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The summary of recent research towards development of a tool for detailed microstructure modelling is presented within the paper. The main focus is put on micro scale behaviour, where advantages of digital material representation can be taken into account. Digital Material Representation allows modelling of microstructures along with features such as crystallographic orientation, grain boundaries or phase boundaries represented in an explicit manner. Incorporation of these digital microstructures into the numerical simulation methods provides the possibility to improve the quality of numerical results. The developed method can be used to design specifically dedicated microstructures, which meet very strict requirements. The clear motivation and importance of the work is presented in the first part of the paper followed by a short description of the developed approaches for creation of the digital microstructures. Two approaches are considered that provide an exact and statistical representation of the real microstructure. The main focus is put on the application of image processing and cellular automata techniques. Afterwards, obtained digital microstructures are used as input data for the finite element analysis of the micro scale compression test. Examples of applications during multiscale simulation are also presented in the paper. [ABSTRACT FROM AUTHOR]

Numerical methods for thixoforming modelling are shortly reviewed in the paper. Present applications, especially for thixotropy phenomena modelling, are presented. Advantages and disadvantages of methods based on solid mechanics or computational fluid dynamics are pointed out. Internal Variable Convection (IVC) method is introduced as an alternative for classical Lagrangian or Eulerian methods. Numerical simulations of T-shape mould filling, based on the data taken from literature, are shown. Presented results confirm possibilities of thixoforming processes modelling with Internal Variable Convection method. However, some deficiencies of the present solution are pointed out in the paper as well. It concerns mainly material front tracking methods and treatment of boundary layer. Some ways to resolve existing constraints, as well as plans for future are presented. [ABSTRACT FROM AUTHOR]

Because of the properties of the material (concrete), computer simulations in the field of reinforced concrete structures are pose a challenge. As opposed to steel, concrete when subjected to compression exhibits nonlinearity right from the start. Moreover, it much quicker undergoes degradation under tension. All this poses difficulties for numerical analyses. Parameters needed to correctly model concrete under compound stress are described in this paper. The parameters are illustrated using the Concrete Damaged Plasticity model included in the ABAQUS software. [ABSTRACT FROM AUTHOR]

Car-to-pedestrian front impacts have been well described in the papers. However, there is still insufficient data measuring the performance of new type of Frontal Protection Systems (FPS) fitted on Sport Utility Vehicles (SUVs). Therefore, the aim of the studies was to validate the method of the FPS design, complying with the European Commission Regulations. The complete numerical model of the vehicle front with FPS was created and then subjected to a precise pedestrian impactor subtest. The physical experiment results proved good conformity with the outcomes from numerical simulations. Hence, the design of the presented FPS design was a base for legal process such as European Union homologation. [ABSTRACT FROM AUTHOR]

This paper presents the determination of virtual micro-forming limit diagrams from two types of numerical simulations based on the finite element method: one with modelling of the full tool for micro-deep drawing and a thin blank with geometric imperfections, based on a defined roughness; and a second called "reduced simulation" where different deformation paths were simulated with appropriate boundary conditions by introducing the same type of geometric imperfections on aluminium 1050A (99.5%). A new test for detecting the onset of necking, called the "change of slope" criterion has been defined. Several methods based on histograms to represent the distributions of major and minor strains, have been used to determine the strain at the onset of necking. The numerical micro-forming limit diagrams (MFLD) were then compared to one obtained experimentally. [ABSTRACT FROM AUTHOR]

One of the limitations related with joining several micro parts is the temperature generated during joining methods based on material heating. Temperature concentration could be a reason of severe difficulties with micro-manufacturing applications. It seems that modern mechanical joining technologies could significantly facilitate micro-parts fastening, since there is lack of temperature development during the process. Recently mechanical joining methods undergo considerable development and become more and more competitive in the industry. Among them, the self-piercing -- SPR -- technology is one of the most advanced and flexible. Initially, the automotive industry was a first application of the SPR, and then have been started to be use in other industry areas. In the paper, possibility of micro-rivet production by micro-forming with heat treatment elimination has been researched by means of FEM analysis. Required rivet strength is achieved by designed cold forming process and followed by effect of material hardening. Various stress distributions in the rivets are taken into account during numerical simulation to prove their influence on joining quality. Commercial FEM software MSC.Marc is used for numerical simulations. [ABSTRACT FROM AUTHOR]

Hydroforming is a cost effective way of shaping various metals and alloys into lightweight, structurally stiff and strong pieces. The largest applications of hydroforming can be found in the automotive and aerospace industries. Among them, exhaust system components such as T-shapes or X-shapes connectors have been often manufactured by tube hydroforming. Typical tube hydroforming operation is made by a controlled application of internal pressure and axial feeding of tube material into deformation zone. The loading path of internal pressure versus axial feeding is the most important. It can be found by means of FEM simulation of the process to limit costs of experiments. However, the appropriate numerical model requires experimental data on tube material properties. Some simplifications to use sheet metal properties instead of tube properties have not been reliable. Especially cold worked tubes with small diameters require special methods to determine material properties in axial and circumferential directions. Such methods have been presented in the paper including some remarks on specimens' preparation, experimental set-up and image processing for getting strain values. [ABSTRACT FROM AUTHOR]

The cycle of investigations on applying tailor welded blanks (TWB) for sheet forming processes was conducted at Department of Materials Technology of the Silesian University of Technology and as The European Research Project Acronym SIM-TWB. The model of tailor welded blank (TWB model) have been worked out and great number of FEM simulations of stamping process of different geometry drawpieces using TWB were conducted. The paper presents the practical verification of simulation results of stamping process of car body draw-pieces: B-pillar and reinforcement of floor of boot, applying TWB for stamping. Stampack -- a commercial program for FEM simulation was applied, as well as worked out 5-zones TWB model have been used. The practical verification showed the good agreement of results of simulation and practical experiments of stamping processes of both chosen drawpieces. Hence worked out TWB model is proper and recommend to simulation of TWB forming processes. [ABSTRACT FROM AUTHOR]

Belt conveyors are commonly used in-factory transportation devices built of sections of belt (e.g., a fabric-rubber belt) bonded into a continuous loop. Conveyor belt joints are exposed to substantial dynamic loads during the long time of their operation. Taking into account the fact that ensuring a high durability of conveyor belt joints is tantamount to guaranteeing their reliable operation and that the results of research conducted so far fail to provide unambiguous solutions to a number of problems that emerge in this case, it is advisable that advanced studies using computer techniques should be conducted within this area. Of particular help in the search for new structures and optimum methods for joining conveyor belt sections is finite element analysis, which, however, entails a number of problems. This paper describes the circumstances of occurrence of these problems and potential solutions to them. One important problem in FEM modeling is appropriate definition of the models of the analyzed materials. In the case of conveyor belt adhesive-bonded joints composed of rubber and a gum rubber adhesive, the analyses found in the literature, as a general rule, assume the hyperelastic material model based on the Mooney-Rivlin law, which, however, is a fairly arbitrary choice made without verification against actual strength test data. Rubber is a unique material, capable of very large deformations, by virtue of which it is counted among hyperelastic materials. Such materials require appropriate constitutive models and a reliable choice thereof in each particular case. Adequately precise modeling of the behavior of rubber materials still remains an open question. However, access to strength test data makes it possible to cheek experimentally which of the available theoretical models best reproduce the behavior of the modeled material. For that purpose, the available hyperelastic material models were tested separately for each constituent rubber material of the analyzed conveyor belt adhesive joint. The models were assessed with regard to the degree of their conformity with experimental data by analyzing the behavior of the hyperetastic material in a given case based on the constructed reaction curves using selected strain energy potentials for the available test data. [ABSTRACT FROM AUTHOR]

In this paper, the tensile behaviour of a commercially pure titanium is studied using a full-field strain measurement. A fine analysis of the measured strain fields is carried out in order to determine the intrinsic behaviour of the material. An elastic-plastic model taking material anisotropy into account is proposed. On the basis of experimental results, the parameters of this model are identified then introduced into a FEM code in order to simulate the behaviour of titanium, To assess the performance of the approach, the numerical results are finally analysed and compared with measurements coming from image processing. A quite satisfactory agreement between simulation and experiment is obtained. [ABSTRACT FROM AUTHOR]

Numerical modeling of the SPR process can be very efficient way for optimization of the strength of a joint obtained by this method. During numerical simulation one of the important problems is to define precisely the moment of upper layer separation leading to rivet penetration of lower layer(s). In the paper, a review of selected material separation criteria available in commercial MSC software applied for the SPR process simulation is presented. [ABSTRACT FROM AUTHOR]

Within a national research project on aircraft dynamic loads and resultant structural response the task was given to investigate aircraft emergency landings on water, generally called "ditching". The work was initiated and funded by Airbus Industries. As controlled experiments for such events are costly and difficult to extrapolate to full-scale, the study at HSVA was completely based on computer simulations. The commercial RANS solver "Comet" was used to determine the path of the aircraft fuselage from initial conditions in air given at t = 0. After being released in air, the aircraft fuselage was free to react on the forces and moments developing at the free surface. In order to simplify the approach the hydrodynamic forces were derived in all details by the RANS simulation while the aerodynamic forces and moments were approximated. Simultaneously, the simulations were performed at the TUHH using the program "Ditch", based on an extension of the "momentum method" developed by von Karman and Wagner. The results are presented in this paper for generic fuselage shapes called A-, D- and J-Body in terms of motion histories and section forces. [ABSTRACT FROM AUTHOR]

Purpose of this paper is to analyse correlation between CFD calculation and experiments on axisymmetric body with working propeller. Model tests were conducted in 1981-1986 in the cavitation tunnels of Ship Propeller Department of the Institute of Fluid Flow Machinery of the Polish Academy of Sciences and in Ship Hydromechanics Division Ship Design and Research Centre in Gdańsk [1-6]. CFD calculations were made in 2007 in Ship Hydromechanics Division Ship Design and Research Centre in Gdańsk. [ABSTRACT FROM AUTHOR]