening type is examined. The purpose of this experimental study is to investigate the impact of the different bond types on the load-bearing capacity, ductility, and failure mode of the strengthened beams in the case of cast in-situ strengthening. Twenty-four beam tests were performed with untreated and rough surfaced beams, with or without connecting elements. The effect of the bond type proved to be significant regarding the failure mode in the case of compression side strengthening, stronger bond resulted in higher load bearing capacity and ductility, too. When tensile side reinforcement was investigated no average increment was experienced in the maximal force and ductility due to the stronger bond. Based on the results, it can be concluded that the generally applied analytical models that assume perfect connection may lead to exaggerated results in the case of a compressed side HPC-strengthened beam. Therefore, it is necessary to develop a model that considers the effect of the imperfect bond. © 2024 The Authors. LA - English DB - MTMT ER - TY - JOUR AU - Páll-Gergely, Barna AU - Sipos, András Árpád AU - Harzhauser, Mathias AU - Örstan, Aydın AU - Winkler, Viola AU - Neubauer, Thomas A TI - Many roads to success: Alternative routes to building an economic shell in land snails JF - EVOLUTION J2 - EVOLUTION VL - 78 PY - 2024 IS - 4 SP - 778 EP - 786 PG - 9 SN - 0014-3820 DO - 10.1093/evolut/qpae018 UR - https://m2.mtmt.hu/api/publication/34542705 ID - 34542705 N1 - Funding Agency and Grant Number: Hungarian Research Fund [OTKA FK 135262, OTKA K134199]; Bolyai Research Scholarship of the Hungarian Academy of Sciences; National Research, Development, and Innovation Fund of Hungary [TKP2021-NVA-02] Funding text: This study was supported by the Hungarian Research Fund grants OTKA FK 135262 (B.P.G.) and OTKA K134199 (A.A.S.), the Bolyai Research Scholarship of the Hungarian Academy of Sciences for B.P.G., and the National Research, Development, and Innovation Fund of Hungary under grant TKP2021-NVA-02 (A.A.S.). AB - Land snails exhibit an extraordinary variety of shell shapes. The way shells are constructed underlie biological and mechanical constraints that vary across gastropod clades. Here, we quantify shell geometry of the two largest groups, Stylommatophora and Cyclophoroidea, to assess the potential causes for variation in shell shape and its relative frequency. Based on µCT scans, we estimate material efficiency through 2D- and 3D-generalisations of the isoperimetric ratio, quantifying the ratios between area and perimeter of whorl cross-sections (2D) and shell volume and surface (3D), respectively. We find that stylommatophorans optimise material usage through whorl overlap, which may have promoted the diversification of flat-shelled species. Cyclophoroids are bound to a circular cross-section because of their operculum; flat shells are comparatively rare. Both groups show similar solutions for tall shells, where local geometry has a smaller effect because of the double overlap between previous and current whorls. Our results suggest that material efficiency is a driving factor in the selection of shell geometry. Essentially, the evolutionary success of Stylommatophora likely roots in their higher flexibility to produce an economic shell. LA - English DB - MTMT ER - TY - JOUR AU - Sipos, András Árpád TI - About the number of hinges at failure of semicircular and pointed masonry arches JF - MATHEMATICS AND MECHANICS OF SOLIDS J2 - MATH MECH SOLIDS PY - 2024 PG - 11 SN - 1081-2865 DO - 10.1177/10812865231196796 UR - https://m2.mtmt.hu/api/publication/34166610 ID - 34166610 N1 - Department of Morphology and Geometric Modeling, Budapest University of Technology and Economics, Budapest, Hungary MTA-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Budapest, Hungary Export Date: 19 October 2023 Correspondence Address: Sipos, A.A.; Department of Morphology and Geometric Modeling, Hungary; email: siposa@eik.bme.hu AB - The collapse of masonry arches under static loads mainly occurs because some voussoir interfaces open and form hinges and eventually transform the structure into a mechanism. There is an interest in the maximum number of concurrent hinges at a given arch geometry and stereotomy, which latter refers to the cutting pattern of the voussoirs. This paper applies the governing equations of a geometrically exact rod to thrust line analysis while it adopts the Heymanian assumptions. With the new model, the number of concurrent hinges can be investigated in an organized and predictive manner generalizing the numerical and analytical results of the literature. Specifically, this paper proves that the number of hinges for a symmetric, circular pointed arch loaded by self-weight cannot exceed seven in the cases of vertical stereotomy and constant thickness in the vertical or normal directions. The maximum number of hinges is also seven for an arch with constant thickness and radial stereotomy. LA - English DB - MTMT ER - TY - JOUR AU - Bálint, Péter AU - Domokos, Gábor AU - Regős, Krisztina TI - An evolution model for polygonal tessellations as models for crack networks and other natural patterns JF - JOURNAL OF STATISTICAL PHYSICS J2 - J STAT PHYS VL - 190 PY - 2023 IS - 8 PG - 30 SN - 0022-4715 DO - 10.1007/s10955-023-03146-y UR - https://m2.mtmt.hu/api/publication/33665427 ID - 33665427 N1 - Funding Agency and Grant Number: Budapest University of Technology and Economics Funding text: Open access funding provided by Budapest University of Technology and Economics. The research of the authors was supported by several funding institutions. Details are provided on the title page. AB - We introduce and study a general framework for modeling the evolution of crack networks. The evolution steps are triggered by exponential clocks corresponding to local micro-events, and thus reflect the state of the pattern. In an appropriate simultaneous limit of pattern domain tending to infinity and time step tending to zero, a continuous time model, specifically a system of ODE is derived that describes the dynamics of averaged quantities. In comparison with the previous, discrete time model, studied recently by two of the present three authors, this approach has several advantages. In particular, the emergence of non-physical solutions characteristic to the discrete time model is ruled out in the relevant nonlinear version of the new model. We also comment on the possibilities of studying further types of pattern formation phenomena based on the introduced general framework. LA - English DB - MTMT ER - TY - CHAP AU - Bertoni, Duccio AU - Di Renzone, Gabriele AU - Domokos, Gábor AU - Favaretto, Chiara AU - Pozzebon, Alessandro AU - Sarti, Giovanni TI - A Technique for the Measurement of the Morphological Evolution of Marine Pebbles T2 - 2023 IEEE International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea) PB - IEEE CY - Piscataway (NJ) SN - 9798350340662 PY - 2023 SP - 433 EP - 438 PG - 6 DO - 10.1109/MetroSea58055.2023.10317284 UR - https://m2.mtmt.hu/api/publication/34383912 ID - 34383912 N1 - University of Pisa, Department of Earth Sciences, Pisa, Italy University of Pisa, Department of Information Engineering, Pisa, Italy Budapest University of Technology and Economics, Department of Morphology and Geometric Modeling, HUN-REN-BME Morphodynamics Research Group, Budapest, Hungary University of Padova, Department of Civil, Environmental and Architectural Engineering, Padova, Italy University of Padova, Department of Information Engineering, Padova, Italy Conference code: 194563 Export Date: 22 December 2023 Correspondence Address: Bertoni, D.; University of Pisa, Italy; email: duccio.bertoni@unipi.it LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - Kovács, Flórián TI - Conway’s Spiral and a Discrete Gömböc with 21 Point Masses JF - AMERICAN MATHEMATICAL MONTHLY J2 - AM MATH MON VL - 130 PY - 2023 IS - 9 SP - 795 EP - 807 PG - 13 SN - 0002-9890 DO - 10.1080/00029890.2023.2241336 UR - https://m2.mtmt.hu/api/publication/34108939 ID - 34108939 N1 - Hungarian Academy of Sciences, Hungary Department of Morphology and Geometric Modeling and ELKH-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Budapest, H-1111, Hungary Budapest University of Technology and Economics, Hungary Department of Structural Mechanics and ELKH-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Budapest, H-1111, Hungary Export Date: 24 August 2023 LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - Lángi, Zsolt AU - Várkonyi, Péter László TI - A characterization of the symmetry groups of mono-monostatic convex bodies JF - MONATSHEFTE FUR MATHEMATIK J2 - MONATSH MATH VL - 201 PY - 2023 IS - 3 SP - 703 EP - 724 PG - 22 SN - 0026-9255 DO - 10.1007/s00605-023-01847-w UR - https://m2.mtmt.hu/api/publication/33742876 ID - 33742876 N1 - ELKH-BME Morphodynamics Research Group, Budapest University of Technology, Műegyetem rakpart 1-3, Budapest, 1111, Hungary Department of Morphology and Geometric Modeling, Budapest University of Technology and Economics, Budapest, H-1111, Hungary Department of Geometry, Budapest University of Technology, Egry József utca 1, Budapest, 1111, Hungary Department of Mechanics, Materials and Structures, Budapest University of Technology, Műegyetem rakpart 1-3, Budapest, 1111, Hungary Export Date: 11 April 2023 Correspondence Address: Lángi, Z.; Department of Geometry, Egry József utca 1, Hungary; email: zlangi@math.bme.hu AB - Answering a question of Conway and Guy (SIAM Rev. 11:78-82, 1969), Langi (Bull. Lond. Math. Soc. 54: 501-516, 2022) proved the existence of a monostable polyhedron with n-fold rotational symmetry for any n = 3, and arbitrarily close to a Euclidean ball. In this paper we strengthen this result by characterizing the possible symmetry groups of all mono-monostatic smooth convex bodies and convex polyhedra. Our result also answers a stronger version of the question of Conway and Guy, asked in the above paper of Langi. LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - G. Horváth, Ákos AU - Regős, Krisztina TI - A two-vertex theorem for normal tilings JF - AEQUATIONES MATHEMATICAE J2 - AEQUATIONES MATH VL - 97 PY - 2023 SP - 185 EP - 197 PG - 13 SN - 0001-9054 DO - 10.1007/s00010-022-00888-0 UR - https://m2.mtmt.hu/api/publication/32864242 ID - 32864242 N1 - Funding Agency and Grant Number: NKFIH Hungarian Research Fund [134199]; NKFIH Fund TKP2021 BME-NVA; ITM [UNKP-22-3]; NKFIH Funding text: Gabor Domokos and Krisztina Regos: The support of the NKFIH Hungarian Research Fund grant 134199 and of the NKFIH Fund TKP2021 BME-NVA, carried out at the Budapest University of Technology and Economics, is kindly acknowledged. Krisztina Regos: This research has been supported by the program UNKP-22-3 by ITM and NKFIH. The gift representing the Albrecht Science Fellowship is gratefully appreciated. LA - English DB - MTMT ER - TY - JOUR AU - Erdélyiné Tóth, Mária AU - Pluzsik, Anikó TI - Size Effect of Synthetic Fibre Reinforced Concrete - Investigation using a Semi-Discrete Analytical Beam Model JF - ARCHITECTURE CIVIL ENGINEERING ENVIRONMENT J2 - ARCHIT CIV ENG ENV VL - 16 PY - 2023 IS - 3 SP - 117 EP - 129 PG - 13 SN - 1899-0142 DO - 10.2478/acee-2023-0039 UR - https://m2.mtmt.hu/api/publication/34342487 ID - 34342487 AB - The size effect is a well-known characteristic of concrete structures. However, in the case of fibre-reinforced concrete (FRC), this issue is not thoroughly explored. Most design recommendations of FRC neglect the size effect or handle the behaviour of FRC structures in case of different structural sizes similar to plain concrete structures (assuming FRC is a homogeneous material). The aim of this paper is to show that the size effect of FRC can be divided, the share of the concrete matrix and the fibres in the size-dependent properties is separable. For the size effect research fifteen synthetic macro fibre reinforced concrete and six plain concrete beam specimens were prepared and tested in three different sizes and then evaluated with the semi-discrete analytical (SDA) model. The analysis of the experimental specimens has shown that the size effect significantly influences the concrete material in the case of FRC with softening material behaviour, but the residual loadbearing capacity which mainly arise from the local bridging effect of fibres is essentially independent of the structural size. It is also shown in this paper that the two defining parameters of the SDA model is independent of the structural size, so the model provides an excellent tool in case of the design of real-sized FRC structures. LA - English DB - MTMT ER - TY - JOUR AU - Gáspár, Orsolya AU - Kis, Alexandra E. TI - The Invisible Beauty of the Zeiss-Dywidag Domes: Topology Optimization of the Triangulated Rebar Grids JF - INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE J2 - INT J ARCHIT HERIT PY - 2023 PG - 22 SN - 1558-3058 DO - 10.1080/15583058.2023.2217659 UR - https://m2.mtmt.hu/api/publication/34048901 ID - 34048901 N1 - Funding Agency and Grant Number: ~Nemzeti Kutatasi Fejlesztesi es Innovacios Hivatal [UNKP-21-4-II-BME-181] Funding text: The work was supported by the~Nemzeti Kutatasi Fejlesztesi es Innovacios Hivatal [UNKP-21-4-II-BME-181]. AB - The Zeiss-Dywidag system was a pioneer in the history of thin concrete shells, which impacted and advanced theory and praxis worldwide. This study explains its relevance for the history of gridshells: the first ever built Zeiss-Dywidag dome started out as a geodesic gridshell, sprayed over by concrete. Walther Bauersfeld abandoned his own ingenious design for the first Planetarium in Jena in favour of a lamella-type topology for the equally self-bearing reinforcing grid of the later Zeiss-Dywidag domes. We reconstruct the optimization of the geometry and tessellation of the first built example of the latter, the Schott dome, and suggest possible motivations for the change. Bauersfeld's strikingly advanced theory of equivalent membrane shells, which played an essential role in the process, is published here for the first time. The significance of a unique benchmarking parameter, the so-called bar density (D-value), introduced by Bauersfeld is investigated. Its applicability to assess geometric fitness is assessed by a comparative study of selected grid topologies and geometries. LA - English DB - MTMT ER - TY - JOUR AU - Gáspár, Orsolya AU - Sajtos, István AU - Sipos, András Árpád TI - Multi-Hinge Failure Mechanisms of Masonry Arches Subject to Self-Weight as Derived from Minimum Thickness Analysis JF - INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE J2 - INT J ARCHIT HERIT VL - 17 PY - 2023 IS - 12 SP - 1921 EP - 1949 PG - 29 SN - 1558-3058 DO - 10.1080/15583058.2022.2084702 UR - https://m2.mtmt.hu/api/publication/32911089 ID - 32911089 N1 - Funding Agency and Grant Number: NKFIH Grant [124859]; National Research, Development, and Innovation Fund of Hungary [TKP2021-NVA-02] Funding text: The research was supported by the NKFIH Grant 124859 and by the National Research, Development, and Innovation Fund of Hungary under Grant TKP2021-NVA-02. AB - The present study investigates the relation between the optimal geometry (quantified via the minimum thickness) and the number of concurrent hinges at the masonry arch’s limit state. The Heymanian assumptions regarding material behavior are adopted, and only constant thickness arches subject to static (i.e., self-weight) loading are considered. First, the only numerically verified completeness of the failure mode types (including 6 and even 7 hinges) of gothic arches is analytically proven. Next, it is investigated whether a higher number of hinges can concurrently occur for arbitrary, symmetric concave arches. A numerical procedure is presented which generates suitable arch geometries corresponding to a k-hinge mechanism, where k is an arbitrary odd integer not smaller than 5. For the generated class of arches, a higher number of concurrent hinges leads to lower minimum thickness values. However, it is explicitly proven that a higher number of hinges is not necessary for lower minimum thickness values. A small database about the geometry of the transversal arches of English and French medieval gothic cathedrals concludes the first part to allow comparison with the derived results. In the second part of the paper, existing literature results on the limit state analysis of gothic arches are extended by the effect of stereotomy on the failure mode type and minimum thickness value. LA - English DB - MTMT ER - TY - JOUR AU - Guerra Riaño, Andres Felipe AU - Várkonyi, Péter László TI - Form-finding using the Force Density Method: Existence of solutions, singularities, and an analogy to electric circuits JF - INTERNATIONAL JOURNAL OF SPACE STRUCTURES J2 - INT J SPACE STRUCT VL - 38 PY - 2023 IS - 4 SP - 302 EP - 326 PG - 25 SN - 0956-0599 DO - 10.1177/09560599231207042 UR - https://m2.mtmt.hu/api/publication/34005757 ID - 34005757 N1 - Export Date: 30 November 2023 CODEN: ISSTE Correspondence Address: Guerra Riaño, A.F.; Department of Mechanics, Hungary; email: guerra.andres@edu.bme.hu AB - The Force Density Method is the oldest computational method for form-finding of funicular structures. The method is based on solving a linear system of equilibrium equations. Linearity ensures existence and uniqueness of the solution, provided that the coefficient matrix is non-singular. In the opposite case, the method often fails to deliver a feasible solution. In this study, we highlight a mathematical analogy between force density networks and electric circuits. Motivated by standard reduction steps in networks of electric resistors, inductors, or capacitors, we develop a new sequential reduction technique applicable to networks of force density elements. Network reduction enables analytic detection of singularity in many cases. Several examples illustrate the feasibility of the proposed singularity test, furthermore the role of singularities in classification of emergent structural forms is discussed. LA - English DB - MTMT ER - TY - BOOK AU - Gyetvainé Balogh, Ágnes AU - Frey, György Péter AU - Kalmár, Miklós AU - Kiss, Zsuzsanna Emília AU - Zsembery, Ákos ED - Armuth, Miklós ED - Lőrinczi, Zsuzsa TI - Műegyetem - a történeti Campus / The historic Campus. A Budapesti Műszaki és Gazdaságtudományi Egyetem történeti Campusa / The historic Campus of the Budapest University of Technology and Economics TS - A Budapesti Műszaki és Gazdaságtudományi Egyetem történeti Campusa / The historic Campus of the Budapest University of Technology and Economics ET - 2 PB - Budapesti Műszaki és Gazdaságtudományi Egyetem CY - Budapest PY - 2023 SP - 280 SN - 9789634217848 UR - https://m2.mtmt.hu/api/publication/34129652 ID - 34129652 LA - English DB - MTMT ER - TY - JOUR AU - Joós, Antal AU - Lángi, Zsolt TI - Isoperimetric problems for zonotopes JF - MATHEMATIKA J2 - MATHEMATIKA VL - 69 PY - 2023 IS - 2 SP - 508 EP - 534 PG - 27 SN - 0025-5793 DO - 10.1112/mtk.12191 UR - https://m2.mtmt.hu/api/publication/33734944 ID - 33734944 N1 - Funding Agency and Grant Number: BME Water Sciences & Disaster Prevention TKP2020 Institution Excellence Subprogram [TKP2020BME-IKA-VIZ]; NKFIH [K134199] Funding text: BME Water Sciences & Disaster Prevention TKP2020 Institution Excellence Subprogram, Grant/Award Number: TKP2020BME-IKA-VIZ; NKFIH, Grant/Award Number: K134199 AB - Shephard (Canad. J. Math. 26 (1974), 302-321) proved a decomposition theorem for zonotopes yielding a simple formula for their volume. In this note, we prove a generalization of this theorem yielding similar formulae for their intrinsic volumes. We use this result to investigate geometric extremum problems for zonotopes generated by a given number of segments. In particular, we solve isoperimetric problems for d-dimensional zonotopes generated by d or d+1$d+1$ segments, and give asymptotic estimates for the solutions of similar problems for zonotopes generated by sufficiently many segments. In addition, we present applications of our results to the l(1) polarization problem on the unit sphere and to a vector-valued Maclaurin inequality conjectured by Brazitikos and McIntyre in 2021. LA - English DB - MTMT ER - TY - JOUR AU - Kadlicskó, Máté AU - Lángi, Zsolt TI - On generalized Minkowski arrangements JF - ARS MATHEMATICA CONTEMPORANEA J2 - ARS MATH CONTEMPOR VL - 23 PY - 2023 IS - 1 PG - 18 SN - 1855-3966 DO - 10.26493/1855-3974.2550.d96 UR - https://m2.mtmt.hu/api/publication/32669283 ID - 32669283 AB - The concept of a Minkowski arrangement was introduced by Fejes Tóth in 1965 as a family of centrally symmetric convex bodies with the property that no member of the family contains the center of any other member in its interior. This notion was generalized by Fejes Tóth in 1967, who called a family of centrally symmetric convex bodies a generalized Minkowski arrangement of order μ for some 0 < μ < 1 if no member K of the family overlaps the homothetic copy of any other member K′ with ratio μ and with the same center as K′. In this note we prove a sharp upper bound on the total area of the elements of a generalized Minkowski arrangement of order μ of finitely many circular disks in the Euclidean plane. This result is a common generalization of a similar result of Fejes Tóth for Minkowski arrangements of circular disks, and a result of Böröczky and Szabó about the maximum density of a generalized Minkowski arrangement of circular disks in the plane. In addition, we give a sharp upper bound on the density of a generalized Minkowski arrangement of homothetic copies of a centrally symmetric convex body. LA - English DB - MTMT ER - TY - JOUR AU - Preißinger, Katharina AU - Kézsmárki, István AU - Török, János TI - An automated neural network-based stage-specific malaria detection software using dimension reduction: The malaria microscopy classifier JF - METHODSX J2 - METHODSX VL - 10 PY - 2023 PG - 11 SN - 2215-0161 DO - 10.1016/j.mex.2023.102189 UR - https://m2.mtmt.hu/api/publication/33780709 ID - 33780709 N1 - Department of Applied Biotechnology and Food Sciences, BME, Budapest, 1111, Hungary Research Center for Natural Sciences, Institute of Enzymology, Budapest, 1111, Hungary Department of Physics, BME, Budapest, 1111, Hungary Department of Experimental Physics V, University of Augsburg, Augsburg, 86159, Germany Department of Theoretical Physics, Institute of Physics, BME, Műegyetem rkp. 3, Budapest, H-1111, Hungary MTA-BME Morphodynamics Research Group, BME, Budapest, 1111, Hungary Export Date: 5 May 2023 Correspondence Address: Katharina, P.; Department of Experimental Physics V, Germany; email: katharina.preissinger@physik.uni-augsburg.de LA - English DB - MTMT ER - TY - JOUR AU - Ludmány, Balázs AU - Ignacio, Pérez-Rey AU - Domokos, Gábor AU - Mauro, Muñiz-Menéndez AU - Leandro R., Alejano AU - Sipos, András Árpád TI - A New Insight into the Stability of Precariously Balanced Rocks JF - ROCK MECHANICS AND ROCK ENGINEERING J2 - ROCK MECH ROCK ENG VL - 56 PY - 2023 IS - 5 SP - 3539 EP - 3550 PG - 12 SN - 0723-2632 DO - 10.1007/s00603-023-03233-2 UR - https://m2.mtmt.hu/api/publication/33608779 ID - 33608779 N1 - MTA-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Budapest, Hungary Department of Morphology and Geometric Modeling, Budapest University of Technology and Economics, Budapest, Hungary Department of Natural Resources and Environmental Engineering, GESSMIN Group, CINTECX, University of Vigo, Vigo, Spain Laboratorio de Geotecnia, CEDEX, Madrid, Spain CODEN: RMRED Correspondence Address: Sipos, A.Á.; MTA-BME Morphodynamics Research Group, Hungary; email: siposa@eik.bme.hu AB - Large granitic boulders resting on steep slopes represent considerable safety hazards that largely depend on the location of the contact surface characterized by the impression d , denoting the parallel distance between the contact surface and the original rock surface. On the other hand, this impression reflecting the often convex nature of the contact between boulders and resting platforms, cannot be measured precisely, so Factors of Safety (FoS) computed with this input may have significant uncertainties. Using geometric 3D analysis, here, we present the concept of computing FoS as a function of the impression d , admitting a much more reliable estimate of the actual hazards. Beyond introducing the FoS functions, we also identify all failure modes, some of which have not yet been investigated. We compute the FoS functions for the boulder Pena do Equilibrio , located in Spain. Our computations for FoS against sliding match all earlier results. However, we also compute FoS against toppling and against torsion and show that the latter may be critical. Since our methods are general, this suggests that torsion phenomena, which have been scarcely studied so far, may be relevant to analyze the stability of other natural rock boulders. LA - English DB - MTMT ER - TY - JOUR AU - Michel, Sébastien AU - Sipos, András Árpád TI - Fragmentation of inflated elastic brittle rings: Emergence of the quasi-equidistant spacing of cracks JF - JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS J2 - J MECH PHYS SOLIDS VL - 179 PY - 2023 PG - 17 SN - 0022-5096 DO - 10.1016/j.jmps.2023.105372 UR - https://m2.mtmt.hu/api/publication/34060364 ID - 34060364 N1 - Export Date: 14 August 2023 CODEN: JMPSA Correspondence Address: Michel, S.; Department of Morphology and Geometric Modeling, Hungary; email: sebastien.michel@edu.bme.hu AB - The order of appearance and the position of meridional cracks in brittle domes is a delicate question of mechanics. This paper investigates a dimension-reduced model, a pressurized brittle ring constrained to the plane, to show that a simple, deterministic approach based on the Griffith theory of fracture predicts quasi-equidistant, i.e., close to an equal spacing of the emerging cracks. It is also demonstrated that the order of emergence is significantly affected by the variation of the in-plane elastic support as well the bending rigidity of the ring. In the model, the energy minimization is first recast into a sequence of coupled boundary value problems. The relationship between the mechanical model and geometric properties of the emerging pattern is studied numerically. The pattern is shown to be driven by elaborate co-dimension one bifurcations and by the requirement of global energy minimization. LA - English DB - MTMT ER - TY - JOUR AU - Papp, D AU - Regős, Krisztina AU - Domokos, Gábor AU - Bozóki, Sándor TI - The smallest mono-unstable convex polyhedron with point masses has 8 faces and 11 vertices JF - EUROPEAN JOURNAL OF OPERATIONAL RESEARCH J2 - EJOR VL - 310 PY - 2023 IS - 2 SP - 511 EP - 517 PG - 7 SN - 0377-2217 DO - 10.1016/j.ejor.2023.04.028 UR - https://m2.mtmt.hu/api/publication/33771781 ID - 33771781 N1 - Funding Agency and Grant Number: National Science Foundation [DMS-1847865]; NKFIH Hungarian Research Fund [134199]; ITM; NKFIH; NRDIO grant [TKP2021-NKTA-01] Funding text: This material is based upon work supported by the National Science Foundation under Grant no. DMS-1847865 . GD, KR: The support of the NKFIH Hungarian Research Fund grant 134199 and of the NKFIH Fund TKP2021 BME-NVA, carried out at the Budapest University of Technology and Economics, is kindly acknowledged. KR: This research has been supported by the program UNKP-22-3 by ITM and NKFIH. The gift representing the Albrecht Science Fellowship is gratefully appreciated. SB: The research has been supported in part by the TKP2021-NKTA-01 NRDIO grant. LA - English DB - MTMT ER - TY - JOUR AU - Regős, Krisztina AU - Pawlak, R. AU - Wang, X. AU - Meyer, E. AU - Decurtins, S. AU - Domokos, Gábor AU - Novoselov, K.S. AU - Liu, S.-X. AU - Aschauer, U. TI - Polygonal tessellations as predictive models of molecular monolayers JF - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA J2 - P NATL ACAD SCI USA VL - 120 PY - 2023 IS - 16 SN - 0027-8424 DO - 10.1073/pnas.2300049120 UR - https://m2.mtmt.hu/api/publication/33879799 ID - 33879799 N1 - Department of Morphology and Geometric Modeling, Budapest University of Technology and Economics, Budapest, H-1111, Hungary Morphodynamics Research Group, Eötvös Lóránd Research Network and Budapest University of Technology and Economics, Budapest, H-1111, Hungary Department of Physics, University of Basel, Basel, 4056, Switzerland Department of Chemistry, Biochemistry and Pharmacy, University of Bern, Bern, 3012, Switzerland Institute for Functional Intelligent Materials, National University of Singapore, Singapore, 117544, Singapore Export Date: 26 May 2023 CODEN: PNASA Correspondence Address: Regős, K.; Department of Morphology and Geometric Modeling, Hungary; email: regos.kriszti@gmail.com Correspondence Address: Novoselov, K.S.; Institute for Functional Intelligent Materials, Singapore; email: kostya@manchester.ac.uk Correspondence Address: Liu, S.-X.; Department of Chemistry, Switzerland; email: shixia.liu@unibe.ch Correspondence Address: Aschauer, U.; Department of Physics, Switzerland; email: ulrich.aschauer@unibe.ch LA - English DB - MTMT ER - TY - JOUR AU - Shimada, T. AU - Ogushi, F. AU - Török, János AU - Kertész, J. AU - Kaski, K. TI - A simple model of edit activity in Wikipedia JF - PHYSICA A - STATISTICAL MECHANICS AND ITS APPLICATIONS J2 - PHYSICA A VL - 630 PY - 2023 PG - 11 SN - 0378-4371 DO - 10.1016/j.physa.2023.129253 UR - https://m2.mtmt.hu/api/publication/34192919 ID - 34192919 N1 - Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan Mathematics and Informatics Center, The University of Tokyo, Japan Center for Mathematical Modeling and Data Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan MTA-BME Morphodynamics Research Group, Department of Theoretical Physics, Budapest University of Technology and Economics, Műegyetem Rkp 3, Budapest, 1111, Hungary Department of Network and Data Science, Central European University, Vienna, Austria Aalto University, School of Science, Espoo, Finland Export Date: 13 October 2023 CODEN: PHYAD Correspondence Address: Shimada, T.; Department of Systems Innovation, 7-3-1 Hongo, Bunkyo-ku, Japan; email: shimada@sys.t.u-tokyo.ac.jp LA - English DB - MTMT ER - TY - CHAP AU - Sipos, András Árpád ED - Arnold, Martin ED - Jelenic, Gordan ED - Papa Dukic, Edita TI - On the number of congruent hinges of masonry arches at failure T2 - HFSS 2023 : International Conference on Highly Flexible Slender Structures PB - Faculty of Civil Engineering, University of Rijeka CY - Rijeka SN - 9789536953615 PY - 2023 SP - 61 EP - 62 PG - 2 UR - https://m2.mtmt.hu/api/publication/34163826 ID - 34163826 LA - English DB - MTMT ER - TY - THES AU - Sipos, András Árpád TI - Mechanikai és természeti formák elemzése: matematikai modellek a morfológiában PY - 2023 SP - 114 UR - https://m2.mtmt.hu/api/publication/34034649 ID - 34034649 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Tajta, I. AU - Dulácska, Endre TI - On the Buckling of the No-tension Material Masonry Column JF - ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY J2 - ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY VL - 51 PY - 2023 IS - 3-4 SP - 181 EP - 194 PG - 14 SN - 0013-9661 DO - 10.1556/096.2023.00095 UR - https://m2.mtmt.hu/api/publication/34139844 ID - 34139844 N1 - Export Date: 14 September 2023 Correspondence Address: Dulácska, E.; Department of Mechanics, K. II. 61, Muegyetem rkp. 3, Hungary; email: dulilonci@freemail.hu LA - English DB - MTMT ER - TY - JOUR AU - Ther, Péter Pál AU - Sajtos, István TI - Historical Shear Experiments of RC Beams in Hungary and their Effect on Change of Shear Design JF - PERIODICA POLYTECHNICA-CIVIL ENGINEERING J2 - PERIOD POLYTECH CIV ENG VL - 67 PY - 2023 IS - 3 SP - 647 EP - 658 PG - 12 SN - 0553-6626 DO - 10.3311/PPci.21433 UR - https://m2.mtmt.hu/api/publication/33721837 ID - 33721837 N1 - Funding Agency and Grant Number: National Research, Development, and Innovation Fund of Hungary [TKP2021-NVA-02] Funding text: Acknowledgment The research was supported by the National Research, Development, and Innovation Fund of Hungary under Grant TKP2021-NVA-02. It is highly appreciated and acknowledged.We want to say thank you to Dr. Visnovitz, Gy., who guided us in the world of the COMECON era. The authors highly appreciate and express their great gratitude to the Reviewers who helped improve the con-tent and quality of the paper. AB - The shear behavior is one of the most mysterious physical phenomena of an RC (reinforced concrete) beam. Many shear-transfer actions (such as dowel action, cantilever action, aggregate interlock, tension softening, etc.) affect it. Still, there is no scientific agreement on the number and the role of these phenomena.The paper investigates the historical development of these shear-transfer actions and the calculation models made from them through the glass of experimental research in the last one and half centuries in Hungary, in the context of the current international state of the art. This historical approach gives us an understanding of how the researchers and engineers of the past tried to understand the structure, and it leads us to accept that we are also on the way to understanding the shear behavior. However, the perfect model and understanding are far away from now. But are we on the right way? LA - English DB - MTMT ER - TY - JOUR AU - Várkonyi, Péter László TI - An improved Lyapunov stability test of equilibria under frictional, unilateral contact by sums of squares programming JF - IEEE TRANSACTIONS ON AUTOMATIC CONTROL J2 - IEEE T AUTOMAT CONTR PY - 2023 PG - 14 SN - 0018-9286 DO - 10.1109/TAC.2023.3333738 UR - https://m2.mtmt.hu/api/publication/34434613 ID - 34434613 N1 - Export Date: 14 December 2023 CODEN: IETAA LA - English DB - MTMT ER - TY - ART ED - Alföldi, György / Designer ED - Hauszknecht, Katalin / Designer ED - Vasáros-Lévai, Melinda / Designer AU - Armuth, Miklós AU - Takács, Lajos Gábor AU - Pataky, Rita AU - Sámson, Kinga AU - Sági, Gergely AU - Major, Zoltán AU - Müllner, Péter AU - Máthé, Dóra AU - Ferenczi, Natália AU - Kalmár, Péter AU - Hámornyik, József AU - Dr. Molnár, Bálint AU - Sütöri, Laura AU - Nemes, Bettina AU - Borbély, Áron AU - Faragó, Gergő AU - Dőry, Fruzsina AU - Fehér, Béla AU - Kelemen, László TI - BME Látogató Központ PY - 2022 UR - https://m2.mtmt.hu/api/publication/34508337 ID - 34508337 AB - A tárlat a Műegyetem K épületének aulájából nyíló látogatótérben tekinthető meg. Az érdeklődők betekintést nyerhetnek a karok tevékenységébe, megismerhetik kutatási eredményeiket, valamint neves műegyetemisták találmányaival és BME-s relikviákkal is találkozhatnak. DB - MTMT ER - TY - ART ED - Alföldi, György / Designer ED - Armuth, Miklós / Designer TI - Pecz Samu szobor talapzat , BME Központi Könytár PY - 2022 UR - https://m2.mtmt.hu/api/publication/34504981 ID - 34504981 AB - Bodó Csaba, Pecz Samu szobor, talapzata DB - MTMT ER - TY - JOUR AU - Almohammad, Sami Mezal AU - Lángi, Zsolt AU - Naszódi, Márton TI - An analogue of a theorem of Steinitz for ball polyhedra in R-3 JF - AEQUATIONES MATHEMATICAE J2 - AEQUATIONES MATH VL - 96 PY - 2022 IS - 2 SP - 403 EP - 415 PG - 13 SN - 0001-9054 DO - 10.1007/s00010-021-00815-9 UR - https://m2.mtmt.hu/api/publication/32282957 ID - 32282957 N1 - Institute of Mathematics, Loránd Eötvös University, Budapest, Hungary Department of MathematicsFaculty of Computer Science and Mathematics, University of Thi-Qar, Thi-Qar, Iraq MTA-BME Morphodynamics Research Group and Department of Geometry, Budapest University of Technology, Budapest, Hungary Department of Geometry and MTA-ELTE Lendület Combinatorial Geometry Research Group, Loránd Eötvös University, Budapest, Hungary Export Date: 13 June 2023 Correspondence Address: Naszódi, M.; Department of Geometry and MTA-ELTE Lendület Combinatorial Geometry Research Group, Hungary; email: marton.naszodi@math.elte.hu AB - Steinitz's theorem states that a graph G is the edge-graph of a 3-dimensional convex polyhedron if and only if, G is simple, plane and 3-connected. We prove an analogue of this theorem for ball polyhedra, that is, for intersections of finitely many unit balls in R-3. LA - English DB - MTMT ER - TY - JOUR AU - Antali, Máté AU - Várkonyi, Péter László TI - The Nonsmooth Dynamics of Combined Slip and Spin Motion Under Dry Friction JF - JOURNAL OF NONLINEAR SCIENCE J2 - J NONLINEAR SCI VL - 32 PY - 2022 IS - 4 SN - 0938-8974 DO - 10.1007/s00332-022-09812-x UR - https://m2.mtmt.hu/api/publication/32900821 ID - 32900821 N1 - Funding Agency and Grant Number: Szechenyi Istvan University Funding text: Open access funding provided by Szechenyi Istvan University (SZE). LA - English DB - MTMT ER - TY - CONF AU - Antali, Máté AU - Várkonyi, Péter László TI - Nonsmooth dynamics of slip and stick with a finite-sized contact area T2 - ENOC 2022: Book of abstracts PY - 2022 SP - 557 EP - 558 PG - 2 UR - https://m2.mtmt.hu/api/publication/33547135 ID - 33547135 LA - English DB - MTMT ER - TY - JOUR AU - Basit, Bushra AU - Lángi, Zsolt TI - Discrete isoperimetric problems in spaces of constant curvature JF - MATHEMATIKA J2 - MATHEMATIKA VL - 69 PY - 2022 IS - 1 SP - 33 EP - 50 PG - 18 SN - 0025-5793 DO - 10.1112/mtk.12175 UR - https://m2.mtmt.hu/api/publication/33561914 ID - 33561914 N1 - Export Date: 17 February 2023 Correspondence Address: Lángi, Z.; Department of Geometry, Műegyetem rkp. 3, Hungary; email: zlangi@math.bme.hu AB - The aim of this paper is to prove isoperimetric inequalities for simplices and polytopes with d+2$d+2$ vertices in Euclidean, spherical and hyperbolic d-space. In particular, we find the minimal volume d-dimensional hyperbolic simplices and spherical tetrahedra of a given inradius. Furthermore, we investigate the properties of maximal volume spherical and hyperbolic polytopes with d+2$d+2$ vertices with a given circumradius, and the hyperbolic polytopes with d+2$d+2$ vertices with a given inradius and having a minimal volume or minimal total edge length. Finally, for any 1 <= k <= d$1 \leqslant k \leqslant d$, we investigate the properties of Euclidean simplices and polytopes with d+2$d+2$ vertices having a fixed inradius and a minimal volume of its k-skeleton. The main tool of our investigation is Euclidean, spherical and hyperbolic Steiner symmetrization. LA - English DB - MTMT ER - TY - JOUR AU - Bezdek, Károly AU - Lángi, Zsolt TI - On k-diametral point configurations in Minkowski spaces JF - DISCRETE MATHEMATICS J2 - DISCRETE MATH VL - 345 PY - 2022 IS - 2 SN - 0012-365X DO - 10.1016/j.disc.2021.112700 UR - https://m2.mtmt.hu/api/publication/32517495 ID - 32517495 N1 - Department of Mathematics and Statistics, University of Calgary, Canada Department of Mathematics, University of Pannonia, Veszprém, Hungary MTA-BME Morphodynamics Research Group, Department of Geometry, Budapest University of Technology and Economics, Budapest, Hungary Export Date: 13 June 2023 CODEN: DSMHA Correspondence Address: Bezdek, K.; Department of Mathematics and Statistics, Canada; email: bezdek@math.ucalgary.ca AB - The structure of k-diametral point configurations in Minkowski d-space is shown to be closely related to the properties of k-antipodal point configurations in Rd. In particular, the maximum size of k-diametral point configurations of Minkowski d-spaces is obtained for given k >= 2 and d >= 2 generalizing Petty's results (Petty, 1971 [24]) on equilateral sets in Minkowski spaces. Furthermore, bounds are derived for the maximum size of k-diametral point configurations in given Minkowski d-space (resp., Euclidean d-space). Some of these results have analogues for point sets, which are discussed as well. In the proofs convexity methods are combined with volumetric estimates and combinatorial properties of diameter graphs. (C) 2021 Elsevier B.V. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Bozóki, Sándor AU - Domokos, Gábor AU - Kovács, Flórián AU - Regős, Krisztina TI - Mono-unstable polyhedra with point masses have at least 8 vertices JF - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES J2 - INT J SOLIDS STRUCT VL - 234-235 PY - 2022 PG - 10 SN - 0020-7683 DO - 10.1016/j.ijsolstr.2021.111276 UR - https://m2.mtmt.hu/api/publication/32461660 ID - 32461660 N1 - NKFIA ED_18-2-2018-0006; NKFIH Hungarian Research Fund 34199 LA - English DB - MTMT ER - TY - JOUR AU - Cao, Siwen AU - Sipos, András Árpád TI - Cracking patterns of brittle hemispherical domes: an experimental study JF - FRATTURA ED INTEGRITA STRUTTURALE J2 - FRATTURA INTEGR STRUTT VL - 16 PY - 2022 IS - 59 SP - 265 EP - 310 PG - 45 SN - 1971-8993 DO - 10.3221/IGF-ESIS.59.20 UR - https://m2.mtmt.hu/api/publication/32481039 ID - 32481039 AB - Crack formation in hemispherical domes is a distinguished problem in structural mechanics. The safety of cracked domes has a long track record; the evolution of the cracking pattern received less attention. Here, we report displacement-controlled loading tests of brittle hemispherical dome specimens, including the evolution of the meridional cracking pattern. The 27 investigated specimens, 20 cm in diameter, were prepared in 3D printed molds, and their material is one of the three mixtures of gypsum and cement. We find that neither the (limited) tensile strength nor the exact value of the thickness significantly affects the statistical description of the cracking pattern, i.e., the cracking phenomenon is robust. The maximal number of the meridional cracks never exceeds seven before the fragments’ disintegration (collapse). We find that the size distribution of the fragments exhibits a lognormal distribution. The evolution is reflected in the load-displacement diagrams recorded in the test, too, as significant drops in the force are accompanied by an emergence of one or more new cracks, reflecting the brittle nature of the phenomenon. A simple, stochastic fragmentation model, in which a segment is fragmented at either in the middle or at the fourth point, fairly recovers the observed size distribution. LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - Lángi, Zsolt TI - On Some Average Properties of Convex Mosaics JF - EXPERIMENTAL MATHEMATICS J2 - EXP MATH VL - 31 PY - 2022 IS - 3 SP - 783 EP - 793 PG - 11 SN - 1058-6458 DO - 10.1080/10586458.2019.1691090 UR - https://m2.mtmt.hu/api/publication/31009246 ID - 31009246 N1 - Cited By :6 Export Date: 18 March 2024 Correspondence Address: Lángi, Z.; MTA-BME Morphodynamics Research Group, Egry József utca 1, Hungary; email: zlangi@math.bme.hu Funding details: 119245 Funding details: Magyar Tudományos Akadémia, MTA Funding details: Emberi Eroforrások Minisztériuma, EMMI Funding text 1: Supported by the NKFIH Hungarian Research Fund grant 119245 and of grant BME FIKP-VÍZ by EMMI is kindly acknowledged. ZL has been supported by grant UNKP-19-4 New National Excellence Program of the Ministry of Innovation and Technology and the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. The authors are very grateful to Rolf Schneider for his repeated encouragement which contributed to shape this manuscript. We also thank Egon Schulte and Frank Morgan for their positive comments, and an anonymous referee for careful reading and valuable comments. AB - In a convex mosaic in we denote the average number of vertices of a cell by and the average number of cells meeting at a node by Except for the d = 2 planar case, there is no known formula prohibiting points in any range of the plane (except for the unphysical strips). Nevertheless, in d = 3 dimensions if we plot the 28 points corresponding to convex uniform honeycombs, the 28 points corresponding to their duals and the 3 points corresponding to Poisson-Voronoi, Poisson-Delaunay and random hyperplane mosaics, then these points appear to accumulate on a narrow strip of the plane. To explore this phenomenon we introduce the harmonic degree of a d-dimensional mosaic. We show that the observed narrow strip on the plane corresponds to a narrow range of We prove that for every there exists a convex mosaic with harmonic degree and we conjecture that there exist no d-dimensional mosaic outside this range. We also show that the harmonic degree has deeper geometric interpretations. In particular, in case of Euclidean mosaics it is related to the average of the sum of vertex angles and their polars, and in case of 2 D mosaics, it is related to the average excess angle. LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor TI - Natural Numbers, Natural Shapes JF - AXIOMATHES J2 - AXIOMATHES VL - 32 PY - 2022 IS - 5 SP - 743 EP - 763 PG - 21 SN - 1122-1151 DO - 10.1007/s10516-018-9411-5 UR - https://m2.mtmt.hu/api/publication/30808711 ID - 30808711 N1 - Cited By :2 Export Date: 8 October 2019 Article in Press Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group, Department of Mechanics, Materials and Structures, Budapest University of Technology, Műegyetem Rakpart 1-3., Hungary; email: domokos@iit.bme.hu Cited By :5 Export Date: 22 June 2021 Article in Press Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group, Műegyetem Rakpart 1-3., Hungary; email: domokos@iit.bme.hu Cited By :5 Export Date: 8 September 2021 Article in Press Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group, Műegyetem Rakpart 1-3., Hungary; email: domokos@iit.bme.hu Cited By :5 Export Date: 9 September 2021 Article in Press Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group, Műegyetem Rakpart 1-3., Hungary; email: domokos@iit.bme.hu AB - We explain the general significance of integer-based descriptors for natural shapes and show that the evolution of two such descriptors, called mechanical descriptors (the number N(t) of static balance points and the Morse–Smale graph associated with the scalar distance function measured from the center of mass) appear to capture (unlike classical geophysical shape descriptors) one of our most fundamental intuitions about natural abrasion: shapes get monotonically simplified in this process. Thus mechanical descriptors help to establish a correlation between subjective and objective descriptors of perceived objects. LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - Lángi, Zsolt TI - Plato’s Error and a Mean Field Formula for Convex Mosaics JF - AXIOMATHES J2 - AXIOMATHES VL - 32 PY - 2022 IS - 5 SP - 889 EP - 905 PG - 17 SN - 1122-1151 DO - 10.1007/s10516-019-09455-w UR - https://m2.mtmt.hu/api/publication/30799093 ID - 30799093 AB - Plato claimed that the regular solids are the building blocks of all matter. His views, commonly referred to as the geometric atomistic model, had enormous impact on human thought despite the fact that four of the five Platonic solids can not fill space without gaps. In this paper we quantify these gaps, showing that the errors in Plato’s estimates were quite small. We also develop a mean field approximation to convex honeycombs using a generalized version of Plato’s idea. This approximation not only admits to view convex mosaics in d=3 dimensions as a continuum but we also find that it is quite accurate, showing that Plato’s geometric intuition may have been remarkable. LA - English DB - MTMT ER - TY - JOUR AU - Domokos, Gábor AU - Lángi, Zsolt AU - Sipos, András Árpád TI - Tracking Critical Points on Evolving Curves and Surfaces JF - EXPERIMENTAL MATHEMATICS J2 - EXP MATH VL - 31 PY - 2022 IS - 1 SP - 1 EP - 20 PG - 20 SN - 1058-6458 DO - 10.1080/10586458.2018.1556136 UR - https://m2.mtmt.hu/api/publication/30548681 ID - 30548681 N1 - Export Date: 22 June 2021 Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group and Department of Mechanics, Műegyetem rakpart 1-3, Hungary; email: domokos@iit.bme.hu Export Date: 8 September 2021 Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group and Department of Mechanics, Műegyetem rakpart 1-3, Hungary; email: domokos@iit.bme.hu Export Date: 9 September 2021 Correspondence Address: Domokos, G.; MTA-BME Morphodynamics Research Group and Department of Mechanics, Műegyetem rakpart 1-3, Hungary; email: domokos@iit.bme.hu AB - In recent years it became apparent that geophysical abrasion can be well characterized by the time evolution N(t) of the number N of static balance points of the abrading particle. Static balance points correspond to the critical points of the particle's surface represented as a scalar distance function r, measured from the center of mass of the particle, so their time evolution can be expressed as N (r (t)) . The mathematical model of the particle can be constructed on two scales: on the macro (global) scale the particle may be viewed as a smooth, convex manifold described by the smooth distance function r with N = N (r) equilibria, while on the micro (local) scale the particle's natural model is a finely discretized, convex polyhedral approximation r(Delta) of r, with N-Delta = N(r(Delta)) equilibria. There is strong intuitive evidence suggesting that under some particular evolution models (e.g., curvature-driven flows) N(t) and N (Delta)(t) primarily evolve in the opposite manner (i.e. if one is increasing then the other is decreasing and vice versa). This observation appears to be a key factor in tracking geophysical abrasion. Here we create the mathematical framework necessary to understand these phenomena more broadly, regardless of the particular evolution equation. We study micro and macro events in one-parameter families of curves and surfaces, corresponding to bifurcations triggering the jumps in N(t) and N (Delta)(t). Based on this analysis we show that the intuitive picture developed for curvature-driven flows is not only correct, it has universal validity, as long as the evolving surface r is smooth. In this case, bifurcations associated with r and r (Delta) are coupled to some extent: resonance-like phenomena in N (Delta)(t) can be used to forecast downward jumps in N(t) (but not upward jumps). Beyond proving rigorous results in the case of evolving planar curves for the Delta -> 0 limit on the nontrivial interplay between singularities in the discrete and continuum approximations we also show that our mathematical model is structurally stable. This property serves as the basis for the second, experimental part of our research where we demonstrate via computer simulations that the phenomena on evolving surfaces appear to be closely analogous to the planar case, however, they also show additional geometric features which are still not completely understood. LA - English DB - MTMT ER - TY - BOOK ED - Dubniczky, Miklós ED - Hegyi, Dezső TI - DUILI 90 PB - Magyar Mérnöki Kamara Tartószerkezeti Tagozat CY - Budapest PY - 2022 SP - 479 SN - 9786158196536 UR - https://m2.mtmt.hu/api/publication/33704751 ID - 33704751 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Fehér, Eszter AU - Havasi-Tóth, Balázs AU - Ludmány, Balázs TI - Fully spherical 3D datasets on sedimentary particles: Fast measurement and evaluation JF - CENTRAL EUROPEAN GEOLOGY J2 - CENT EUR GEOL VL - 65 PY - 2022 IS - 2 SP - 111 EP - 121 PG - 11 SN - 1788-2281 DO - 10.1556/24.2022.00124 UR - https://m2.mtmt.hu/api/publication/33093510 ID - 33093510 N1 - MTA-BME Morphodynamics Research Group, Budapest, Hungary Department of Morphology and Geometric Modeling, Budapest University of Technology and Economics, Budapest, Hungary Department of Fluid Mechanics, Budapest University of Technology and Economics, Budapest, Hungary Department of Control Engineering and Information Technology, Budapest University of Technology and Economics, Budapest, Hungary Cited By :1 Export Date: 11 December 2023 Correspondence Address: Fehér, E.; Department of Morphology and Geometric Modeling, K220, Műegyetem rkp. 1–3, Hungary; email: feher.eszter@epk.bme.hu Funding details: 134199 Funding details: Emberi Eroforrások Minisztériuma, EMMI Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding details: Innovációs és Technológiai Minisztérium, BME-NVA-02 Funding text 1: The authors would like to thank Krisztián Halmos for carrying out the hand measurements and for helping with the 3D scanning; Gábor Domokos for the fruitful discussions and his help in the field study; Bernd Krauskopf for helping to find a location to test the method; Géza Tóth for helping to build the camera crane. This research, supported by the NKFIH Hungarian Research Fund Grant 134199 and by Grant BME FIKP-VÍZ by EMMI, is gratefully acknowledged. The research reported in this paper and carried out at BME has been supported by the NRDI Fund (TKP2020 NC, Grant No. BMENCS) based on the charter of bolster issued by the NRDI Office under the auspices of the Ministry for Innovation and Technology. This research is also part of project no. BME-NVA-02, implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021 funding scheme. AB - Recently it became increasingly evident that the statistical distributions of size and shape descriptors of sedimentary particles reveal crucial information on their evolution and may even carry the fingerprints of their provenance as fragments. However, to unlock this trove of information, measurement of traditional geophysical shape descriptors (mostly detectable on 2D projections) is not sufficient; fully spherical 3D imaging and mathematical algorithms suitable to extract new types of inherently 3D shape descriptors are necessary. Available 3D imaging technologies force users to choose either speed or full sphericity. Only partial morphological information can be extracted in the absence of the latter (e.g., LIDAR imaging). In the case of fully spherical imaging, speed was proved to be prohibitive for obtaining meaningful statistical samples, and inherently 3D shape descriptors were not extracted. Here we present a new method by complementing a commercial, portable 3D scanner with simple hardware to quickly obtain fully spherical 3D datasets from large collections of sedimentary particles. We also present software for the automated extraction of 3D shapes and automated measurement of inherently 3D-shape properties. This technique allows for examining large samples without the need for transportation or storage of the samples, and it may also facilitate the collaboration of geographically distant research groups. We validated our software on a large sample of pebbles by comparing previously hand-measured parameters with the results of automated shape analysis. We also tested our hardware and software tools on a large pebble sample in Kawakawa Bay, New Zealand. LA - English DB - MTMT ER - TY - JOUR AU - Fradelizi, Matthieu AU - Lángi, Zsolt AU - Zvavitch, Artem TI - Volume of the Minkowski sums of star-shaped sets JF - PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY SERIES B J2 - PROC AMER MATH SOC.SER B VL - 9 PY - 2022 IS - 34 SP - 358 EP - 372 PG - 15 SN - 2330-1511 DO - 10.1090/bproc/97 UR - https://m2.mtmt.hu/api/publication/33078387 ID - 33078387 N1 - Export Date: 8 November 2022 AB - For a compact set A ⊂ R d A \subset \mathbb {R}^d and an integer k ≥ 1 k\ge 1 , let us denote by A [ k ] = { a 1 + ⋯ + a k : a 1 , … , a k ∈ A } = ∑ i = 1 k A \begin{equation*} A[k] = \left \{a_1+\cdots +a_k: a_1, \ldots , a_k\in A\right \}=\sum _{i=1}^k A \end{equation*} the Minkowski sum of k k copies of A A . A theorem of Shapley, Folkmann and Starr (1969) states that 1 k A [ k ] \frac {1}{k}A[k] converges to the convex hull of A A in Hausdorff distance as k k tends to infinity. Bobkov, Madiman and Wang [ Concentration, functional inequalities and isoperimetry , Amer. Math. Soc., Providence, RI, 2011] conjectured that the volume of 1 k A [ k ] \frac {1}{k}A[k] is nondecreasing in k k , or in other words, in terms of the volume deficit between the convex hull of A A and 1 k A [ k ] \frac {1}{k}A[k] , this convergence is monotone. It was proved by Fradelizi, Madiman, Marsiglietti and Zvavitch [C. R. Math. Acad. Sci. Paris 354 (2016), pp. 185–189] that this conjecture holds true if d = 1 d=1 but fails for any d ≥ 12 d \geq 12 . In this paper we show that the conjecture is true for any star-shaped set A ⊂ R d A \subset \mathbb {R}^d for d = 2 d=2 and d = 3 d=3 and also for arbitrary dimensions d ≥ 4 d \ge 4 under the condition k ≥ ( d − 1 ) ( d − 2 ) k \ge (d-1)(d-2) . In addition, we investigate the conjecture for connected sets and present a counterexample to a generalization of the conjecture to the Minkowski sum of possibly distinct sets in R d \mathbb {R}^d , for any d ≥ 7 d \geq 7 . LA - English DB - MTMT ER - TY - JOUR AU - Gáspár, Orsolya TI - The optimization process leading to the tessellation of the first geodesic dome structure, the first Planetarium of Jena JF - INTERNATIONAL JOURNAL OF SPACE STRUCTURES J2 - INT J SPACE STRUCT VL - 37 PY - 2022 IS - 1 SP - 49 EP - 64 PG - 16 SN - 0956-0599 DO - 10.1177/09560599211064110 UR - https://m2.mtmt.hu/api/publication/32528369 ID - 32528369 LA - English DB - MTMT ER - TY - JOUR AU - G. Horváth, Ákos AU - Lángi, Zsolt TI - On the convex hull and homothetic convex hull functions of a convex body JF - GEOMETRIAE DEDICATA J2 - GEOMETRIAE DEDICATA VL - 216 PY - 2022 IS - 1 PG - 12 SN - 0046-5755 DO - 10.1007/s10711-022-00673-y UR - https://m2.mtmt.hu/api/publication/32613562 ID - 32613562 N1 - Funding Agency and Grant Number: BME Water Sciences & Disaster Prevention TKP2020 IE of the National Research, Development and Innovation Fund (NRDI); New National Excellence Program of the Ministry for Innovation and Technology [UNKP-20-5]; Janos Bolyai Scholarship of the Hungarian Academy of SciencesHungarian Academy of Sciences; [K119670] Funding text: Z. Langi was supported by grants K119670 and BME Water Sciences & Disaster Prevention TKP2020 IE of the National Research, Development and Innovation Fund (NRDI), by the UNKP-20-5 New National Excellence Program of the Ministry for Innovation and Technology, and the Janos Bolyai Scholarship of the Hungarian Academy of Sciences. AB - The aim of this note is to investigate the properties of the convex hull and the homothetic convex hull functions of a convex body K in Euclidean n-space, defined as the volume of the union of K and one of its translates, and the volume of K and a translate of a homothetic copy of K, respectively, as functions of the translation vector. In particular, we prove that the convex hull function of the body K does not determine K. Furthermore, we prove the equivalence of the polar projection body problem raised by Petty, and a conjecture of G.Horváth and Lángi about translative constant volume property of convex bodies. We give a short proof of some theorems of Jerónimo-Castro about the homothetic convex hull function, and prove a homothetic variant of the translative constant volume property conjecture for 3-dimensional convex polyhedra. We also apply our results to describe the properties of the illumination bodies of convex bodies. LA - English DB - MTMT ER - TY - BOOK AU - Haba, Péter AU - Gáspár, Orsolya TI - Finding Nervi – On-site precasting in the Hungarian industrial architecture. Lecture at: "Cold War Interactions: Architectural Exchange Between Italy and the Socialist East" conference and workshop, curated by Alessandro De Magistris, Federico Deambrosis, Ákos Moravánszky, Luca Skansi – Politecnico di Milano, PY - 2022 UR - https://m2.mtmt.hu/api/publication/34491158 ID - 34491158 LA - English DB - MTMT ER - TY - CONF AU - Havasi-Tóth, Balázs TI - Improving the incompressibility condition of the explicit SPH method using the control theory T2 - CMFF’22 Workshop on " Coupling techniques in multiscale atmospheric models: Microphysics, local scale simulations, PBL structureels" PY - 2022 SP - 522 EP - 528 PG - 6 UR - https://m2.mtmt.hu/api/publication/33096462 ID - 33096462 LA - English DB - MTMT ER - TY - JOUR AU - Hegyi, Dezső AU - Armuth, Miklós AU - Halmos, Balázs AU - Marótzy, Katalin TI - The effect of wind on historical timber towers analyzed by plastic limit analysis in the focus of a collapse JF - ENGINEERING FAILURE ANALYSIS J2 - ENG FAIL ANAL VL - 134 PY - 2022 PG - 19 SN - 1350-6307 DO - 10.1016/j.engfailanal.2021.105852 UR - https://m2.mtmt.hu/api/publication/32604626 ID - 32604626 N1 - Funding Agency and Grant Number: National Research, Development and Innovation Office in the field of Water Sciences & Disaster Prevention [BME IE-VIZ TKP2020, TKP 2021-BME-NVA] Funding text: The research reported in this paper and carried out at the Budapest University of Technology and Economics was supported by the "TKP2020 and TKP2021, Institutional Excellence Program" of the National Research, Development and Innovation Office in the field of Water Sciences & Disaster Prevention (BME IE-VIZ TKP2020 and TKP 2021-BME-NVA) . AB - Climate change severely impacts the architectural heritage. Old buildings may have survived many large storms and heavy snows in the past, but extremes have increased recently. Meanwhile, the condition of historical structures gradually degrades even if they have had regular maintenance. Church towers are strongly affected: they are subject to increased wind compared to the other parts of the building. They are in a high location and gain less attention because of their out-of-the-way position. On 17th September 2017, a massive storm in the Banat region, Romania, caused several church towers to collapse: the towers of Toager, Remetea Mare, Donceni and Ghilad fell down to pieces that day. The collapse of the tower of Dumbrava was one of the buildings involved, this study aims to clarify whether the poor condition of the building, or the flaw of the original design was the main reason for the failure in this village. The structural analysis of such historical timber structures can be problematic as the weak joints of the structure limit the load-bearing capacitance in an exceptionally low level if the traditional elastic analysis is used. The present paper points out that the plastic limit analysis can give a more realistic breaking load level for the high order statically indeterminate carpenter roofs. LA - English DB - MTMT ER - TY - BOOK AU - Hegyi, Dezső AU - Gáspár, Orsolya AU - Fehér, Eszter TI - Különleges tartószerkezetek PB - TERC Kereskedelmi és Szolgáltató Kft CY - Budapest PY - 2022 SP - 290 SN - 9786155445903 UR - https://m2.mtmt.hu/api/publication/33072765 ID - 33072765 LA - English DB - MTMT ER - TY - JOUR AU - Ködmön, Csenge Lili AU - Lángi, Zsolt TI - Extremal convex polygons inscribed in a given convex polygon JF - COMPUTATIONAL GEOMETRY-THEORY AND APPLICATIONS J2 - COMP GEOM-THEOR APPL VL - 102 PY - 2022 PG - 10 SN - 0925-7721 DO - 10.1016/j.comgeo.2021.101844 UR - https://m2.mtmt.hu/api/publication/32541127 ID - 32541127 N1 - Funding Agency and Grant Number: National Research, Development and Innovation Office, NKFI [K-119670]; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences; New National Excellence Program by the Ministry for Innovation and Technology [BME IE-VIZ TKP2020, UNKP20-5] Funding text: The second author was supported by the National Research, Development and Innovation Office, NKFI, K-119670, the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences, and the grants BME IE-VIZ TKP2020 and UNKP20-5 New National Excellence Program by the Ministry for Innovation and Technology. AB - A convex polygon Q is inscribed in a convex polygon P if every side of P contains at least one vertex of Q. We present algorithms for finding a minimum area and a minimum perimeter convex polygon inscribed in any given convex n-gon in O(n) and O(n(3)) time, respectively. We also investigate other variants of this problem. LA - English DB - MTMT ER - TY - JOUR AU - Köhserli, Mehmet AU - Várkonyi, Péter László TI - The Effect of Connecting Bridges on Vortex-induced Vibration of Skyscrapers JF - ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY J2 - ÉPÍTÉS-ÉPÍTÉSZETTUDOMÁNY VL - 50 PY - 2022 IS - 1-2 SP - 1 EP - 16 PG - 16 SN - 0013-9661 DO - 10.1556/096.2021.00019 UR - https://m2.mtmt.hu/api/publication/32658376 ID - 32658376 N1 - Export Date: 5 May 2022 Correspondence Address: Várkonyi, P.L.; Department of Mechanics, K II. 61, Muegyetem rkp. 3, Hungary; email: varkonyi.peter@epk.bme.hu LA - English DB - MTMT ER - TY - JOUR AU - Lángi, Zsolt TI - A solution to some problems of Conway and Guy on monostable polyhedra JF - BULLETIN OF THE LONDON MATHEMATICAL SOCIETY J2 - B LOND MATH SOC VL - 54 PY - 2022 IS - 2 SP - 501 EP - 516 PG - 16 SN - 0024-6093 DO - 10.1112/blms.12579 UR - https://m2.mtmt.hu/api/publication/32749811 ID - 32749811 N1 - Funding Agency and Grant Number: National Research, Development and Innovation OfficeNational Research, Development & Innovation Office (NRDIO) - Hungary [K-119245]; Hungarian Academy of SciencesHungarian Academy of Sciences; Ministry of Innovation and Technology; NRDI FundNational Research, Development & Innovation Office (NRDIO) - Hungary [TKP2020 BME-IKA-VIZ] Funding text: National Research, Development and Innovation Office, Grant/Award Number: K-119245; Hungarian Academy of Sciences; Ministry of Innovation and Technology; NRDI Fund, Grant/Award Number: TKP2020 BME-IKA-VIZ AB - A convex polyhedron is called monostable if it can rest in stable position only on one of its faces. The aim of this paper is to investigate three questions of Conway, regarding monostable polyhedra, which first appeared in a 1969 paper of Goldberg and Guy. In this note, we answer two of these problems and make a conjecture about the third one. The main tool of our proof is a general theorem describing approximations of smooth convex bodies by convex polyhedra in terms of their static equilibrium points. As another application of this theorem, we prove the existence of a convex polyhedron with only one stable and one unstable point. LA - English DB - MTMT ER - TY - JOUR AU - Lángi, Zsolt TI - An isoperimetric problem for three-dimensional parallelohedra JF - PACIFIC JOURNAL OF MATHEMATICS J2 - PAC J MATH VL - 316 PY - 2022 IS - 1 SP - 169 EP - 181 PG - 13 SN - 0030-8730 DO - 10.2140/pjm.2022.316.169 UR - https://m2.mtmt.hu/api/publication/32729942 ID - 32729942 N1 - Export Date: 4 May 2022 Correspondence Address: Lángi, Z.; Morphodynamics Research Group And Department Of Geometry, Hungary; email: zlangi@math.bme.hu AB - The aim of this note is to investigate isoperimetric-type problems for 3-dimensional parallelohedra; that is, for convex polyhedra whose translates tile the 3-dimensional Euclidean space. Our main result states that among 3-dimensional parallelohedra with unit volume, the one with minimal mean width is the regular truncated octahedron. LA - English DB - MTMT ER - TY - JOUR AU - Ludmány, Balázs AU - Domokos, Gábor TI - Pebbles, graphs and equilibria: Higher order shape descriptors for sedimentary particles JF - CENTRAL EUROPEAN GEOLOGY J2 - CENT EUR GEOL VL - 65 PY - 2022 IS - 2 SP - 158 EP - 177 PG - 20 SN - 1788-2281 DO - 10.1556/24.2023.00135 UR - https://m2.mtmt.hu/api/publication/34174919 ID - 34174919 N1 - HUN-REN-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Budapest, Hungary Department of Control Engineering and Information Technology, Budapest University of Technology and Economics, Budapest, Hungary Department of Morphology and Geometric Modeling, Budapest University of Technology and Economics, Budapest, Hungary Export Date: 16 November 2023 Correspondence Address: Ludmány, B.; HUN-REN-BME Morphodynamics Research Group, Hungary; email: ludmany.balazs@cloud.bme.hu AB - While three-dimensional measurement technology is spreading fast, its meaningful application to sedimentary geology still lacks content. Classical shape descriptors (such as axis ratios, circularity of projection) were not inherently three-dimensional, because no such technology existed. Recently a new class of three-dimensional descriptors, collectively referred to as mechanical descriptors, has been introduced and applied for a broad range of sedimentary particles. First-order mechanical descriptors (registered for each pebble as a pair {S, U} of integers), refer to the respective numbers of stable and unstable static equilibria and can be reliably detected by hand experiments. However, they have limited ability of distinction, as the majority of coastal pebbles fall into primary class . Higher-order mechanical descriptors offer a more refined distinction. However, for the extraction of these descriptors (registered as graphs for each pebble), hand measurements are not an option and even computer-based extraction from 3D scans offers a formidable challenge. Here we not only describe and implement an algorithm to perform this task, but also apply it to a collection of 271 pebbles with various lithologies, illustrating that the application of higher-order descriptors is a viable option for geologists. We also show that the so-far uncharted connection between the two known secondary descriptors, the so-called Morse–Smale graph and the Reeb-graph, can be established via a third order descriptor which we call the master graph. LA - English DB - MTMT ER - TY - CHAP AU - Michel, Sébastien AU - Sipos, András Árpád ED - Marco, di Prisco ED - Alberto, Meda ED - Balázs, György László TI - A numerical study of the cracking pattern of reinforced concrete rings under hydrostatic pressure T2 - Proceedings of the 14th fib International PhD Symposium in Civil Engineering PB - International Federation for Structural Concrete (fib) CY - Lausanne SN - 9782940643172 T3 - Fib symposium proceedings, ISSN 2617-4820 ; 58. PY - 2022 SP - 361 EP - 367 PG - 8 UR - https://m2.mtmt.hu/api/publication/33089405 ID - 33089405 N1 - Export Date: 15 December 2022 LA - English DB - MTMT ER - TY - JOUR AU - Michel, Sébastien AU - Sipos, András Árpád TI - On the cracking patterns of brittle rings with elastic radial support under hydrostatic pressure JF - MECCANICA J2 - MECCANICA VL - 57 PY - 2022 IS - 1 SP - 1639 EP - 1656 PG - 18 SN - 0025-6455 DO - 10.1007/s11012-022-01523-7 UR - https://m2.mtmt.hu/api/publication/32795154 ID - 32795154 N1 - Funding Agency and Grant Number: Budapest University of Technology and Economics Funding text: Open access funding provided by Budapest University of Technology and Economics. LA - English DB - MTMT ER - TY - JOUR AU - Pongó, Tivadar AU - Fan, Bo AU - Hernández-Delfin, D. AU - Török, János AU - Stannarius, R. AU - Hidalgo, R.C. AU - Börzsönyi, Tamás TI - The role of the particle aspect ratio in the discharge of a narrow silo JF - NEW JOURNAL OF PHYSICS J2 - NEW J PHYS VL - 24 PY - 2022 IS - 10 PG - 13 SN - 1367-2630 DO - 10.1088/1367-2630/ac9923 UR - https://m2.mtmt.hu/api/publication/33608718 ID - 33608718 LA - English DB - MTMT ER - TY - JOUR AU - Preißinger, Katharina AU - Kellermayer, Miklós AU - Vértessy, Beáta (Grolmuszné) AU - Kézsmárki, István AU - Török, János TI - Reducing data dimension boosts neural network-based stage-specific malaria detection JF - SCIENTIFIC REPORTS J2 - SCI REP VL - 12 PY - 2022 IS - 1 PG - 14 SN - 2045-2322 DO - 10.1038/s41598-022-19601-x UR - https://m2.mtmt.hu/api/publication/33133343 ID - 33133343 AB - Although malaria has been known for more than 4 thousand years 1 , it still imposes a global burden with approx. 240 million annual cases 2 . Improvement in diagnostic techniques is a prerequisite for its global elimination. Despite its main limitations, being time-consuming and subjective, light microscopy on Giemsa-stained blood smears is still the gold-standard diagnostic method used worldwide. Autonomous computer assisted recognition of malaria infected red blood cells (RBCs) using neural networks (NNs) has the potential to overcome these deficiencies, if a fast, high-accuracy detection can be achieved using low computational power and limited sets of microscopy images for training the NN. Here, we report on a novel NN-based scheme that is capable of the high-speed classification of RBCs into four categories—healthy ones and three classes of infected ones according to the parasite age—with an accuracy as high as 98%. Importantly, we observe that a smart reduction of data dimension, using characteristic one-dimensional cross-sections of the RBC images, not only speeds up the classification but also significantly improves its performance with respect to the usual two-dimensional NN schemes. Via comparative studies on RBC images recorded by two additional techniques, fluorescence and atomic force microscopy, we demonstrate that our method is universally applicable for different types of microscopy images. This robustness against imaging platform-specific features is crucial for diagnostic applications. Our approach for the reduction of data dimension could be straightforwardly generalised for the classification of different parasites, cells and other types of objects. LA - English DB - MTMT ER - TY - JOUR AU - Sipos, András Árpád AU - Várkonyi, Péter László TI - A unified morphoelastic rod model with application to growth-induced coiling, waving, and skewing of plant roots JF - JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS J2 - J MECH PHYS SOLIDS VL - 160 PY - 2022 PG - 14 SN - 0022-5096 DO - 10.1016/j.jmps.2022.104789 UR - https://m2.mtmt.hu/api/publication/32623795 ID - 32623795 AB - The shapes of roots exhibit distinctive patterns, which attracted significant attempts at an explanation. We develop a geometrically exact, elastic, three-dimensional morphoelastic rod model of root elongation coupled with control mechanisms representing circumnutation, gravitropism, and thigmotropism. Possible forms of the evolution equations for the intrinsic curvature of the rod, representing these control mechanisms are discussed. By specifying the evolution rules of intrinsic curvatures, the model boils down to a sequential solution of two-point boundary value problems in order to compute the evolving root shape. We simulate root growth on hard soil surfaces with different angles of inclination. Systematic computations show that the morphology is predominantly determined by the model parameters associated with the control mechanisms and by the angle of inclination. Predictions of the new model recover experimentally observed root coiling, waving, and skewing of Arabidopsis thaliana. Our results suggest that the primary mechanism behind root coiling, waving, and skewing is the interplay between circumnutation and gravitropism as slope angle is varied. Thigmotropism has a moderate effect on the emerging shapes. LA - English DB - MTMT ER - TY - CHAP AU - Cao, Siwen AU - Sipos, András Árpád ED - Marco, di Prisco ED - Alberto, Meda ED - Balázs, György László TI - Experimental study of crack propagation in a brittle hemispherical dome with two pre-existing cracks T2 - Proceedings of the 14th fib International PhD Symposium in Civil Engineering PB - International Federation for Structural Concrete (fib) CY - Lausanne SN - 9782940643172 T3 - Fib symposium proceedings, ISSN 2617-4820 ; 58. PY - 2022 SP - 589 EP - 596 PG - 8 UR - https://m2.mtmt.hu/api/publication/33089425 ID - 33089425 N1 - Export Date: 15 December 2022 LA - English DB - MTMT ER - TY - CHAP AU - Ther, Péter Pál AU - Sajtos, István ED - Marco, di Prisco ED - Alberto, Meda ED - Balázs, György László TI - Effect of load path bifurcation on the behavior of reinforced concrete beams T2 - Proceedings of the 14th fib International PhD Symposium in Civil Engineering PB - International Federation for Structural Concrete (fib) CY - Lausanne SN - 9782940643172 T3 - Fib symposium proceedings, ISSN 2617-4820 ; 58. PY - 2022 SP - 97 EP - 104 PG - 8 UR - https://m2.mtmt.hu/api/publication/33282346 ID - 33282346 AB - Practical experience shows that the final failure mode of RC beams is asymmetric even in a symmetric experimental setup. This is due to the strain-softening behavior of concrete, which leads to the bifurca-tion of the symmetrical load path. The paper aims to analyze the effect of the failure mode of RC beams without shear reinforcement on the load-bearing capacity and deformational ability (i.e. displacement and rotation). We used ATENA, a nonlinear finite element software to examine the effect of beam size, reinforcement ratio, and fracture energy on the failure mode, load-bearing capacity, and deformational ability of RC beams. The paper also compares experimental and numerical results and explains how the numerical model-ling technique may lead to incorrect results. LA - English DB - MTMT ER - TY - CHAP AU - Várkonyi, Péter László AU - Guerra Riaño, Andres Felipe ED - Szakál, Anikó TI - From swinging cables to adaptive funicular structures in architecture T2 - IEEE 20th Jubilee International Symposium on Intelligent Systems and Informatics (SISY 2022) PB - IEEE CY - Szabadka SN - 9781665489881 PY - 2022 SP - 169 EP - 174 PG - 6 DO - 10.1109/SISY56759.2022.10036184 UR - https://m2.mtmt.hu/api/publication/33834348 ID - 33834348 N1 - IEEE CI Chapter; IEEE CS Chapter; IEEE Hungary Section; IEEE IES and RAS Joint Chapter; IEEE SMC Chapter Conference code: 186732 Export Date: 11 December 2023 Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH, 143175 Funding text 1: This work has been supported by the National Research, Development and Innovation office of Hungary under grant 143175. LA - English DB - MTMT ER - TY - JOUR AU - Várkonyi, Péter László AU - Kocsis, Marton AU - Ther, Tamás TI - Rigid impacts of three-dimensional rocking structures JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 107 PY - 2022 IS - 3 SP - 1839 EP - 1858 PG - 20 SN - 0924-090X DO - 10.1007/s11071-021-06934-x UR - https://m2.mtmt.hu/api/publication/32606864 ID - 32606864 N1 - Funding Agency and Grant Number: Budapest University of Technology and Economics Funding text: Open access funding provided by Budapest University of Technology and Economics. AB - Studies of rocking motion aim to explain the remarkable earthquake resistance of rocking structures. State-of-the-art assessment methods are mostly based on planar models, despite ongoing efforts to understand the significance of three-dimensionality. Impacts are essential components of rocking motion. We present experimental measurements of free-rocking blocks on a rigid surface, focusing on extreme sensitivity of impacts to geometric imperfections, unpredictability, and the emergence of three-dimensional motion via spontaneous symmetry breaking. These results inspire the development of new impact models of three-dimensional facet and edge impacts of polyhedral objects. Our model is a natural generalization of existing planar models based on the seminal work of George W. Housner. Model parameters are estimated empirically for rectangular blocks. Finally, new perspectives in earthquake assessment of rocking structures are discussed. LA - English DB - MTMT ER - TY - JOUR AU - Baranyai, Tamás TI - Corrigendum to “On the admissible dualities in Maxwell’s reciprocal construction” [Int. J. Solids Struct. 171 (2019) pages 10–16] JF - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES J2 - INT J SOLIDS STRUCT VL - 225 PY - 2021 SN - 0020-7683 DO - 10.1016/j.ijsolstr.2021.111058 UR - https://m2.mtmt.hu/api/publication/32872704 ID - 32872704 N1 - Export Date: 15 June 2022 LA - English DB - MTMT ER - TY - CONF AU - Baranyai, Tamás TI - The force as a function: Towards analytical graphic statics for spatial structures T2 - IASS 2020/21 Surrey Symposium PB - International Association for Shell and Spatial Structures (IASS) T3 - Proceedings of the IASS annual symposium, ISSN 2518-6582 ; 2020. PY - 2021 SP - 1637 EP - 1646 PG - 10 UR - https://m2.mtmt.hu/api/publication/32735565 ID - 32735565 LA - English DB - MTMT ER - TY - JOUR AU - Baranyai, Tamás TI - Analytical graphic statics JF - INTERNATIONAL JOURNAL OF SPACE STRUCTURES J2 - INT J SPACE STRUCT VL - 36 PY - 2021 IS - 2 SP - 117 EP - 126 PG - 10 SN - 0956-0599 DO - 10.1177/09560599211001651 UR - https://m2.mtmt.hu/api/publication/32033263 ID - 32033263 LA - English DB - MTMT ER - TY - JOUR AU - Barros, Joaquim AU - Sanz, Beatriz AU - Kabele, Petr AU - Yu, Rena C. AU - Meschke, Günther AU - Planas, Jaime AU - Cunha, Vitor AU - Caggiano, Antonio AU - Ozyurt, Nilüfer AU - Gouveia, Ventura AU - Bos, Ab AU - Poveda, Elisa AU - Gal, Erez AU - Cervenka, Jan AU - Neu, Gerrit E. AU - Rossi, Pierre AU - Dias‐da‐Costa, Daniel AU - Juhász, Károly Péter AU - Cendon, David AU - Ruiz, Gonzalo AU - Valente, Tiago TI - Blind competition on the numerical simulation of steel‐fiber‐reinforced concrete beams failing in shear JF - STRUCTURAL CONCRETE J2 - STRUCT CONCRETE VL - 22 PY - 2021 IS - 2 SP - 939 EP - 967 PG - 29 SN - 1464-4177 DO - 10.1002/suco.202000345 UR - https://m2.mtmt.hu/api/publication/32133519 ID - 32133519 N1 - Full Department of Civil Engineering, School of Engineering, University of Minho, Guimarães, Portugal Department of Materials Science, Technical University of Madrid, ETS de Ingenieros de Caminos, Madrid, Spain Department of Mechanics, Czech Technical University in Prague, Prague, Czech Republic Departamento de Mecánica Aplicada e Ingeniería de Proyectos, University of Castilla-La Mancha, Ciudad Real, Spain Department for Civil and Environmental Engineering Sciences, Ruhr University Bochum, Bochum, Germany Department of Materials Science, Technical University of Madrid, Madrid, Spain ISISE, Institute of Science and Innovation for Bio-Sustainability (IB-S), Department of Civil Engineering, University of Minho, Braga, Portugal Institut für Werkstoffe im Bauwesen, Technische Universität Darmstadt, Darmstadt, Germany Department of Civil Engineering, Bogazici University, Istanbul, Turkey Department of Civil Engineering, Polytechnic Institute of Viseu, Viseu, Portugal DIANAFEA, Delft, Netherlands Department of Structural Engineering, Ben-Gurion University of Negev, Be'er Sheva, Israel Červenka Consulting s.r.o, Prague, Czech Republic Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux, University of Eiffel, Paris, France School of Civil Engineering, The University of Sydney, Sydney, Australia Department of Mechanics, Materials and Structures, Budapest University of Technology and Economics, Budapest, Hungary Structural Design and Software Development, CiviTest-Pesquisa de Novos Materiais para a Engenharia Civil, Vila Nova de Famalicao, Portugal Cited By :4 Export Date: 5 July 2022 Correspondence Address: Barros, J.; Full Department of Civil Engineering, Portugal; email: barros@civil.uminho.pt Funding details: Fundação para a Ciência e a Tecnologia, FCT, PGC2018-097116-A-I00, PTDC/ECI-CON/27990/2017 Funding text 1: The authors acknowledge the support provided by FCT through the project ICoSyTec, reference PTDC/ECI-CON/27990/2017, and PGC2018-097116-A-I00 (MCIU/AEI/FEDER, UE). In addition, they express their gratitude for the support provided by the companies Casais, for production of the beams, and CiviTest, for the execution of the specimens and the experimental tests for the characterization of the mechanical properties of the SFRC and steel bars of the conventional reinforcements of the BSC. Last but not least, they are grateful for the support from fib on the dissemination of the BSC. AB - Experimental research has shown the extraordinary potential of the addition of short fibers to cement-based materials by improving significantly the behavior of concrete structures for serviceability and ultimate limit states. Software based on the finite element method has been used for the simulation of the material nonlinear behavior of fiber-reinforced concrete (FRC) structures. The applicability of the existing approaches has often been assessed by simulating experimental tests with structural elements, in general of a small scale, where the parameter values of the material constitutive laws are adjusted for the aimed predicting level, which constitutes an inverse technique of arguable utility for structural design practice. For assessing the predictive performance of these approaches, a blind simulation competition was organized. Two twin T-cross section steel FRC beams, flexurally reinforced with steel bars and without conventional shear reinforcement in the critical shear span, were experimentally tested up to failure. Despite the experimental data provided for the definition of the relevant model parameters, inaccuracies on the load capacity, deflection, and strain at peak load attained 40, 113, and 600%, respectively. Inadequate failure modes and highly different results were estimated with the same commercial software, indicating the need for deeper analysis and understanding of the models and influence of their parameters on their predictive performance. LA - English DB - MTMT ER - TY - JOUR AU - Erdélyiné Tóth, Mária AU - Pluzsik, Anikó TI - Using SDA Model in the Designing Process of Fiber-Reinforced Concrete Beams JF - JOURNAL OF MATERIALS IN CIVIL ENGINEERING J2 - J MATER CIVIL ENG VL - 33 PY - 2021 IS - 8 SP - 04021191 SN - 0899-1561 DO - 10.1061/(ASCE)MT.1943-5533.0003803 UR - https://m2.mtmt.hu/api/publication/32036139 ID - 32036139 N1 - Export Date: 4 October 2022 Correspondence Address: Erdélyiné Tóth, M.; Faculty of Architecture, Hungary; email: tothmarcsi94@gmail.com LA - English DB - MTMT ER - TY - JOUR AU - Fehér, Eszter AU - Domokos, Gábor AU - Krauskopf, Bernd TI - Tracking the critical points of curves evolving under planar curvature flows JF - JOURNAL OF COMPUTATIONAL DYNAMICS J2 - J COMPUT DYNAM VL - 8 PY - 2021 IS - 4 SP - 447 EP - 494 PG - 48 SN - 2158-2491 DO - 10.3934/jcd.2021017 UR - https://m2.mtmt.hu/api/publication/32476286 ID - 32476286 N1 - MTA-BME Morphodynamics Research Group Department of Morphology and Geometric, Modeling Budapest University of Technology and Economics Muegyetem, rakpart 1-3., Budapest, 1111, Hungary Department of Mechanics, Materials and Structures, Budapest University of Technology and Economics Muegyetem, rakpart 1-3., Budapest, 1111, Hungary Department of Mathematics, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand Export Date: 28 April 2022 Correspondence Address: FehÉr, E.; MTA-BME Morphodynamics Research Group LA - English DB - MTMT ER - TY - JOUR AU - Frettlöh, D. AU - Glazyrin, A. AU - Lángi, Zsolt TI - Hexagon tilings of the plane that are not edge-to-edge JF - ACTA MATHEMATICA HUNGARICA J2 - ACTA MATH HUNG VL - 164 PY - 2021 IS - 2 SP - 341 EP - 349 PG - 9 SN - 0236-5294 DO - 10.1007/s10474-021-01155-5 UR - https://m2.mtmt.hu/api/publication/32162755 ID - 32162755 N1 - Export Date: 23 September 2021 Correspondence Address: Lángi, Z.; MTA-BME Morphodynamics Research Group and Department of Geometry, Egry József utca 1., Hungary; email: zlangi@math.bme.hu Funding details: 134199 Funding details: Magyar Tudományos Akadémia, MTA, BME FIKP-VĺZ Funding details: Universität Bielefeld Funding details: Innovációs és Technológiai Minisztérium Funding text 1: The first author is supported by the Research Centre for Mathematical Modelling (RCM2) of Bielefeld University. Funding text 2: The third author is partially supported by the NKFIH Hungarian Research Fund grant 134199, the János Bolyai Research Scholarship of the Hungarian Academy of Sciences, and grants BME FIKP-VĺZ and ÚNKP-20-5 New National Excellence Program by the Ministry of Innovation and Technology. Acknowledgements Funding text 3: The second author is partially supported by the Seed Grant Program of the College of Sciences of the University of Texas Rio Grande Valley. Funding Agency and Grant Number: Research Centre for Mathematical Modelling (RCM2) of Bielefeld University; College of Sciences of the University of Texas Rio Grande Valley; NKFIH Hungarian Research Fund [134199]; Hungarian Academy of SciencesHungarian Academy of Sciences; Ministry of Innovation and Technology [BME FIKP-VIZ, U NKP-20-5] Funding text: The first author is supported by the Research Centre for Mathematical Modelling (RCM2) of Bielefeld University.; The second author is partially supported by the Seed Grant Program of the College of Sciences of the University of Texas Rio Grande Valley.; The third author is partially supported by the NKFIH Hungarian Research Fund grant 134199, the J ' anos Bolyai Research Scholarship of the Hungarian Academy of Sciences, and grants BME FIKP-V ' IZ and ' U NKP-20-5 New National Excellence Program by the Ministry of Innovation and Technology. AB - An irregular vertex in a tiling by polygons is a vertex of one tile and belongs to the interior of an edge of another tile. In this paper we show that for any integer k >= 3, there exists a normal tiling of the Euclidean plane by convex hexagons of unit area with exactly k irregular vertices. Using the same approach we show that there are normal edge-to-edge tilings of the plane by hexagons of unit area and exactly k many n-gons (n > 6) of unit area. A result of Akopyan yields an upper bound for k depending on the maximal diameter and minimum area of the tiles. Our result complements this with a lower bound for the extremal case, thus showing that Akopyan's bound is asymptotically tight. LA - English DB - MTMT ER - TY - JOUR AU - Gáspár, Orsolya AU - Sajtos, István AU - Sipos, András Árpád TI - Friction as a geometric constraint on stereotomy in the minimum thickness analysis of circular and elliptical masonry arches JF - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES J2 - INT J SOLIDS STRUCT VL - 225 PY - 2021 PG - 18 SN - 0020-7683 DO - 10.1016/j.ijsolstr.2021.111056 UR - https://m2.mtmt.hu/api/publication/32274219 ID - 32274219 AB - Friction is much needed for the equilibrium of masonry arches as it transfers load between the voussoirs. In this paper, applying an analytical formulation of the problem, the angle of friction as a geometric constraint on the stereotomy (bricklaying pattern) is investigated to find the possible range of minimum thickness values of circular and elliptical masonry arches under static loads based on the lower bound theorem of limit state analysis. The Heymanian assumptions regarding material qualities are adopted; however, limited capacity in friction is accounted for. It has been shown earlier that considering stereotomies a-priori unknown, a considerably wide range of minimum thickness values is obtained for fixed loading and global geometry conditions. It is found that a stereotomy constrained by an angle of friction, characteristic of masonry, renders the effect of stereotomy on the minimum thickness value negligible because the range of minimum thickness values is significantly reduced in this case. Hence, the present study ultimately justifies the intuitive assumption of radial stereotomy, widely used in the literature, whenever the safety of masonry arches is studied. (C) 2021 The Author(s). Published by Elsevier Ltd. LA - English DB - MTMT ER - TY - CHAP AU - Gáspár, Orsolya AU - Sajtos, István AU - Sipos, András Árpád ED - Roca, P. ED - Pelà, L. ED - Molins, C. TI - Safe estimation of minimum thickness of circular masonry arches considering stereotomy and different rotational failure modes T2 - 12th International Conference on Structural Analysis of Historical Constructions, SAHC 2021 PB - International Centre for Numerical Methods in Engineering, CIMNE CY - Barcelona SN - 9788412322200 T3 - International Conference on Structural Analysis of Historical Constructions (SAHC), ISSN 2696-9157 PY - 2021 SP - 2229 EP - 2239 PG - 11 DO - 10.23967/sahc.2021.216 UR - https://m2.mtmt.hu/api/publication/31847313 ID - 31847313 N1 - Funding Agency and Grant Number: NKFIH Grant [124859]; FIKP grant of EMMI Funding text: The research was supported by the NKFIH Grant 124859 and the FIKP grant of EMMI in the frame of BME FIKP-VIZ. AB - Limit state analysis of masonry arches sets to assess the safety of the structure by determining the minimum thickness that just contains a thrust line. Based on the Heymanian assumptions regarding material qualities and the equilibrium approach to the static theorem it has been explicitly proven for semi-circular arches that both the thrust line and the resulting minimum thickness value is subject to stereotomy (brick or stone laying pattern), while present study demonstrates, that the latter statement holds for pointed-circular arches as well. This is not straightforward, since the number- and arrangement of the hinges at limit state vary subject to the geometry in case of pointed-circular arches, resulting a more complex problem. It is also explicitly shown, that stereotomy might also affect the corresponding (rotational) failure mode (for certain arch geometries). Stereotomy of an existing structure is not always known, hence it is relevant to search for a stereotomy related bounding value of minimum thickness for each of the various failure modes. The potential of the envelope of resultants as a thrust line (resulting from vertical stereotomy) leading to bounding value minimum thicknesses is discussed: as shown elsewhere it bounds the family of thrust lines, hence leads to an upper bound value of minimum thickness in case of semi-circular arches. It is demonstrated however, that this cannot be generalized for other rotational failure modes which occur for circular-pointed arches. The envelope of resultants does not necessarily lead to a bounding value of minimum thickness, and even if it does, it can be either an upper or a lower bound. However, it is found that the range of minimum thickness values is bounded in all possible failure mode types. The necessary conditions are provided for each. LA - English DB - MTMT ER - TY - CONF AU - Gáspár, Orsolya TI - Bauersfeld’s concept for the subdivision of the first built geodesic dome structure T2 - IASS 2020/21 Surrey Symposium PB - International Association for Shell and Spatial Structures (IASS) T3 - Proceedings of the IASS annual symposium, ISSN 2518-6582 ; 2020. PY - 2021 SP - 1 EP - 11 PG - 11 UR - https://m2.mtmt.hu/api/publication/31847302 ID - 31847302 AB - The metal lattice shell reinforcement of the first Planetarium in Jena, designed by Walther Bauersfeld, chief engineer of the Carl Zeiss AG in 1922 is considered the world’s first geodesic dome. In this study we demonstrate that the tessellation of the dome was much more delicate than previous studies suggested. As the dome was meant to be a temporary structure it was demolished shortly after its erection. Sources on the original design had been considered scarce: a few original pictures taken during construction and Bauersfeld’s handwritten notes, which are kept in the Zeiss Archives. These serve as primary resources for the present research. We show below that the unanimous assumption of previous studies, that the tessellation is identical to Buckminster Fuller’s icosahedral subdivision is neither supported by the existing documents and nor it is likely to be true. We present the results of a series of 3D reconstructions considering (a) Fuller’s icosahedral subdivision, (b) side-bisection and (c) an almost-equal area triangulation of the spherical surface found in Bauersfeld’s notes. These are compared to the existing photographs with the first resulting worst and the last resulting best match. It is also pointed out that the equal-area triangulation results a very smooth grid and contains relatively few different bars. This underlines the extraordinary skills of Bauersfeld as an engineer – who invented this tessellation 30-50 years prior to any theoretical studies on the optimal tessellation of geodesic domes. LA - English DB - MTMT ER - TY - JOUR AU - Hegyi, Dezső TI - Numerical stability analysis of arch-supported membrane roofs JF - STRUCTURES J2 - STRUCTURES VL - 29 PY - 2021 SP - 785 EP - 795 PG - 11 SN - 2352-0124 DO - 10.1016/j.istruc.2020.11.025 UR - https://m2.mtmt.hu/api/publication/31770965 ID - 31770965 N1 - Cited By :2 Export Date: 6 July 2022 LA - English DB - MTMT ER - TY - CONF AU - Hortobágyi, Tamás AU - Roszevák, Zsolt AU - Haris, István AU - Sajtos, István TI - Lyukacsos (anizotrop) téglaelem laboratóriumi és numerikus vizsgálata T2 - XXV. Nemzetközi Építéstudományi Online Konferencia – ÉPKO PY - 2021 SP - 72 EP - 79 PG - 8 UR - https://m2.mtmt.hu/api/publication/32063628 ID - 32063628 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Juhász, Károly Péter TI - A proposed evaluation method for three-point beam tests of fiber-reinforced concrete JF - JOURNAL OF TESTING AND EVALUATION J2 - J TEST EVAL VL - 49 PY - 2021 IS - 5 SP - 3838 EP - 3858 PG - 21 SN - 0090-3973 DO - 10.1520/JTE20190782 UR - https://m2.mtmt.hu/api/publication/32042382 ID - 32042382 N1 - Cited By :1 Export Date: 23 June 2022 CODEN: JTEVA Correspondence Address: Juhász, K.P.; Department of Mechanics, Műegyetem rkp. 3., Hungary; email: office@jkp.hu AB - The characteristic values of the material parameters used for structural design are usually determined from the mean and standard deviation of the material test results, and the design values are calculated from the characteristic values using the appropriate safety factor. However, if the standard deviation of the test data is high, the characteristic value is expected to be significantly lower than the mean value. In the case of fiber-reinforced concrete (FRC), the coefficient of variation is usually high, which can be attributed to the relatively small size of the specimen and the random location of the fibers. To overcome this limitation, this paper proposes a method that takes into account the number and location of the fibers when estimating the postcrack performance for a cracked cross section in a three-point notched bending beam tests. Test results of steel- and macrosynthetic FRC were evaluated using both the RILEM recommendations and the proposed method and are finally compared. Although the proposed method is more complex and the evaluation requires more effort than the existing method, it provides more repeatable material parameters, which exhibited a higher characteristic result. Copyright © 2020 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 LA - English DB - MTMT ER - TY - JOUR AU - Karádi, Dániel Tamás AU - Sipos, András Árpád AU - Halász, Marianna AU - Hliva, Viktor AU - Hegyi, Dezső TI - An elastic phenomenological material law of technical textile with a nonlinear shear behaviour JF - JOURNAL OF REINFORCED PLASTICS AND COMPOSITES J2 - J REINF PLAST COMP VL - 40 PY - 2021 IS - 19-20 SP - 759 EP - 769 PG - 11 SN - 0731-6844 DO - 10.1177/07316844211005842 UR - https://m2.mtmt.hu/api/publication/31940771 ID - 31940771 AB - In technical textile engineering, macro-level phenomenological modelling effectively describes the material's highly nonlinear behaviour. However, existing material laws concentrate on the normal stiffness in the orthotropic yarns and simplify the shear effect because of the two orders of magnitude difference between shear and normal stiffness. This article introduces an improved phenomenological model that includes nonlinear shear behaviour, and it determines the material parameters with a previously applied data fitting method for exponential functions. The nonlinear shear behaviour is valid for the elastic state, that is, at the service level of the loads. Time-dependent, cyclic loading or plastic behaviour is not considered. LA - English DB - MTMT ER - TY - JOUR AU - Karádi, Dániel Tamás AU - Hegyi, Dezső TI - An Extensive Review on the Viscoelastic-plastic and Fractural Mechanical Behaviour of ETFE Membranes JF - PERIODICA POLYTECHNICA ARCHITECTURE J2 - PERIOD POLYTECH ARCHITECT VL - 52 PY - 2021 IS - 2 SP - 121 EP - 134 PG - 14 SN - 0324-590X DO - 10.3311/PPar.18403 UR - https://m2.mtmt.hu/api/publication/32592511 ID - 32592511 LA - English DB - MTMT ER - TY - JOUR AU - Károlyi, György AU - Sipos, András Árpád TI - Soft impact of an elongated elasto-plastic missile JF - INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES J2 - INT J MECH SCI VL - 212 PY - 2021 PG - 10 SN - 0020-7403 DO - 10.1016/j.ijmecsci.2021.106804 UR - https://m2.mtmt.hu/api/publication/32214116 ID - 32214116 AB - Motivated by the grave consequences of an aircraft impact into robust engineering structures like nuclear power plants, we investigate the time-dependent reaction force during the impact of a crushing, elongated elasto-plastic missile into a robust elastic target. We derive a set of partial differential equations on a time-dependent domain to describe the impact. The simplest case of a homogeneous, cylindrical aircraft fuselage impacting a rigid target is solved analytically by using conformal mapping. After developing a numerical scheme for the case of an elastic target, we find that a simple dimensionless number, the damage potential, gives an accurate prediction of the impact force. The peak reaction force during the impact is found to exceed the initial impact force by up to 20%; hence the often applied strategy to estimate the peak force as the initial impact force is not a conservative approach. This effect is due to a resonant vibration in both the missile and the target. Predicted and computed parameters at which this counter-intuitive, resonance-like behavior occurs are shown to agree well. LA - English DB - MTMT ER - TY - CHAP AU - Köhserli, Mehmet AU - Várkonyi, Péter László ED - Snijder, H. H. Bert ED - De Pauw, Bart ED - van Alphen, Sander ED - Mengeot, Pierre TI - Vibration of structurally connected high-rise buildings under wind force T2 - IABSE Congress Ghent 2021 PB - International Association for Bridge and Structural Engineering (IABSE) CY - Zürich SN - 9781713836254 T3 - IABSE Congress Reports ; 21. PY - 2021 SP - 1598 EP - 1605 PG - 8 UR - https://m2.mtmt.hu/api/publication/32924413 ID - 32924413 N1 - Allplan; et al.; Greisch; Infrabel; Royal HaskoningDHV; TUC RAIL Conference code: 172892 Export Date: 8 July 2022 Correspondence Address: Köhserli, M.; Budapest University of Technology and EconomicsHungary; email: mehmetkohserli@edu.bme.hu AB - Cities are organized around various underlying networks but building structures do not follow this trend. The isolation of structural systems causes difficulties in the case of tall structures. We investigate the possibility of improving structural behaviour by organizing buildings into urban-scale structural networks, with focus on vortex-induced vibration. We review our recent work, in which randomly generated collections of high-rise buildings were examined by numerical simulation using a conceptual model of the network composed of springs and point masses. Here we examine the behaviour of a realistic collection of buildings, generated by considering the existing building stock and urban fabric of Midtown Manhattan. The new simulation results suggest that connections among the buildings would enable the application of significantly softer bracing systems. This finding suggests that urban-scale structural networks is a promising direction of urban development. © 2021 IABSE Congress, Ghent 2021: Structural Engineering for Future Societal Needs. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Lángi, Zsolt TI - Centering Koebe polyhedra via Möbius transformations JF - GROUPS GEOMETRY AND DYNAMICS J2 - GROUPS GEOMETRY DYNAMICS VL - 15 PY - 2021 IS - 1 SP - 197 EP - 221 PG - 25 SN - 1661-7207 DO - 10.4171/GGD/596 UR - https://m2.mtmt.hu/api/publication/32153529 ID - 32153529 N1 - Cited By :1 Export Date: 18 March 2024 Correspondence Address: Lángi, Z.; MTA-BME Morphodynamics Research Group, Egry József utca 1, Hungary; email: zlangi@math.bme.hu Funding details: Magyar Tudományos Akadémia, MTA Funding details: Ministry for Innovation and Technology Funding details: National Research, Development and Innovation Office, K134199, TKP2020 Funding text 1: 1 Partially supported by the Hungarian National Research, Development, and Innovation Office Research Grant K134199 and Grant TKP2020 IE Grant BME Water Sciences & Disaster Prevention, the UNKP-20-5 New National Excellence Program of the Ministry of Innovation and Technology, and the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. AB - A variant of the Circle Packing Theorem states that the combinatorial class of any convex polyhedron contains elements, called Koebe polyhedra, midscribed to the unit sphere centered at the origin, and that these representatives are unique up to Möbius transformations of the sphere. Motivated by this result, various papers investigate the problem of centering spherical configurations under Möbius transformations. In particular, Springborn proved that for any discrete point set on the sphere there is a Möbius transformation that maps it into a set whose barycenter is the origin, which implies that the combinatorial class of any convex polyhedron contains an element midsribed to a sphere with the additional property that the barycenter of the points of tangency is the center of the sphere. This result was strengthened by Baden, Krane and Kazhdan who showed that the same idea works for any reasonably nice measure defined on the sphere. The aim of the paper is to show that Springborn’s statement remains true if we replace the barycenter of the tangency points by many other polyhedron centers. The proof is based on the investigation of the topological properties of the integral curves of certain vector fields defined in hyperbolic space. We also show that most centers of Koebe polyhedra cannot be obtained as the center of a suitable measure defined on the sphere. LA - English DB - MTMT ER - TY - JOUR AU - Lévay, Sára AU - Fischer, D. AU - Stannarius, R. AU - Somfai, Ellák AU - Börzsönyi, Tamás AU - Brendel, L. AU - Török, János TI - Interacting jammed granular systems JF - PHYSICAL REVIEW E: COVERING STATISTICAL NONLINEAR BIOLOGICAL AND SOFT MATTER PHYSICS (2016-) J2 - PHYSICAL REVIEW E VL - 103 PY - 2021 IS - 4 PG - 8 SN - 2470-0045 DO - 10.1103/PhysRevE.103.042901 UR - https://m2.mtmt.hu/api/publication/31991964 ID - 31991964 LA - English DB - MTMT ER - TY - JOUR AU - Madani, Mahnoush AU - Maleki, Maniya AU - Török, János AU - Shaebani, M. Reza TI - Evolution of shear zones in granular packings under pressure JF - SOFT MATTER J2 - SOFT MATTER VL - 17 PY - 2021 IS - 7 SP - 1814 EP - 1820 PG - 7 SN - 1744-683X DO - 10.1039/D0SM01768J UR - https://m2.mtmt.hu/api/publication/31937866 ID - 31937866 N1 - Export Date: 1 June 2021 CODEN: SMOAB Correspondence Address: Shaebani, M.R.; Department of Theoretical Physics & Center for Biophysics, Germany; email: shaebani@lusi.uni-sb.de Export Date: 2 June 2021 CODEN: SMOAB Correspondence Address: Shaebani, M.R.; Department of Theoretical Physics & Center for Biophysics, Germany; email: shaebani@lusi.uni-sb.de LA - English DB - MTMT ER - TY - JOUR AU - Marótzy, Katalin AU - Halmos, Balázs AU - Armuth, Miklós AU - Hegyi, Dezső TI - Az igazfalvi református templom JF - DOLGOZATOK AZ ERDÉLYI MÚZEUM ÉREM- ÉS RÉGISÉGTÁRÁBÓL J2 - DOLG ERDÉLYI MÚZ ÉREM- ÉS RÉGISÉGTÁRÁBÓL PY - 2021 SN - 1842-5089 UR - https://m2.mtmt.hu/api/publication/33708014 ID - 33708014 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Murase, Y. AU - Jo, H.-H. AU - Török, János AU - Kertész, J. AU - Kaski, K. TI - Deep Learning Exploration of Agent-Based Social Network Model Parameters JF - FRONTIERS IN BIG DATA J2 - FRONT BIG DATA VL - 4 PY - 2021 PG - 12 SN - 2624-909X DO - 10.3389/fdata.2021.739081 UR - https://m2.mtmt.hu/api/publication/32869102 ID - 32869102 N1 - RIKEN Center for Computational Science, Kobe, Japan Department of Physics, The Catholic University of Korea, Bucheon, South Korea Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest, Hungary Department of Network and Data Science, Central European University, Vienna, Austria MTA-BME Morphodynamics Research Group, Budapest University of Technology and Economics, Budapest, Hungary Department of Computer Science, Aalto University, Espoo, Finland The Alan Turing Institute, British Library, London, United Kingdom Export Date: 9 June 2022 Correspondence Address: Jo, H.-H.; Department of Physics, South Korea; email: h2jo@catholic.ac.kr Funding details: 871042 Funding details: 952026 Funding details: Horizon 2020 Framework Programme, H2020 Funding details: Japan Society for the Promotion of Science, KAKEN, 18H03621, 21K03362 Funding details: Aalto-Yliopisto Funding details: National Research Foundation of Korea, NRF Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH, OTKA K129124 Funding details: Kementerian Pendidikan Malaysia, KPM, NRF-2018R1D1A1A09081919 Funding text 1: YM acknowledges support from Japan Society for the Promotion of Science (JSPS) (JSPS KAKENHI; Grant No. 18H03621 and Grant No. 21K03362). H-HJ was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1D1A1A09081919). JT was supported by NKFIH (Grant Nos. OTKA K129124). JK was partially supported by EU H2020 Humane AI-net (Grant #952026) and EU H2020 SoBigData++ (Grant #871042). KK acknowledges support from EU H2020 SoBigData++ project and Nordforsk’s Nordic Programme for Interdisciplinary Research project “The Network Dynamics of Ethnic Integration”. Funding text 2: YM, H-HJ, JT, and JK are thankful for the hospitality of Aalto University. This research used computational resources of the supercomputer Fugaku provided by the RIKEN Center for Computational Science. AB - Interactions between humans give rise to complex social networks that are characterized by heterogeneous degree distribution, weight-topology relation, overlapping community structure, and dynamics of links. Understanding these characteristics of social networks is the primary goal of their research as they constitute scaffolds for various emergent social phenomena from disease spreading to political movements. An appropriate tool for studying them is agent-based modeling, in which nodes, representing individuals, make decisions about creating and deleting links, thus yielding various macroscopic behavioral patterns. Here we focus on studying a generalization of the weighted social network model, being one of the most fundamental agent-based models for describing the formation of social ties and social networks. This generalized weighted social network (GWSN) model incorporates triadic closure, homophilic interactions, and various link termination mechanisms, which have been studied separately in the previous works. Accordingly, the GWSN model has an increased number of input parameters and the model behavior gets excessively complex, making it challenging to clarify the model behavior. We have executed massive simulations with a supercomputer and used the results as the training data for deep neural networks to conduct regression analysis for predicting the properties of the generated networks from the input parameters. The obtained regression model was also used for global sensitivity analysis to identify which parameters are influential or insignificant. We believe that this methodology is applicable for a large class of complex network models, thus opening the way for more realistic quantitative agent-based modeling. © Copyright © 2021 Murase, Jo, Török, Kertész and Kaski. LA - English DB - MTMT ER - TY - JOUR AU - Or, Yizhar AU - Várkonyi, Péter László TI - Experimental Verification of Stability Theory for a Planar Rigid Body With Two Unilateral Frictional Contacts JF - IEEE TRANSACTIONS ON ROBOTICS J2 - IEEE T ROBOT VL - 37 PY - 2021 IS - 5 SP - 1634 EP - 1648 PG - 15 SN - 1552-3098 DO - 10.1109/TRO.2021.3064871 UR - https://m2.mtmt.hu/api/publication/32218766 ID - 32218766 LA - English DB - MTMT ER - TY - JOUR AU - Pál, Gergő AU - Domokos, Gábor AU - Kun, Ferenc TI - Curvature flows, scaling laws and the geometry of attrition under impacts JF - SCIENTIFIC REPORTS J2 - SCI REP VL - 11 PY - 2021 IS - 1 SN - 2045-2322 DO - 10.1038/s41598-021-00030-1 UR - https://m2.mtmt.hu/api/publication/32463947 ID - 32463947 N1 - Department of Theoretical Physics, Doctoral School of Physics, Faculty of Science and Technology, University of Debrecen, P.O. Box 400, Debrecen, 4002, Hungary Institute of Nuclear Research (Atomki), P.O. Box 51, Debrecen, 4001, Hungary Department of Mechanics, Materials and Structures, Budapest University of Technology and Economics, Műegyetem rkp. 3., K261, Budapest, 1111, Hungary MTA-BME Morphodynamics Reserarch Group, Műegyetem rkp. 3., K261, Budapest, 1111, Hungary Cited By :1 Export Date: 10 February 2022 Correspondence Address: Kun, F.; Department of Theoretical Physics, P.O. Box 400, Hungary; email: ferenc.kun@science.unideb.hu AB - Impact induced attrition processes are, beyond being essential models of industrial ore processing, broadly regarded as the key to decipher the provenance of sedimentary particles. Here we establish the first link between microscopic, particle-based models and the mean field theory for these processes. Based on realistic computer simulations of particle-wall collision sequences we first identify the well-known damage and fragmentation energy phases, then we show that the former is split into the abrasion phase with infinite sample lifetime (analogous to Sternberg's Law) at finite asymptotic mass and the cleavage phase with finite sample lifetime, decreasing as a power law of the impact velocity (analogous to Basquin's Law). This splitting establishes the link between mean field models (curvature-driven partial differential equations) and particle-based models: only in the abrasion phase does shape evolution emerging in the latter reproduce with startling accuracy the spatio-temporal patterns (two geometric phases) predicted by the former. LA - English DB - MTMT ER - TY - JOUR AU - Pongó, Tivadar AU - Stiga, Viktória AU - Török, János AU - Lévay, Sára AU - Szabó, Balázs AU - Stannarius, R. AU - Hidalgo, R.C. AU - Börzsönyi, Tamás TI - Flow in an hourglass: Particle friction and stiffness matter JF - NEW JOURNAL OF PHYSICS J2 - NEW J PHYS VL - 23 PY - 2021 IS - 2 PG - 17 SN - 1367-2630 DO - 10.1088/1367-2630/abddf5 UR - https://m2.mtmt.hu/api/publication/31919027 ID - 31919027 LA - English DB - MTMT ER - TY - CHAP AU - Sajtos, István AU - Sipos, András Árpád AU - Gáspár, Orsolya ED - Roca, P. ED - Pelà, L. ED - Molins, C. TI - General thurst surface of masonry domes T2 - 12th International Conference on Structural Analysis of Historical Constructions, SAHC 2021 PB - International Centre for Numerical Methods in Engineering, CIMNE CY - Barcelona SN - 9788412322200 T3 - International Conference on Structural Analysis of Historical Constructions (SAHC), ISSN 2696-9157 PY - 2021 PG - 12 DO - 10.23967/sahc.2021.120 UR - https://m2.mtmt.hu/api/publication/32458382 ID - 32458382 AB - Masonry domes are shell-like structures with a no-tension type material behavior [1]. The dome geometry, material behavior and the type of the loading define how the dome balances the load. It is known and proved that the dome could balance the load only by forces, without bending moment but cracks may appear since the material does not resist tension. The surface where the balancing forces are acting is called the thrust surface. The paper introduces the idea of the general thrust surface. It is such a balancing surface where the forces are not acting in the tangent plane of the thrust surface and otherwise it is moment free. A method is shown how to find the general thrust surface for a cracked spherical masonry dome. Numerical example illustrates the usefulness and effectiveness of the proposed method to determine the general thrust surface of a spherical dome when radial stereotomy is considered. By the help of the proposed model the safety of the more than 350 years old, cracked dome of Gol Gumbaz, India can be proofed. LA - English DB - MTMT ER - TY - JOUR AU - Shaebani, M.R. AU - Török, János AU - Maleki, M. AU - Madani, M. AU - Harrington, M. AU - Rice, A. AU - Losert, W. TI - Gravity Governs Shear Localization in Confined Dense Granular Flows JF - PHYSICAL REVIEW LETTERS J2 - PHYS REV LETT VL - 127 PY - 2021 IS - 27 SN - 0031-9007 DO - 10.1103/PhysRevLett.127.278003 UR - https://m2.mtmt.hu/api/publication/32678311 ID - 32678311 N1 - Export Date: 16 February 2022 CODEN: PRLTA AB - The prediction of flow profiles of slowly sheared granular materials is a major geophysical and industrial challenge. Understanding the role of gravity is particularly important for future planetary exploration in varying gravitational environments. Using the principle of minimization of energy dissipation, and combining experiments and variational analysis, we disentangle the contributions of the gravitational acceleration, confining pressure, and layer thickness on shear strain localization induced by moving fault boundaries at the bottom of a granular layer. The flow profile is independent of the gravity for geometries with a free top surface. However, under a confining pressure or if the sheared layer withstands the weight of the upper layers, increasing gravity promotes the transition from closed shear zones buried in the bulk to open ones that intersect the top surface. We show that the center position and width of the shear zone and the axial angular velocity at the top surface follow universal scaling laws when properly scaled by the gravity, applied pressure, and layer thickness. Our finding that the flow profiles lie on a universal master curve opens the possibility to predict the quasistatic shear flow of granular materials in varying gravitational environments. LA - English DB - MTMT ER - TY - JOUR AU - Sipos, András Árpád AU - Domokos, Gábor AU - Török, János TI - Particle size dynamics in abrading pebble populations JF - EARTH SURFACE DYNAMICS J2 - E SURF DYN VL - 9 PY - 2021 IS - 2 SP - 235 EP - 251 PG - 17 SN - 2196-6311 DO - 10.5194/esurf-9-235-2021 UR - https://m2.mtmt.hu/api/publication/31890542 ID - 31890542 AB - Abrasion of sedimentary particles in fluvial and eolian environments is widely associated with collisions encountered by the particle. Although the physics of abrasion is complex, purely geometric models recover the course of mass and shape evolution of individual particles in low- and middle-energy environments (in the absence of fragmentation) remarkably well. In this paper, we introduce the first model for the collision-driven collective mass evolution of sedimentary particles. The model utilizes results of the individual, geometric abrasion theory as a collision kernel; following techniques adopted in the statistical theory of coagulation and fragmentation, the corresponding Fokker–Planck equation is derived. Our model uncovers a startling fundamental feature of collective particle size dynamics: collisional abrasion may, depending on the energy level, either focus size distributions, thus enhancing the effects of size-selective transport, or it may act in the opposite direction by dispersing the distribution. LA - English DB - MTMT ER - TY - JOUR AU - Szabó, Simon AU - Kövesdi, Andrea AU - Vasáros, Zsolt AU - O. Csicsely, Ágnes Magdolna AU - Hegyi, Dezső TI - The cause of damage and failure of the Mud-brick vault of the Khan in New-Gourna JF - ENGINEERING FAILURE ANALYSIS J2 - ENG FAIL ANAL VL - 128 PY - 2021 PG - 21 SN - 1350-6307 DO - 10.1016/j.engfailanal.2021.105567 UR - https://m2.mtmt.hu/api/publication/32114285 ID - 32114285 N1 - Department of Mechanics, Materials & Structures, Budapest University of Technology and Economics, Budapest, Hungary Department of Industrial and Agricultural Building Design, Budapest University of Technology and Economics, Budapest, Hungary Cited By :2 Export Date: 9 June 2022 CODEN: EFANE Correspondence Address: Hegyi, D.; Department of Mechanics, Hungary; email: hegyi.dezso@szt.bme.hu Funding details: Innovációs és Technológiai Minisztérium, TKP2020 Funding details: National Research, Development and Innovation Office, BME IE-VIZ TKP2020 Funding text 1: The research reported in this paper and carried out at the Budapest University of Technology and Economics was supported by the “TKP2020, Institutional Excellence Program” of the National Research, Development and Innovation Office in the field of Water Sciences & Disaster Prevention ( BME IE-VIZ TKP2020 ). Funding text 2: The research program was supported by the ÚNKP-19-3 and the ÚNKP-19-4 New National Excellence Program of the Ministry for Innovation and Technology. AB - New Gourna, Egypt became an iconic place of mud-brick architecture in the middle of the 20th century as a result of the work of Hassan Fathy. In the dry climate of Egypt, mud-brick is an almost perfect building material, but the change in the environmental circumstances have caused damage to the structures. The present study aims to find the root of the problems to give chance to find suggestions for reliable strengthening. The paper focuses on one of the central buildings of New Gourna, the so-called Khan, designed by Hassan Fathy. The structure of the arcade of the Khan is modeled by advanced Finite Element method to simulate gradual deformation and failure with special attention to recent renovations that seem to have turned the condition of the structures even worse. As there are no experimental tests on the real materials, possible material models were collected for the analysis, and the most feasible result, which fits the visible failure was accepted. According to the analysis, the failure of the structure is caused by the wetting of the mud mortar layer between the limestone elements of the plinth. There were no significant signs of weakness in the foundation. The wetting of the mud mortar in the plinth is caused by the dramatical change in the ground-water level caused by the building of the Aswan High Dam and the dramatic change in the amount of wastewater caused by the increased population in New Gourna. LA - English DB - MTMT ER - TY - JOUR AU - Ther, Tamás AU - Kollár, László Péter TI - Dynamical similarity of multi-block catenary arches and rocking blocks subjected to horizontal base excitation JF - NONLINEAR DYNAMICS J2 - NONLINEAR DYNAM VL - 104 PY - 2021 IS - 3 SP - 2099 EP - 2116 PG - 18 SN - 0924-090X DO - 10.1007/s11071-021-06415-1 UR - https://m2.mtmt.hu/api/publication/32037102 ID - 32037102 N1 - Export Date: 30 May 2022 CODEN: NODYE Correspondence Address: Ther, T.; Department of Mechanics, Műegyetem rkp. 3, Hungary; email: ther.tamas@epk.bme.hu AB - In this paper, the dynamical similarity of multi-block catenary arches and columns is discussed, which can be used for the simplified design of rocking arches. The basic hypothesis is that the dynamic response of multi-block arches and columns is similar when the shape of the arch follows the thrust line, i.e. it is a catenary arch. It is validated numerically that the responses of slender catenary arches are safe and reliable approximations of those of not slender arches and then that the overturning acceleration (response) spectra of rigid, slender monolithic blocks can be directly applied for catenary arches. The similarity is based on two parameters, on the limit peak ground acceleration (under which the structure will not move at all) and on the frequency parameter (defined by Housner for rigid blocks). LA - English DB - MTMT ER -