TY - JOUR AU - Lewinski, T AU - Rozványi, György TI - Exact analytical solutions for some popular benchmark problems in topology optimization II: three-sided polygonal supports JF - STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION J2 - STRUCT MULTIDISCIP OPTIM VL - 33 PY - 2007 IS - 4-5 SP - 337 EP - 349 PG - 13 SN - 1615-147X DO - 10.1007/s00158-007-0093-7 UR - https://m2.mtmt.hu/api/publication/2628674 ID - 2628674 N1 - Megjegyzés-24051911 : Multidisciplinary; Mechanics AB - In an earlier paper (Rozvany, Struct Optim 15:42-48, 1998), the second author summarized known analytical solutions for some popular benchmark problems in topology optimization. In this, and in some subsequent papers, further exact optimal topologies are derived for least-weight, stress-controlled trusses, with load and support conditions that are frequently used in benchmark examples for numerical methods in topology optimization. LA - English DB - MTMT ER - TY - JOUR AU - Bagi, Katalin TI - Discussion of the paper "Tensorial form definitions of discrete mechanical quantities for granular assemblies" [M. Satake, Int. J. Solids and Structures 2004, 41(21), pp. 5775-5791] JF - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES J2 - INT J SOLIDS STRUCT VL - 43 PY - 2006 IS - 9 SP - 2840 EP - 2844 PG - 5 SN - 0020-7683 DO - 10.1016/j.ijsolstr.2006.01.002 UR - https://m2.mtmt.hu/api/publication/2629242 ID - 2629242 AB - The aim of this Discussion is to clarify a terminological issue in a previous IJSS paper. (c) 2006 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - BOOK AU - Popper, György TI - Some Concepts of Functional Analysis using Mathematica ET - 0 PB - Műegyetemi Kiadó CY - Budapest PY - 2006 SP - 94 UR - https://m2.mtmt.hu/api/publication/2624269 ID - 2624269 LA - English DB - MTMT ER - TY - JOUR AU - Hegyi, Dezső AU - Sajtos, István AU - Geiszter, Gy AU - Hincz, Krisztián TI - Eight-node quadrilateral double-curved surface element for membrane analysis JF - COMPUTERS & STRUCTURES J2 - COMPUT STRUCT VL - 84 PY - 2006 IS - 31-32 SP - 2151 EP - 2158 PG - 8 SN - 0045-7949 DO - 10.1016/j.compstruc.2006.08.046 UR - https://m2.mtmt.hu/api/publication/2619344 ID - 2619344 AB - The dynamic relaxation method is applied to membrane analysis using an eight-node quadrilateral element. The element uses second order shape functions to approximate the geometry of the structure. The element is based on the element of Gosling and Lewis [Gosling PD, Lewis WJ. Optimal structural membranes—I. Formulation of a curved quadrilateral element for surface definition. Comp Struct 1996;61:871–83]. They used a finite element approach. In this paper exact tensorial calculation is used to determine the exact deformation between the deformation-free state and the actual state. #?# 2006 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - CHAP AU - Hincz, Krisztián TI - Analysis of Membrane Structures Using Visco-Elastic Material Model T2 - IABSE Symposium on Responding to Tomorrow's Challenges in Structural Engineering PB - International Association for Bridge and Structural Engineering (IABSE) CY - Zürich SN - 9783857481147 T3 - IABSE reports ; 92. PY - 2006 SP - 1 EP - 7 PG - 7 UR - https://m2.mtmt.hu/api/publication/1792965 ID - 1792965 LA - English DB - MTMT ER - TY - CHAP AU - Gáspár, Zsolt ED - Kollár, Lajos TI - A katasztrófaelmélet alkalmazása a szerkezetek stabilitásvizsgálatában. 4. fejezet T2 - A mérnöki stabilitáselmélet különleges problémái PB - Akadémiai Kiadó CY - Budapest SN - 9789630581462 PY - 2006 SP - 158 EP - 276 PG - 119 UR - https://m2.mtmt.hu/api/publication/1779958 ID - 1779958 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Pomezanski, Vanda Olimpia ED - Topping, BHV ED - Montero, G ED - Montenegro, R TI - Numerical Methods to Avoid Topological Singularities T2 - Proceedings of the Eighth International Conference on Computational Structures Technology PB - Civil-Comp Press CY - Stirling SN - 1905088078 PY - 2006 PG - 14 DO - 10.4203/ccp.83.211 UR - https://m2.mtmt.hu/api/publication/1707689 ID - 1707689 AB - Summary One of the most severe computational difficulties in finite element (FE) based topology optimization is caused by solid (or "black") ground elements connected only through a corner node. This configuration may appear in checkerboard patterns, diagonal element chains or as isolated hinges. Corner contacts in nominally optimal topologies are caused by discretization errors associated with simple (e.g. four-node) elements (e.g. Sigmund and Petersson [1]), which grossly overestimate the stiffness of corner regions with stress concentrations. In fact, it was shown by Gaspar et al. [2] that both checkerboard patterns and diagonal element chains may give an infinite compliance, if the latter is calculated by an exact analytical method. This makes them the worst possible solution, if an exact analysis is used in compliance minimization. Corner contacts may be suppressed by (a) a more accurate FE analysis of the ground elements, where the process may use several simple FEs per ground element (e.g. Rozvany and Zhou [3]), or higher order elements (Sigmund and Petersson [1]). Disadvantages of this approach are * greatly increased DOF for a given number of ground elements and * some diagonal chains remaining in the solution (Gaspar et al. [4]). (b) Modification of the original problem by using geometrical constraints or "diffused" sensitivities (filters), e.g. perimeter control (Haber and Bendsoe [5]) or filtering (e.g. Sigmund [6]) changes the original topology optimization problem and this usually results in a lower resolution, which may, in some cases, be somewhat nonoptimal in terms of the original problem [2]. (c) Employing a constraint preventing corner contacts directly, here the "corner contact function" (CCF) with a high value for corner contacts and a low value for any other configuration around a corner node is an additional constraint (e.g. Poulsen [7]). (d) Correcting selectively the discretization errors by appropriately penalizing corner contacts, in this case the CCF is an additional term in the objective function representing penalty for corner contacts. The approach (d) seems to be the most rational, because it rectifies the discretization errors, which lower incorrectly the value of the objective function (e.g. compliance). The proposed method is particularly effective in combination with the SIMP method, since the latter is a penalization method in its original form, and requires only a minor modification for corner contact control (CO-SIMP). An early corner contact function was suggested by Bendsoe et al. [8]. Defining and employing new CCFs, continuous functions which have a high value for corner contacts and a low value for any other configuration around a node, as an objective a new mathematical programming process CO-SIMP was developed [9]. The CO-SIMP method for the case of Michell's cantilever generates a similar result as the exact solution. The development of the CCFs properties, the numerical method, the modified SIMP algorithm and extensive numerical examples are included in the paper. LA - English DB - MTMT ER - TY - CHAP AU - Rozványi, György AU - Pomezanski, Vanda Olimpia AU - Querin, OM AU - Gáspár, Zsolt AU - Lógó, János ED - Bendsoe, M ED - Olhoff, N ED - Sigmond, O TI - Some Basic Issues of Topology Optimization T2 - IUTAM Symposium on Topological Design Optimization of Structures, Machines and Materials PB - Springer New York CY - Berlin SN - 9781402047299 T3 - SOLID MECHANICS AND ITS APPLICATIONS ; 137. PY - 2006 SP - 77 EP - 86 PG - 10 DO - 10.1007/1-4020-4752-5_8 UR - https://m2.mtmt.hu/api/publication/1707680 ID - 1707680 N1 - Research Group: Computational Structural Mechanics, Hungarian Academy of Sciences, Budapest University of Technology and Economics, Müegyetem rkpt 3, Kmf. 35, H-1521 Budapest, Hungary School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom Correspondence Address: Rozvany, G.I.N.; Research Group: Computational Structural Mechanics, Müegyetem rkpt 3, Kmf. 35, H-1521 Budapest, Hungary LA - English DB - MTMT ER - TY - CHAP AU - Iványi, Péter ED - Topping, BHV ED - Montero, G ED - Montenegro, R TI - The use of the medial-axis construction in the design of cable-membrane structures T2 - Proceedings of the Eighth International Conference on Computational Structures Technology PB - Civil-Comp Press CY - Stirling SN - 1905088078 PY - 2006 SP - 1 EP - 13 PG - 13 UR - https://m2.mtmt.hu/api/publication/1669499 ID - 1669499 LA - English DB - MTMT ER - TY - JOUR AU - Bagi, Katalin TI - Analysis of microstructural strain tensors for granular assemblies JF - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES J2 - INT J SOLIDS STRUCT VL - 43 PY - 2006 IS - 10 SP - 3166 EP - 3184 PG - 19 SN - 0020-7683 DO - 10.1016/j.ijsolstr.2005.07.016 UR - https://m2.mtmt.hu/api/publication/208965 ID - 208965 LA - English DB - MTMT ER -