@article{MTMT:34535659, title = {Mechanical Studies of Subperiosteal Implants}, url = {https://m2.mtmt.hu/api/publication/34535659}, author = {Kulcsár, Klaudia and Zsoldos, Ibolya}, doi = {10.3311/PPme.23706}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {2024}, unique-id = {34535659}, issn = {0324-6051}, abstract = {When designing subperiosteal implants, mechanical testing of the implant and abutment is inevitable. Subperiosteal implants and their abutments are medical devices made to order, so each implant requires a separate design, since each patient has a different bone surface, for which the implant must be designed. For the mechanical testing of subperiosteal implants, a new test apparatus was constructed, on which mechanical simulations were carried out, the subperiosteal implants were tested together with their abutments. In addition to the finite element analysis simulation, the test apparatus can also be used to determine how much force is generated by the chewing force on the subperiosteal implant and its abutment as a result of the chewing mechanism.}, year = {2024}, eissn = {1587-379X} } @article{MTMT:34692739, title = {Effect of Processing Parameters and Wall Thickness on the Strength of Injection Molded Products}, url = {https://m2.mtmt.hu/api/publication/34692739}, author = {Horváth, Szabolcs and Kovács, József Gábor}, doi = {10.3311/PPme.24068}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {68}, unique-id = {34692739}, issn = {0324-6051}, abstract = {Polymer materials are getting more and more attention in key industries like the automotive, aerospace, and electrical industries. A long lifetime with sustainable recycling is expected; great results are possible thanks to modern material engineering. Finding a suitable material for the purpose and the appropriate methods to test the required functionality is essential. An important mechanical loading tests is the tensile test. Although the ISO 527-1:2019 standard uses different tensile specimen geometries, none of those consider the possible thickness variations of the injection molded parts. If thickness is reduced to 1 mm, the solid layer will be dominant, which makes the properties of the tensile specimen process-dependent instead of material-dependent. In today's industry, it is crucial to examine both the material and the details of the processing technology together, given the downsizing effect.}, year = {2024}, eissn = {1587-379X}, pages = {78-84}, orcid-numbers = {Kovács, József Gábor/0000-0002-7391-7085} } @article{MTMT:34569161, title = {Investigation of 3D Printed Underwater Thruster Propellers Using CFD and Structural Simulations}, url = {https://m2.mtmt.hu/api/publication/34569161}, author = {Kiss-Nagy, Krisztián and Simongáti, Győző and Ficzere, Péter}, doi = {10.3311/PPme.23795}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {68}, unique-id = {34569161}, issn = {0324-6051}, abstract = {Unmanned Surface Vehicles (USV) and Autonomous or Remotely Operated Underwater vehicles (AUV, ROV) are developing and spreading rapidly in various industries. A common feature of these vehicles is that they are propelled by small plastic (or metal) propellers in most cases. Additive manufacturing can offer an excellent opportunity for rapid prototyping and the development of new models. This paper aims to investigate the fundamental aspects to be considered in the geometric design and manufacturing of small (diameter less than 100 mm) PLA (Polylactic acid) propellers 3D-printed using Fused Filament Fabrication (FFF) technology. In-service deformation of 3D-printed PLA ducted propellers with average geometry was investigated to determine the effect on the thrust and torque on the blades. For this purpose, one-directional FSI (Fluid Solid Interaction) simulations were performed using CFD (Computational Fluid Dynamics) and structural simulations. The propeller CAD geometries were generated using an in-house MATLAB script. The variable parameters of each version are the thickness, skew, and rake of the propeller blades. For the structural simulations, it was considered that the material properties of PLA parts printed with FFF technology depend on the print orientation. The results of the simulations show that except for extreme geometries (e.g., thin blades, skew, or rake more than 10 degrees), the deformation of small PLA ducted propellers is not significant. CFD studies of the deformed geometries have shown that the resulting deformation has no significant effect on the thrust and torque of the propeller and thruster.}, keywords = {Rapid prototyping; vehicle; CFD; 3D-printed propeller; PLA propellers}, year = {2024}, eissn = {1587-379X}, pages = {70-77}, orcid-numbers = {Ficzere, Péter/0000-0003-3207-5501} } @article{MTMT:34531765, title = {Investigation of the Bending Properties of Ex situ Functional Metal Foams}, url = {https://m2.mtmt.hu/api/publication/34531765}, author = {Pados, Gábor and Kemény, Alexandra and Károly, Dóra and Orbulov, Imre Norbert}, doi = {10.3311/PPme.23707}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {68}, unique-id = {34531765}, issn = {0324-6051}, abstract = {In each industry, compromises have to be made when choosing materials. Lower-density materials have a significant advantage in the automotive sector, especially due to rising fuel prices, since weight reduction can lower overall fuel consumption. The advantageous properties of metal foams, such as low density, high specific strength, and excellent energy absorption, should be researched and exploited in as many areas and ways as possible. This research aims to perform and evaluate the bending tests of ex situ functional metal foams: aluminum alloy matrix (AlSi7Mg) was used, which was filled with Ø2.5–3.0 mm lightweight expanded clay aggregate particles and surrounded by thin-walled aluminum tubes (AlMgSi0.5) with a wall thickness of 2 mm and an outer diameter of Ø32 mm. Empty tubes, foam-filled tubes (with and without structural epoxy adhesive) and metal matrix syntactic foams were compared based on their flexural strength and energy absorption capacity. Quasi-static three-point bend tests were carried out up to 25 mm deflection. The foam-filled tubes with epoxy adhesive showed an average of 6% increase in flexural strength compared to the foam-filled tubes without adhesive and a 145% increase compared to the metal matrix syntactic foams.}, year = {2024}, eissn = {1587-379X}, pages = {63-69}, orcid-numbers = {Kemény, Alexandra/0000-0001-8239-2252; Orbulov, Imre Norbert/0000-0002-5358-0630} } @article{MTMT:34495646, title = {Predicting Concentration Fluctuations of Locally Emitted Air Pollutants in Urban-like Geometry Using Deep Learning}, url = {https://m2.mtmt.hu/api/publication/34495646}, author = {Papp, Bálint and Kristóf, Gergely}, doi = {10.3311/PPme.23391}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {68}, unique-id = {34495646}, issn = {0324-6051}, abstract = {The accurate quantification of concentration fluctuations is crucial when evaluating the exposure to toxic, infectious, reactive, flammable, or explosive substances, as well as for the estimation of odor nuisance. However, in the field of Computational Fluid Dynamics (CFD), the industry currently relies predominantly on steady-state RANS turbulence models for simulating near-field pollutant dispersion, which are only capable of producing the time-averaged concentration field. This paper presents a regression relationship for calculating the standard deviation of the local concentration based on the mean concentration and the downstream distance from a point source, over a city-like surface, in the case of the wind direction perpendicular to the streets. The desired peak values and other statistical characteristics can be predicted by assuming a gamma distribution which is fitted based on the average and standard deviation. To obtain the regression function, a deep neural network model was used. The model was trained using time-resolved concentration data obtained from wind tunnel experiments. The validation results show that the concentration fluctuations predicted by the DNN-based model are in satisfactory agreement with the measurement data in terms of the skewness, the kurtosis, the median, and the peak concentrations. Furthermore, the present paper suggests a workflow for estimating the concentration fluctuations based on RANS CFD results, as well as recommendations for generating further training data for specific applications.}, keywords = {simulation; Environment; dispersion; fluid dynamics; CFD; Urban air quality}, year = {2024}, eissn = {1587-379X}, pages = {44-52}, orcid-numbers = {Papp, Bálint/0000-0001-8043-5271; Kristóf, Gergely/0000-0001-7572-6875} } @article{MTMT:34273364, title = {Investigation of Spinodal Decomposition in Isothermally Heat Treated LDX 2101 type Duplex Stainless Steel at 475 °C}, url = {https://m2.mtmt.hu/api/publication/34273364}, author = {Berecz, Tibor and Mészáros, István and Jenei, Péter}, doi = {10.3311/PPme.23385}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {68}, unique-id = {34273364}, issn = {0324-6051}, year = {2024}, eissn = {1587-379X}, pages = {38-43}, orcid-numbers = {Berecz, Tibor/0000-0001-9632-8120; Jenei, Péter/0000-0001-5187-9893} } @article{MTMT:34454253, title = {Joining of EN AW 6060 Pipes by Plastic Forming}, url = {https://m2.mtmt.hu/api/publication/34454253}, author = {Kovács, Péter Zoltán}, doi = {10.3311/PPme.23005}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {2023}, unique-id = {34454253}, issn = {0324-6051}, abstract = {The article deals with an innovative, but not widely used type of joining of aluminum pipes through experiments. The joints are formed by plastic forming. The process is carried out in one step using the principle of pipe expansion, in order to bring the mating surfaces of the two pipes into a suitable position for the subsequent joining, which is created by means of plastic instability and simultaneous pressure flanging. Experimental tests were carried out with the tools designed to create most suitable joints. The length of the plastically formed pipe sections involved in the joint, the angle of the sharpened pipe ends, and the thickness of the formed joints were analyzed. One of the main goals of this study is to determine the proper joining parameters, such as tool distance or edge tapering for further investigations. As per the test results, it can be stated that the technology is suitable for joining aluminum tubes in a cost-effective way, and based on the promising strength results, further investigations will be conducted.}, year = {2023}, eissn = {1587-379X}, pages = {1-7} } @article{MTMT:34155427, title = {Optimization of Cutting Parameters for Hard Boring of AISI 4340 Steel Using Signal-to-Noise Ratio, Grey Relation Analysis and Analysis of Variance}, url = {https://m2.mtmt.hu/api/publication/34155427}, author = {Gunaraj, Lawrance and Paul, Sam and Mohammed, Jazeel and Sudhagar, Edwin and Thankachan, Titus}, doi = {10.3311/PPme.21729}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {ONLINE FIRST}, unique-id = {34155427}, issn = {0324-6051}, abstract = {Tool vibration in the boring process is the main concern because of the tool overhanging which leads to high tool wear, cutting force and cutting temperature. Interaction between machine dynamics and the metal cutting operation tool also results in tool vibration. The optimized cutting parameters will able to decrease tool vibration and in turn, increase the productivity in the manufacturing sector. In this study, statistical mathematical approaches to develop models for determining the impact of individual cutting parameters on cutting temperature, tool wear, cutting force, and tool vibration when hard boring AISI 4340 steels. During hard boring of AISI 4340 steel, the current investigation consisted of 27 run trials with three varying levels of cutting velocity, feed rate, and depth of cut and each of these variables was tested at three different levels. This work intends to simultaneous optimize statistical analysis such as Signal-to-Noise (S/N) ratio, Analysis of Variance (ANOVA) and Grey Relational Analysis (GRA). ANOVA and S/N ratio is used to identify the important cutting parameters on the single response optimization and GRA is used to optimize the multi-response optimization technique on cutting parameters. The results shows that both single and multi-response optimization technique shows the same optimized cutting parameter.}, year = {2023}, eissn = {1587-379X} } @article{MTMT:34425236, title = {Investigating Particle Paths in Intracranial Aneurysms: A Parametric Study}, url = {https://m2.mtmt.hu/api/publication/34425236}, author = {Gyürki, Dániel László and Paál, György}, doi = {10.3311/PPme.23482}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {67}, unique-id = {34425236}, issn = {0324-6051}, abstract = {A large part of computational fluid dynamics (CFD) studies in hemodynamics concentrates on the berry-like bulgings on cerebral vessel walls, called intracranial aneurysms (IA). One technique is the calculation of particle paths, which can help understand important physiological processes like thrombus formation or drug propagation. The problem is that the particle paths can display chaotic nature even in simple flows, thus, investigating the effects of parameters on the particle paths is essential. The method used in this study consists of four steps. The first step is to voxelize the observed domain into a uniform voxel grid, the second step is to simulate the velocity flow field using the lattice-Boltzmann method, then to calculate one million particle paths using a fourth-order RungeKutta integrator. Lastly, the final step is the calculation of the relative perimeter, relative area and their ratio (P/A ratio) for each outlet when the particle release plane is colored according to the outlets the particles took. Five patient-specific cases were investigated. After a voxel size and integrator time step dependence study, the effect of the presence of the aneurysm sack and the particle release time within the heart cycle were assessed. Based on five geometries, the presence of the aneurysm sac increases the P/A ratio (which is a direct link to the chaotic nature of the particle paths), and when the particles are released near the peak and the decelerating phase of the heart cycle, the P/A ratio also significantly increases.}, keywords = {MODELS; FLOW; velocity; INSTABILITIES; Hemodynamics; residence time; INITIATION; WALL SHEAR-STRESS; Aneurysm; LATTICE-BOLTZMANN; particle path; lattice-Boltzmann simulation}, year = {2023}, eissn = {1587-379X}, pages = {350-360}, orcid-numbers = {Paál, György/0000-0003-1426-2215} } @article{MTMT:34399907, title = {Overall Equipment Effectiveness Prediction with Multiple Linear Regression for Semi-automatic Automotive Assembly Lines}, url = {https://m2.mtmt.hu/api/publication/34399907}, author = {Dobra, Péter and Jósvai, János}, doi = {10.3311/PPme.22302}, journal-iso = {PERIOD POLYTECH MECH ENG}, journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING}, volume = {67}, unique-id = {34399907}, issn = {0324-6051}, abstract = {In the field of industry, especially in the production areas, it is particularly important that the monitoring of assembly efficiency takes place in real-time mode, and that the related data-based estimation also works quickly and reliably. The Manufacturing Execution System (MES), Enterprise Resource Planning (ERP) and Customer Relationship Management (CRM) systems used by companies provide excellent support in data recording, processes, and storing. For Overall Equipment Effectiveness (OEE) data showing the efficiency of assembly lines, there is a regular need to determine expected values. This paper focuses on OEE values prediction with Multiple Linear Regression (MLR) as supervised machine learning. Many factors affecting OEE (e.g., downtimes, cycle time) are examined and analyzed in order to make a more accurate estimation. Based on real industrial data, we used four different methods to perform prediction with various machine learning algorithms, these were the cumulative, fix rolling horizon, optimal rolling horizon and combined techniques. Each method is evaluated based on similar mathematical formulas.}, year = {2023}, eissn = {1587-379X}, pages = {270-275} }