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The research is dedicated to determine one of the most important mechanical properties which is the Young's modulus. Its value is crucial for clearly explaining and understanding the results of any mechanical loading experiment. Three cylindrical samples of 15 mm height and 7.5 mm diameter were designed using SpaceClaim application in the ANSYS Software and then 3D printed using Direct Metal Laser Sintering via EOS M 290 3D printer. The specimens were then tested under compression in order to determine the value of the Young's modulus for titanium alloy of grade 23 (Ti, Al, V, O, N, C, H, Fe, Y). The finite element method was executed using ANSYS mechanical to run a comparison between laboratory results with nominal results of the Young's modulus. Young's modulus value is affected by the 3D printing accuracy and quality, the material's quality as well; however, the deviation is within 10%.

The deviation between the designed lattice structures and the 3D-printed ones has been studied in this research. Three types of lattice structures were designed using the SpaceClaim application in the ANSYS software and then fabricated using Direct Metal Laser Sintering (DMLS) via EOS M 290 3D printer. Considering the orthopedic application, Ti6Al4V alloy of grade 23 was selected as a material for all samples of the structures. A thorough comparison was done on the volume, mass, and porosity to effectively map the possible deviations between the designed and the printed version. The shape accuracy of the 3D printing process was discussed during the study. As the complexity of the shape of the unit cell increases, the accuracy of the printing process becomes lower. Dimensional accuracy in the XY plane is higher than accuracy in the Z plane. Simple unit cell shape was proven to be more accurate in the 3D printing process.

In rubber bumper design one of the most important technical properties of the product is the force-displacement curve under a compression load, which is a highly nonlinear behavior because of the large deformation, the rubber material and the contacts. Finite element analysis is a good way to evaluate the working characteristics of the rubber part. Fulfillment of customer needs requires a general iterative design method where the objective can be reached with the modification of the product shape. The determination of the optimum requires numerous iterations of finite element analysis which is computationally expensive. With the integration of the Response Surface Method (RSM) into the design process of a two-variable shape optimization task, the optimal design can be achieved more efficiently. Four different Design of Experiments (DOE) methods were used to intelligently chose design points. As a metamodeling technique, Genetic Aggregation was selected to predict the relation between the sampled geometric variables and the nonlinear objective function value. The Nonlinear Programming by Quadratic Lagrangian (NLPQL) and the Mixed-Integer Sequential Quadratic Programming (MISQP) algorithms with different settings were tested to find the optimum of the response surface. As a result, the most accurate and efficient DOE method and optimization algorithm were determined. The introduced Response Surface Method-based optimization is proved to be suitable to determine the shape of the rubber jounce bumper, which meets the technical requirements.

The development of medical implants is an ongoing process pursued by many studies in the biomedical field. The focus is on enhancing the structure of the implants to improve their biomechanical properties, thus reducing the imperfections for the patient and increasing the lifespan of the prosthesis. The purpose of this study was to investigate the effects of different lattice structures under laboratory conditions and in a numerical manner to choose the best unit cell design, able to generate a structure as close to that of human bone as possible. Four types of unit cell were designed using the ANSYS software and investigated through comparison between the results of laboratory compression tests and those of the finite element simulation. Three samples of each unit cell type were 3D printed, using direct metal laser sintering technology, and tested according to the ISO standards. Ti6Al4V was selected as the material for the samples. Stress-strain characteristics were determined, and the effective Young's modulus was calculated. Detailed comparative analysis was conducted between the laboratory and the numerical results. The average Young's modulus values were 11 GPa, 9 GPa, and 8 GPa for the

Over the recent years metallic foams have become a popular material due to their unique characteristics like low density coupled with beneficial mechanical properties such as good energy absorption, heat resistance, flame resistance, etc. However, their production processes (foaming) is highly stochastic which results in an inhomogeneous foam structure. Hybrid aluminum foam with closed-cell has been manufactured using direct foaming method coupled with the Taguchi Design of Experiments (DOE). Image analysis has been carried out to determine the average porous area and pore size. The influence of the production parameters (amount of foaming agent added, mixing speed and temperature) on the pore size and the porous area has been analyzed using the statistical Taguchi technique. From the experiments it was seen that the most important control factor for both the pore size and the porous area is the amount of the foaming agent added, followed by temperature and stirring speed. Furthermore, the statistical significance of these manufacturing parameters on the response was also investigated by performing analysis of variance (ANOVA) statistical method.

Nowadays, vehicles with alternative drives are playing an increasingly important role in road transport. Among the various types of alternative-drives, the most widespread ones are hybrid and electric ones, thanks for the rapid development of modern batteries, and hybrid and electrical systems. The above fact establishes the importance of research on various types of electric motors. The Faculty of Engineering of the University of Debrecen has more than a decade of experience in developing prototype race cars with pneumatic and electric drive. For the more effective and conscious development and racing a simulation program has been developed in MATLAB/Simulink environment for the computation of the dynamic functions of a vehicle moving in a linear path. The program is characterized by a modular structure, so the different structural units (vehicle body, front and rear wheels, power train, motor) are modelled and simulated separately. In this study we present models and simulation programs for different electric motor types (series-wound DC and brushless DC motors) in MATLAB/Simulink and apply them in our vehicle dynamics simulation program. From the simulation results the performance of a vehicle – driven by an electric motor – can be predicted in a race situation, consequently the most suitable motor with the optimal characteristics can be selected to it.

The important properties of metallic foams such as good energy absorption, recyclability, noise absorption, etc. have put them at the forefront of technological development over recent years, especially for fields where the weight is a major concern. The production however, is a highly stochastic process which leads to their inhomogeneous nature. In this paper closed-cell aluminum foam specimens have been produced by direct foaming technique and investigated mechanically, following the principles of Taguchi Design of Experiments (DOE). The important compressive properties of the produced specimens such as the structural stiffness, yield strength, plateau stress and energy absorption have been measured through uniaxial compression tests and the effect of the manufacturing parameters (the temperature, the mixing speed and the amount of foaming agent added) on the energy absorption capacity of the foam is analyzed. From experiments, it was observed that the temperature is the most dominant control factor for the energy absorption capability of the foam followed by the foaming content and the mixing speed. ANOVA statistical analysis was also performed to determine the statistical significance of these parameters on the response.

In our previous publication a model for series wound direct current (SWDC) motors was described and a simulation program was presented which is based on the above model and was developed in MATLAB environment. In the publication mentioned above, the measurement process of the parameters (bearing resistance torque, electric resistances, dynamic inductances) of the SWDC motor was also described. From the parameters the program calculates the current intensity, rpm and torque of the motor as a function of time. The recent publication is about the realization of the above program applying the Control Design and Simulation Module of NI LabVIEW. This module enables the adjustment of input parameters (e.g. supply voltage) during the running of the program, thus the realization of real time driving simulation. In addition, among others, it can be applied with data acquisition, GPIB, CAN, and FPGA (field-programmable gate array) hardware platforms of National Instruments.

Fiber-reinforced hybrid composites are the most commonly used dry-friction materials in the automotive industry. On the other hand, the great variety of components utilized these days in such material systems often requires identification investigations for a complex characterization. The development history of clutch materials was reviewed, highlighting and understanding the milestones and efforts leading to the creation of these materials. Investigations were performed to determine mechanical stiffness matrix parameters and thermal properties of a woven fiber yarn (glass fiber with aromatic polyamide, copper, and poly-acrylic-nitrile (PAN) reinforced friction material, revealing and solving challenges faced during identification efforts. This study grants an effective reference and a novel guidance for material identification methods for similar complex materials, and the results provide input parameters for thermomechanical simulation contact model development, which will cover friction material lifetime effects on dry clutch tribology in a future study.

The present paper concentrates on the toughness and the degree of crystallinity of the magnesium-catalyzed polyamide 6 rods cast in different diametres, which are commonly used for gear manufacturing. Its toughness cannot be regarded as a constant feature due to the casting technology. The mechanical properties of the semi-finished products are sensitive to the manufactured dimension, e.g., cast diameter, which are investigated by the Charpy impact test and tensile impact test. It is generally accepted that the impact strength and tensile-impact strength correlate with the degree of crystallinity beside many other material&rsquo, s feature. Crystallinity is evaluated by Differential Scanning Calorimetry. The aim of this study is to determine the relationship between toughness and crystallinity of the magnesium-catalyzed cast PA6 rods with different diameters. For the research cast rods between 40 and 300 mm diameter were selected in seven-dimensional steps. Based on the results, it was found that the toughness depends strongly on the diameter size. Furthermore, it is proved that the crystallinity explains 62.3% of the variation of the Charpy&rsquo, s impact strengths, while the tensile impact method was not suitable to detect the difference between the test samples.

The geometrical modelling of metal foams remains one of the greatest challenges facing researchers in the field. In this paper the analysis of the inner structure of closed-cell aluminium foam - an essential part of the construction of an idealized foam model - is presented. With the application of special purpose software the properties of the foam cells can be mapped precisely and the results applied to the development of idealized foam geometry constructed in CAD applications.

Fault diagnosis of bearings is essential in manufacturing to increase quality. Traditionally, fault diagnosis of tapered roller element bearings is performed by signal processing methods, which handle the nonstationary behaviour of the signal. The wavelet transform is an efficient tool for analysing the vibration signal of the bearings because it can detect the sudden changes and transient impulses in the signal caused by faults in the bearing elements. In this article, manufacturing faults on the outer ring of tapered roller bearings due to the grinding process in manufacturing are investigated. Nine different real values wavelets (Symlet-2, Symlet-5, Symlet-8, db02, db06, db10, db14, Meyer, and Morlet) are compared according to the Energy-to-Shannon-Entropy ratio criteria, and which is efficient for detecting the manufacturing faults is determined. Finally, experiments are carried out on a test rig for determining the geometrical size of the manufacturing faults with all wavelets directly from the vibration signature the result of db02, Symlet-5, and Morlet wavelets are presented. When modelling the bearing structure as an under-damped second-order mass-spring-damper mechanical system, its unit impulse response function is compared to the wavelets on the basis of their Energy-to-Shannon-Entropy ratio to determine the fault size from the vibration signal. The proposed technique has been successfully implemented for measuring defect widths. The maximum deviation in result has been found to be 4.12 % for the defect width which was verified with image analysis methods using an optical microscope and contact measurement. Odkrivanje napak v izdelavi je ključnega pomena za izboljšanje kakovosti proizvodnje ležajev. Namen članka je analiza možnosti odkrivanja napak v izdelavi koničnih kotalnih ležajev iz signala vibracij ter ugotavljanje geometrijske velikosti napak na zunanjem obroču. Tradicionalne metode, kot je Fourierjeva transformacija, zaradi posebne narave signalov niso dovolj uspešne pri zaznavanju prehodnih impulzov. Konični kotalni ležaji so le redko predmet znanstvenih člankov, čeprav predstavljajo pomemben del avtomobilskih menjalnikov in sistemov prenosa moči. Večina znanstvenih člankov, ki se ukvarjajo z obrabo, se kljub pomenu te problematike ne posveča težavam pri izdelavi. V članku je zato predstavljena nova rešitev, ki bi jo bilo mogoče učinkovito uporabiti v industriji.

The development of an efficient procedure for 3d modeling and finite element simulation of metal foams is one of the greatest challenges for engineer researchers nowadays. Creating 3d CAD model is alone a demanding engineering task due to its extremely complex geometry, and the proper finite element analysis process is still in the center of the research. The increasingly widespread application of the metal foams, e.g. in vehicle and medical industry, requires this knowledge in the design phase. A closed-cell metal foam is studied using different analyzing methods where the aim is to collect information about the composition and geometry (structure) that is satisfactory for the later research. Using statistical methods microscopic, X-ray and surface analyzing studies on the specimens produced according to the concerning standard are evaluated. The main goal of this part of the project is to obtain structural information and to determine the homogeneity or the in-homogeneity property of the metal foam specimens taken from different locations.

In rubber products design finite element analysis is a widely used technique. In many cases, the pre-defined operating conditions can be achieved by changing the geometric dimensions of the product which is the well-known iterative design method. Using more than one design parameter the number of possible combinations will increase significantly. The application of Support Vector Machine (SVM) can handle the large number of data in a special way and helps to find the optimal design parameters. In this paper an optimization process of a rubber jounce is presented using nonlinear finite element analysis and SVM.

The rubber bumpers built into the air-spring structures of buses perform a number of critical tasks. Consequently, designing their shape requires considerable effort. This paper presents a novel solution for determining the required characteristics of axi-symmetric rubber parts, which can efficiently be used in practice. The procedure is based on the finite element method (FEM) and the support vector regression (SVR) model. A finite element code developed by the authors and based on a three-field functional is used for the rapid and appropriately accurate calculation of the characteristics of rubber bumpers. A rubber shape is evaluated via the work difference and the area between the desired and the actual load-displacement curves. The objective of shape optimization is to find the geometry where the work difference is under a specified limit. The tool of optimization is the SVR method, which provides the regression function for the work difference. The minimization process of the work-difference function leads to the optimum design parameters. The efficiency of the method is verified by numerical examples. Gumijasti blažilniki, vgrajeni v sisteme zračnega vzmetenja avtobusov, opravljajo vrsto pomembnih nalog, konstruiranje gumijastih blažilnikov pa je zato precej zahtevno. V članku je predstavljena nova, praktično uporabna rešitev za zagotavljanje zahtevane karakteristike gumijastih osnosimetričnih blažilnikov. Prava karakteristika podajanja pod obremenitvijo je osnovna zahteva pri snovanju gumijastih blažilnikov. Avtomobilska industrija mehkejšo ali tršo izvedbo gumijastih blažilnikov običajno zagotavlja s spremembo sestave gume. Cilj optimizacije je doseganje zahtevane karakteristike z geometrijsko obliko gumijastega blažilnika ob nespremenjenih lastnostih materiala. Namen raziskave je določanje vedenja gumijastih blažilnikov pri različnih delovnih pogojih. Gumijasti blažilniki se ne upravljajo aktivno, zato je zahtevano karakteristiko mogoče doseči z optimizacijo oblike.

This paper presents a novel solution for shape optimization of compressed rubber parts. The procedure is based on the finite element method (FEM). A special purpose FEM code written in FORTRAN has been developed for the analysis of nearly incompressible axi-symmetric rubber parts. Numerical stability of the code and sensitivity analysis of the FEM input parameters are investigated. The aim of the parameter optimization is to reduce the time consuming FEM computations for the optimization process. The objective of the optimization is to find the optimal shape of the investigated rubber parts with a specified load-displacement curve. A regression model is used to determine the connection between the input and output data calculated by the FEM.

In this paper a solution of a contact problem for large displacements and deformations are analyzed where a rubber bumper applied in air–spring. The nonlinear load-displacement curve is determined. A FEM code written in FORTRAN has been developed for the analysis of nearly incompressible axially symmetric rubber parts. The Hu Washizu type variational principle is formulated for the Mooney-Rivlin material model. Stability and sensitivity analyses are also investigated.

This paper deals with the main principles of shape optimization of elastomers. The aim of the research is how to find the right optimizing solutions which can handle rubber components used in vehicle industry. Further on the chosen solution algorithms will be built in the developed finite element code.

In rubber product design finite element analysis is widely used. The aim of this research is to choose the appropriate material models and to determine the related material parameters for finite element analysis of a rubber jounce. Rubber products can suffer from large deformation upon working conditions while behaving as a non-linearly elastic, isotropic and incompressible material. Hyperelastic material models accurately describe the observed material behaviour. Uniaxial compression test of rubber specimen has been performed to determine the stress-strain curve. Using test data and ANSYS for curve fitting process, the material constants for Mooney-Rivlin and Yeoh model have been established. Finite element analysis of the compression test has been made to validate the specified material constants. It can be stated that three term Yeoh model showed better agreement with the test data than the one term formula. Two term Mooney-Rivlin model showed good match with the measurement data, thereby it is also recommended for the future investigations of rubber jounce.

Non-linear FEM calculations are indispensable when important technical information like operating performance of a rubber component is desired. For example rubber bumpers built into air-spring structures may undergo large deformations under load, which in itself shows non-linear behavior. The changing contact range between the parts and the incompressibility of the rubber increases this non-linear behavior further. The material characterization of an elastomeric component is also a demanding engineering task. The shape optimization problem of rubber parts led to the study of FEM based calculation processes. This type of problems was posed and investigated by several authors. In this paper the time demand of certain calculation methods are studied and the possibilities of time reduction is presented., {"references":["J. J. Kim, H. Y. Kim, \"Shape design of an engine mount by a method of\nparameter optimization,\" Computers and Structures, vol. 65, no. 5, pp.\n725-731, 1997.","K. K. Choi, W. Duan, \"Design sensitivity analysis and shape\noptimization of structural components with hyperelastic material,\"\nComputer Methods in Applied Mechanics and Engineering, vol. 187, pp.\n219-243, 2000.","J. S. Lee, S. C. Kim, \"Optimal design of engine mount rubber\nconsidering stiffness and fatigue strength,\" Journal of Automobile\nEngineering, vol. 221, no. 7, pp. 823-835, 2007.","V. T. Vu, \"Minimum weight design for toroidal pressure vessels using\ndifferential evolution and particle swarm optimization,\" Structural and\nMultidisciplinary Optimization, vol. 42, no. 3, pp. 351-359, 2010.","T. Mankovits, I. Kocsis, T. Portik, T. Szabó, I. Páczelt, \"Shape Design\nof Rubber Part Using FEM,\" International Review of Applied Sciences\nand Engineering, vol. 4, no. 2, pp. 85-94, 2013.","N. Kaya, \"Shape optimization of rubber bushing using differential\nevolution algorithm,\" The Scientific World Journal, ID 379196, pp. 1-9,\n2014.","K. Shintani, H. Azegami, \"Shape optimization of rubber bushing,\" 11th\nWorld Congress on Computational Mechanics, 20-25 July, Barcelona,\nSpain, 2014.","T. Mankovits, T. Szabó, I. Kocsis, I. Páczelt, \"Optimization of the Shape\nof Axi-Symmetric Rubber Bumpers,\" Strojniski vestnik-Journal of\nMechanical Engineering, vol. 60, no. 1, pp. 61-71, 2014.","ISO 7743 \"Rubber, vulcanized or thermoplastic – Determination of\ncompression stress-strain properties\", 2008."]}

Non-linear FEM calculations are indispensable when important technical information like operating performance of a rubber component is desired. Rubber bumpers built into air-spring structures may undergo large deformations under load, which in itself shows non-linear behavior. The changing contact range between the parts and the incompressibility of the rubber increases this non-linear behavior further. The material characterization of an elastomeric component is also a demanding engineering task. In this paper a comprehensive investigation is introduced including laboratory measurements, mesh density analysis and complex finite element simulations to obtain the load-displacement curve of the chosen rubber bumper. Contact and friction effects are also taken into consideration. The aim of this research is to elaborate a FEM model which is accurate and competitive for a future shape optimization task., {"references":["T. Mankovits, T. Szabó, I. Kocsis, I. Páczelt, \"Optimization of the Shape of Axi-Symmetric Rubber Bumpers,\" Strojniski vestnik-Journal of Mechanical Engineering, vol. 60, no. 1, pp. 61-71, 2014.","T. Mankovits, T. Szabó, \"Finite Element Analysis of Rubber Bumper Used in Air-Springs,\" Procedia Engineering, vol. 48, pp. 388-395, 2012.","T. Mankovits, I. Kocsis, T. Portik, T. Szabó, I. Páczelt, \"Shape Design of Rubber Part Using FEM,\" International Review of Applied Sciences and Engineering, vol. 4, no. 2, 85-94, 2013.","R.K. Luo, W.X. Wu, \"Fatigue Failure Analysis of Antivibration Rubber Spring,\" Engineering Failure Analysis, vol. 13, no. 1, pp. 110-116, 2006.","Q. Li, J. Zhao, B. Zhao, \"Fatigue Life Prediction of a Rubber Mount Based on Test of Material Properties and Finite Element Analysis,\" Engineering Failure Analysis, vol. 16, no. 7, pp. 2304-2310, 2009.","S. Oman, M. Fajdiga, M. Nagode, \"Estimation of Air-Spring Life Based on Accelerated Experiments,\" Materials and Design, vol. 31, no. 8, pp. 3859-3868, 2010.","S. Oman, M. Nagode, \"On the Influence of Cord Angle on Air-Spring Fatigue Life,\" Engineering Failure Analysis, vol. 27, pp. 61-73, 2013.","L.R. Wang, J.C. Wang, I. Hagiwara, \"An Integrated Characteristic Simulation Method for Hydraulically Damped Rubber Mount of Vehicle Engines,\" Journal of Sound and Vibration, vol. 286, no. 4-5, pp. 673-696, 2005.","ISO 7743 \"Rubber, vulcanized or thermoplastic – Determination of compression stress-strain properties\", 2008."]}