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This paper deals with finite element analysis of fundamental deformation of robot soft finger. The aim of this paper is to develop a simple contact static model of cylindrical soft flexible finger for effective power grasping. In this paper, the geometrical relation connecting different contact parameter, for example, distortion, flexible contact width, and contact angle of developed soft finger are derived. Formula for total force on fundamental deformation has been analyzed using simple mathematics. Selection of appropriate soft elastic material required for modelling of flexible finger is based on fundamental deformation and change in contact width with respect to applied normal load ranges from 0 to 100 N. Experiment is performed for 3 different nonlinear hyper soft elastic materials: Neoprene W, Viton E-60C and Silicone R401/70. Furthermore, deformation of cylindrical finger was determined by performing compression testing for each finger with load step 10 N. Contact width was determined by measuring vivid print observed above the recording paper. Additionally, coefficient of friction (COF) flanked by soft finger and target was measured by performing inclined test. Further, experimental result was successfully validated with finite element simulation performed on ANSYS software. [ABSTRACT FROM AUTHOR]

The equations of the combined model of phase and structural deformation of shape memory alloys (SMA) express the increments of deformations in terms of the increments of stresses, martensite volume part parameter and temperature, stresses themselves, deformations, and the temperature. However, to solve the stability problems of long-or thin-walled elements from SMA, as well as to formulate the tangent stiffness matrix of the finite element method for SMA, it is necessary to have an explicit expression of stress increments in terms of stresses, deformations, strain increments, temperature increments, and temperature. The paper presents an analytical method for obtaining such inverting. [ABSTRACT FROM AUTHOR]

Numerous empirical and numerical studies have been carried out on the mechanical characterization of ductile materials. The application of digital image correlation (DIC) equipped with three-dimensional measurement analysis was used to examine the mechanical characteristics of aluminum alloy (AL 7075). Then, the DIC outcome with finite element simulation results will be compared with the experimental results to measure the performance of the DIC. A tensile specimen of AL 7075 is tested under constant loading with a 2 mm/min displacement rate until fracture. Strain gauge and extensometer are used along with DIC monitoring technique to capture the structural deformation of the specimens. The specimen and test are simulated in ABAQUS software, in which the results are compared with experiment and DIC data, indicating a good correlation between the results. Limited data in the form of average deformation and strain of the experiments are not applicable to the plastic and necking process. In this respect, the 3D DIC results are used to analyze the strain field throughout the test, including specimen necking, and predict fracture location. Moreover, the outcome of DIC and finite element simulation are employed to examine the characteristics of AL 7075 about the large plastic deformation and mechanical behavior. The proposed 3D DIC methodology in providing insight into the characteristic mechanical behavior of ductile materials is highlighted in this paper. [ABSTRACT FROM AUTHOR]

Rollovers are complex road accidents causing a big deal of fatalities. FE model for rollover study will costtoo much time due to its long duration. A new multi-body modeling method is proposed in this paper which can save a lot of time and has high-fidelity meanwhile. Following works were carried out to validate this new method. First, a small van was tested following the FMVSS 208 protocol for the validation of the proposed modeling method. Second, a MADYMO model of this small van was reconstructed. The vehicle body was divided into two main parts, the deformable upper body and the rigid lower body, modeled by different waysbased on an FE model. The specific method of modeling is offered in this paper. Finally, the trajectories of the vehicle from test and simulation were compared and the match was very good. Acceleration of left B pillar was taken into consideration, which turned out fitting the test result well in the time of event. The final deformation status of the vehicle in test and simulation showed similar trend. This validated model provides a reliable way for further research in occupant injuries during rollovers. [ABSTRACT FROM AUTHOR]

Identification of parameters of laser beams is important in all applications of lasers. In this paper, results of numerical verification are presented for identification of parameters of pulsed, high-power laser beam based on displacement fields of the target body. It is considered how laser power as well as spatial and temporal characteristics of the beam may be recovered based on measurements of thermally-caused deformation of thin aluminum plate. Mechanical displacement of the plate surface was calculated using Finite Element Method (FEM), for selected time instants, based on solutions of the unsteady thermal problem obtained with Finite Volume Method (FVM). Sensitivity of measured displacements to changes of recovered laser pulse parameters is discussed. Preliminary results of parameter estimation based solely on measurements of the Z-component of displacement field were compared with results of estimations based on measurements of temperatures. The comparison was made for inverse problems solved using Levenberg-Marquardt method applying synthetic measurement data instead of physical one. It was found that solutions of the inverse problem based on temperatures are better than those based on mechanical analysis. [ABSTRACT FROM AUTHOR]

The paper presents the innovative process with possibility of predict the state of deformation and stresses in a two-stage metal forming process. In the first stage, regular surface roughness with arched outlines are embossed. In the second stage, these inequalities are flat burnished to obtain the required dimensions, roughness of the surface, and state of deformation and stresses in the surface layer of the workpiece. The process are considered as a geometrical and physical non-linear boundary and initial value problem, with unknown boundary conditions in the contact zone. The applications were developed in the Ansys/LS-Dyna system, which makes possible a complex time analysis of the states of displacements, strains and stresses, in the workpiece in the two-stage cold metal forming processes. Application of this method were showed for examples the modelling and the analysis of the regular asperities with arched outlines. In the simulations, the material as well as the geometrical parameters of surface asperities were changed. The simulation results were verified experimentally. [ABSTRACT FROM AUTHOR]

One of the main problems in control is that the overwhelming number of physical quantities cannot be measured directly. Hence, there arise so-called inverse problems on the determination of physical quantities from the results of their manifestations. In the mechanics of a deformable solid there is a problem of obtaining material properties at all stages of deformation and especially at the overcritical stage. In this paper, we formulate and solve the inverse problem of finding the tensile diagram of a material element from the diagram of the dependence of the bending moment on the curvature of a rectangular beam under pure bending. [ABSTRACT FROM AUTHOR]

Computer simulation is widely used in the design and development of technical products. Multiscale nature of deformation and fracture of novel materials requires to use for this purpose not only the conventional finite element method but particle methods at different spatial scales as well. This paper presents a computer code aimed for discrete-continuum simulation of friction based on coupling finite elements (as a continuum method) with movable cellular automata (discrete particle method). Two computer codes based on finite elements and written in different programming languages are used: commercial and in-house. Peculiarities of the application program interfaces of the particle code for coupling with both finite element codes are described and analyzed. It is shown that the code developed takes the advantages of both cases and promises to be very efficient for simulating various contact problems including friction. [ABSTRACT FROM AUTHOR]

In this paper, a fully adaptive 3D numerical methodology based on a tetrahedral element was proposed in order to improve the finite element simulation of any metal forming process. This automatic methodology was implemented in a computational platform which integrates a finite element solver, 3D mesh generation and a field transfer algorithm. The proposed remeshing method was developed in order to solve problems associated with the severe distortion of elements subject to large deformations, to concentrate the elements where the error is large and to coarsen the mesh where the error is small. This leads to a significant reduction in the computation times while maintaining simulation accuracy. In addition, in order to enhance the contact conditions, this method has been coupled with a specific operator to maintain the initial contact between the workpiece nodes and the rigid tool after each remeshing step. In this paper special attention is paid to the data transfer methods and the necessary adaptive remeshing steps are given. Finally, a numerical example is detailed to demonstrate the efficiency of the approach and to compare the results for the different field transfer strategies. [ABSTRACT FROM AUTHOR]

Ring Rolling is an advanced local incremental forming technology to fabricate directly precise seamless ring-shape parts with various dimensions and materials. In this process two different deformations occur in order to reduce the width and the height of a preform hollow ring; as results a diameter expansion is obtained. In order to guarantee a uniform deformation, the preform is forced toward the Driver Roll whose aim is to transmit the rotation to the ring. The ring rotational speed selection is fundamental because the higher is the speed the higher will be the axial symmetry of the deformation process. However, it is important to underline that the rotational speed will affect not only the final ring geometry but also the loads and energy needed to produce it. Despite this importance in industrial environment, usually, a constant value for the Driver Roll angular velocity is set so to result in a decreasing trend law for the ring rotational speed. The main risk due to this approach is not fulfilling the axial symmetric constrain (due to the diameter expansion) and to generate a high localized ring section deformation. In order to improve the knowledge about this topic in the present paper three different ring rotational speed trends (constant, linearly increasing and linearly decreasing) were investigated by FEM approach. Results were compared in terms of geometrical and dimensional analysis, loads and energies required. [ABSTRACT FROM AUTHOR]

This paper concerns the numerical modeling of deformation behavior taking into account the pores shape of porous materials. In the research were used porous sintered 316L stainless steel. These types of materials have wide application, among others, in the automotive, aerospace and medical industries, e.g. for the production of bone substitutes. The production process of sinters causes heterogeneous distribution of pores in different directions. This results in the occurrence of anisotropy in a deformed porous material. The use of X-ray computed microtomography allowed to the mapping of the real shape of pores in mesoscopic scale. Based on the obtained microtomographic images were generated three-dimensional geometrical models of porous mesostructures. The micro-CT device has a limited measurement accuracy, which results in a lack of mapping of small pores and fissures of porous structures. For this reason, in the study used two methods for compensating the influence of the measurement inaccuracies on numerical calculations. Received geometrical models were used for numerical calculation using the finite element method (FEM). Based on the numerical results, was determined the influence of the material inhomogeneity on its mechanical properties are and how the sintering process effects on the anisotropic deformation behavior. [ABSTRACT FROM AUTHOR]

The paper determines the actual stress-strain state of a vertical steel tank RVS-20000's bottom considering the subsoil base inhomogeneity zones of various sizes. Using the ANSYS software a finite element model of the RVS-20000's bottom has been developed. A design scheme proposed in the article takes into account the impact of the out-contour space. Analysis of the test calculation results has shown that the area of maximum stress acting on the vertical steel tank bottom is located along the perimeter of the base subsidence area. There are dependences that characterize tank bottom sags at maximum operating stress occurring in the metalwork of the tank bottom and concentrated on the border of the subsidence area out-contour zone in the paper end. It is found that Russian regulatory documents require harmonization with international standards. [ABSTRACT FROM AUTHOR]

Among forging processes, incremental processes are those where the work piece undergoes several thermal and deformation steps with small increment of deformation. They offer high flexibility in terms of the work piece size since they allow shaping wide range of parts from small to large size. Since thermal treatment is essential to obtain the required shape and quality, this paper presents the thermal modeling of incremental processes. The finite element discretization, spatial and temporal, is exposed. Simulation is performed using commercial software Forge 3. Results show the thermal behavior at the beginning and at the end of the process. [ABSTRACT FROM AUTHOR]

This paper concerns the application of variational methods for the formulation of object motion equations as well as generation heat and its transfer formulated in the updated Lagrange description. These physical phenomena occur in the processing of metals in which there are thermal, plastic viscous and phase deformations. The obtained incremental variation equation of the object's motion and the incremental variation of the heat conduction equation were discretized by the Finite Element Method to obtain discrete systems of equations. These equations are solved by known methods for given boundary and initial conditions. As a result, a column vector of the displacement increment and a column vector of the temperature increment in the object nodes are obtained at each time step. Examples of the use of these methods for the burnishing rolling process with electric current are shown. [ABSTRACT FROM AUTHOR]

B-Pillars are specifically designed to absorb substantial energy with a minimum amount of deformation to limit its intrusion in the passenger compartment during an event of side impact. In this paper, the B-pillar has been developed using composite materials, with the main objective is to improve crashworthiness performance at a lesser weight, as a replacement for steel. The three-point bending test simulations of the composite B-pillar model were modelled, which applied various parameters of materials, number of ply and additional reinforcement. The composite B-pillar design parameter that scored the highest performance to weight ratio in the numerical simulation was then fabricated using vacuum bagging method. Subsequently, the B-pillar was tested under three-point bending experimental work. The force and central displacement results were compared to simulation data and a good agreement was obtained, where B-pillar made of carbon fibre reinforced polymer (CFRP) performed better than glass fibre reinforced polymer (GFRP). The simulation and experimental results indicated errors ranging between 6 and 15%. With the additional reinforcement at the critical area, the energy absorption of CFRP B-pillar was considerably improved by 18%. The weight of the fabricated composite B-pillar was 58% lighter compared to the original steel B-pillar. These results confirmed that the novel composite material holds a high strength, and has lightweight potential to substitute steel as car B-pillar material. [ABSTRACT FROM AUTHOR]

Beam-to-column end-plate bolted connections are usually used as moment-resistant connections in steel framed structures. For this joint type, the deformability is governed by the deformation capacity of the column flange and end-plate under tension and elongation of the bolts. All these elements around the beam tension flange form the tension region of the joint, which can be modeled by means of equivalent T-stubs. In this paper a beam-to-column end-plate bolted connection is substituted with a T-stub of appropriate effective length and it is analyzed using the commercially available finite element software ABAQUS. The performance of the model is validated by comparing the behavior of the T-stub from the numerical simulation with the behavior of the connection as a whole. The moment-rotation curve of the T-stub obtained from the numerical simulation is compared with the behavior of the whole extended end-plate connection, obtained by numerical simulation, experimental tests and analytical approach. [ABSTRACT FROM AUTHOR]

This paper deals with the development and approbation of a computational model of damage accumulation in a vertical steel tank at the non-uniform foundation subsidence. The object of research is structure behavior at the survivability stage, namely, the character and sequence of damage initiation and accumulation (elastic-plastic strain, bottom and wall buckling) in the tank structure. [ABSTRACT FROM AUTHOR]

Influence of solar radiation and Earth’s radiation, as well as heat radiation of devices and on-board equipment on the deformation of the primary structure of the small spacecraft Aist-2D on the orbital flight stage is considered in this paper. The thermoelasticity problem is solved by the finite element method in the ANSYS® software. The results of the analysis are presented in the form of graphs of variation over time of the relative rotation angles of the sensors of the orientation system and optical equipment. [ABSTRACT FROM AUTHOR]

The lobule is the structural unit of the liver. In this paper a multi-physical model of blood flow in the liver lobule is considered. The proposed model is built on the basis of a double porosity model for the process of blood flow which is coupled with linear elasticity for deformations. The computational algorithm is based on finite-element approximation in space and explicit-implicit approximation in time which is a splitting scheme by physical processes. Results of numerical experiments are demonstrated. [ABSTRACT FROM AUTHOR]

In aircraft gas turbine engine, the rotating turbine disc is highly stressed component. The demand of high strength to weight ratio for each component of aeroengine makes the disc, a critical component from design point of view. Burst of rotor disc is one of the catastrophic failure mode of gas turbine engine. The present paper, therefore, deliberates the burst of rotating turbine disc due to overspeed. A typical gas turbine disc is modeled and elastic-plastic analysis is carried out by linearly increasing the speed. Finite element technique has been used for the analysis. The burst criteria is proposed based on the deformation taking place in the disc. A safe permissible speed between burst rotation speed and maximum allowable speed of the turbine disc is also identified as per federal aviation regulations. [ABSTRACT FROM AUTHOR]

Traffic accidents are terrible scourge that occurs in many countries, for developing countries where transportation problems seem like a tangled yarn. Besides its function as an engine compartment cover, the hood of modern compact SUV can also help to manage the impact energy of pedestrian's head in a vehicle-pedestrian impact. This paper presents a compact SUV's outer hood design that has a potential to improve hood ability and also to absorb the impact energy of a pedestrian's head. The developed methodology for the design of a hood configuration aims to provide a compatible design and stress distribution for the left side impact position at WAD 1000 with three different thicknesses (1.25 mm, 1.30 mm and 1.50 mm) of outer hood panel of local compact SUV, taking into consideration the limited space available for deformation. Finite Element Modeling (FEM) software was used in this research to simulate the ANCAP for child pedestrian head impact testing procedures. The results show that the minimum deformation space and meet the requirement for stress (von Mises) value are required to obtain a sturdy design. Moreover, the hood thickness and materials are the main factors that influence stress and deformation value. Finally, 1.25 thickness aluminum alloy is recommended for vehicle hood component and the pedestrian safety. [ABSTRACT FROM AUTHOR]

In this paper the reliability assessment of buckling resistance of steel beam is presented. A number of parameters such as: the boundary conditions, the section height to width ratio, the thickness and the span are considered. The examples are solved using FEM procedures and formulas proposed in the literature and standards. In the case of the numerical models the following parameters are investigated: support conditions, mesh size, load conditions, steel grade. The numerical results are compared with approximate solutions calculated according to the standard formulas. It was observed that for high slenderness section the deformation of the cross-section had to be described by the following modes: longitudinal and transverse displacement, warping, rotation and distortion of the cross section shape. In this case we face interactive buckling problem. Unfortunately, neither the EN Standards nor the subject literature give close-form formulas to solve these problems. For this reason the reliability of the critical bending moment calculations is discussed. [ABSTRACT FROM AUTHOR]

Over the past 60 years, the finite element method has been very successful in modelling deformation in engineering structures. However the method requires the definition of constitutive models that represent the response of the material to applied loads. There are two issues. Firstly, the models are often difficult to define. Secondly, there is often no physical connection between the models and the mechanisms that accommodate deformation. In this paper, we present a potentially disruptive two-level strategy which couples the finite element method at the macroscale with cellular automata at the mesoscale. The cellular automata are used to simulate mechanisms, such as crack propagation. The stress-strain relationship emerges as a continuum mechanics scale interpretation of changes at the micro- and meso-scales. Iterative two-way updating between the cellular automata and finite elements drives the simulation forward as the material undergoes progressive damage at high strain rates. The strategy is particularly attractive on large-scale computing platforms as both methods scale well on tens of thousands of CPUs. [ABSTRACT FROM AUTHOR]

The paper deals with the problem of identification of microstructure evolution model on the basis of two-step compression test. This test is characterized by non-uniform fields of strains, stresses and temperatures in the deformation zone. Therefore, the inverse approach with finite element model for the experiment - direct problem, was applied to eliminate the influence of these inhomogeneities. Inverse solution for two-step compression test is time consuming. Thus, sensitivity analysis was performed and an influence of the parameters of the microstructure model on the goal function defined in the inverse solution was evaluated. Data generated for sensitivity analysis was reused in the inverse approach to reduce the computation costs of identification. [ABSTRACT FROM AUTHOR]

The application of laminated sandwich composite in machine structures is attractive due to the low specific and tailorable properties of the composites. As such a study on the parametric instability that often occurs in machine structures should be crucially conducted on composite plates. In this paper, finite element method (FEM) has been used to model laminated composite plate subjected to periodic compressive loading for the parametric instability analysis. The FEM formulation is based on the first order shear deformation theory. Eight noded serendipity element that requires 5 degrees of freedom per node is used in this study. The developed Mathieu-Hill type equation that represents the parametric instability of the composite plate has been solved using the Bolotin's method that reduces the Mathieu-Hill equation to a couple of eigen-value problems. The FEM source codes have been developed to determine the instability charts for several configurations of composite plates. While the formulation and codes have been found to give results that agree well with past results, it has been also been found that as the static load factor is increased, the frequency center for dynamic instability region is shifted to the left while the degree of instability is increased. [ABSTRACT FROM AUTHOR]

The paper deals with the development of the technique for J-integral computation using the vector fields obtained by digital image correlation method. The proposed computing algorithm includes several steps following each other: (i) construction of displacement vector field; (ii) calculation of deformations and stresses; (iii) calculation of the J-integral value. A comparative study of the results obtained by the proposed technique and by finite element simulation was carried out. The errors of the data modeled in the ANSYS from the computed J-integral values were estimated at various tensile loads. [ABSTRACT FROM AUTHOR]

This work describes a method of applying residual stress within micro fin model to understand the deformation of the fin machined by wire electrical discharge machining (WEDM). Firstly, transient temperature distribution on a workpiece caused by WEDM discharges was calculated using finite element method (FEM). Then, the result was used to calculate the residual stress. It was found that the residual stress in the radial direction, σr (z) along the centre axis of each discharge crater was distributed non-linearly in thickness direction from the crater top surface. Then, based on structural analysis, the σr (z) was imposed within the micro fin model. Here, thermal stress field caused by series of sequential discharges was considered. The summation of calculated deflections after three sequential discharges was approximately equal to the measurement result. As a result, the non-linear distribution of σr (z) was found to be the main reason that causes the non-uniform bending of the micro fin. [ABSTRACT FROM AUTHOR]

The study represents the analysis of numerical simulation of the failure of aluminum targets made of highly porous or solid 2024 alloy under dynamic loading. The calculations employed the finite elements method in threedimensional formulation with the use of proprietary programs. The article presents the results of the numerical simulation of Taylor's test for the projectile made of highly porous aluminum 2024 alloy at the velocities of 75 to 175 m/s. These results are in a good agreement with the results of the experiments. The peculiarities of the destruction of highly porous aluminum targets are shown. [ABSTRACT FROM AUTHOR]

The article presents an effect of a blast wave on the replacement light armoured wheeled vehicle. The aim of these activities is to verify the application of additional outer protection structure on reduction of the floor plate deformation resulting from detonation of explosive material under the vehicle. During the tests, explosive charge is located under the vehicle, according to STANAG 4569 requirements. In order to test the effectiveness of the proposed structural solution, there were carried out numerical calculations with the use of a finite element method with ALE approach. It allowed for reflection of such processes as detonation, wave propagation, interaction with a structure and response of the additional system. [ABSTRACT FROM AUTHOR]

The article describes a method used to identify the type and size of a structural defect caused by changes in the deformation and vibration responses of the structure. The approach is based on the combined usage of high-precision nondestructive testing tools and the finite element method. The article includes simulation results of the most common damage types for a composite panel. Resonant forms and vibration frequencies of the panel with various damage types are presented. Patterns of changes in vibrational responses of the structure depending on the size of the defect and the nature of damage have been identified. Recommendations are given as to how the most informative vibration forms of an object can be chosen in different cases location of a damaged area. [ABSTRACT FROM AUTHOR]

Fracture of solids is considered from the viewpoint of wave dynamics derived from a field theory. Based on the principle known as the symmetry of physical laws, the present field theory describes deformation and fracture on the same theoretical basis. From experimental observations, fracture is classified into two types; the first type characterized by decaying displacement waves that initially travel and eventually become stationary, and the second type characterized by shear-bands that are initially dynamic and eventually become stationary. The field theory interprets that the decaying displacement wave represents elasto-plastic deformation dynamics and that the shear band indicates solitary wave dynamics associated with strain concentration. In either case, the theory explains that the termination of wave propagation causes infinite volume expansion that generates material discontinuity. From the wave dynamical viewpoint, fracture is a self-driving phenomenon where the decrease in the elastic constant in a late stage of deformation induces instability in oscillatory dynamics which leads to exponential increase in the volume expansion with time. The theory indicates that in this mechanism fast pulling rate enhances the instability. Simple numerical analysis with finite element modeling supports this argument of instability and its association with the pulling rate. [ABSTRACT FROM AUTHOR]

Deformation of reinforced square plate under external pressure is considered. The averaged fourth-order partial differential equation for the plate deflection w is obtained. The new mathematical model of the plate is offered. Asymptotic averaging and Finite Elements Method (ANSYS) are used to get the values of normal deflections of the plate surface. The comparison of numerical and asymptotic results is performed. [ABSTRACT FROM AUTHOR]

Anisotropic material deformation is modeled with the application of the finite element method. Hill's yield criterion is used for simplified conditions of the upsetting process. The largest flow stress direction is determined to be parallel to all the three coordinate axes by turns. It is discovered that the base of the cylinder can take an oval shape when the flow stress directions of various values lie in the base plane. In this case, the smaller axis of the oval corresponds to the largest flow stress direction. When the flow stress directions of various values lie in the longitudinal section plane of the workpiece, its shape remains cylindrical. The deformation load is higher in this case. [ABSTRACT FROM AUTHOR]

Roll deformation is an extremely important problem in strip rolling, all the more as the strip is thinner. It results in profile defects (the strip thickness varies in the transverse direction) and flatness defects (the strip exits the rolling mill wavy). This becomes a more and more stringent issue for modern, harder steels such as Advanced High Strength Steels (AHSS). Numerous compensation techniques are used, alone or in combination: roll grinding crown, 4- or 6-Hi mills, cluster mills, with shiftable tapered rolls, CVC-shaped rolls (Continuously Variable Camber), pair-cross stands, etc. Elaborating the correction strategy for a specific strip rolling operation requires a model of the action of these profile and flatness actuators. A hybrid model was developed in which the roll stack deformation is modelled with a commercial Finite Element Method (FEM), coupled with a Multi-Slab model for strip deformation. This new model allows simulating virtually any type of rolling mill configuration at a reasonable cost (CVC, shiftable rolls, pair cross stands, cluster mills) including cases of incoming strip with defects (crown or wedge), by virtue of the FEM generality and versatility. The example taken here is a 6-high rolling mill with shiftable intermediate rolls (an anti-symmetric configuration). Results show quick convergence of FEM ↔ Multi-Slab iterations and good agreement with experiments. [ABSTRACT FROM AUTHOR]

Meso-FE modelling of 3D textile composites is a powerful tool, which can help determine mechanical properties and permeability of the reinforcements or composites. The quality of the meso FE analyses depends on the quality of the initial model. A direct method based on X-ray tomography imaging is introduced to determine finite element models based on the real geometry of 3D composite reinforcements. The method is particularly suitable regarding 3D textile reinforcements for which internal geometries are numerous and complex. The approach used for the separation of the yarns in different directions is specialized because the fibres flow in three-dimensional space. An analysis of the image's texture is performed. A hyperelastic model developed for fibre bundles is used for the simulation of the deformation of the 3D reinforcement. [ABSTRACT FROM AUTHOR]

Soil is one of the most complex materials including several characteristics which are not only effect on stressstrain relationship but also volume changed such as contraction and dilation. Those characteristics depend on so many factors such as stress history, drained condition, current effective stress state, stress paths as well as void ratio, etc. In finite element analysis, the relevant constitutive model which includes relevant factors as mentioned above is one of the main key that will provide the accurate predicting of strength and deformation characteristic of geotechnical structure. For modern finite element program, the user-defined material subroutines have been provided when the material models included in the material library could not accurately predict the rather complex behavior of material. The objective of this study is to implement the elasto-plastic work-hardening-softening constitutive model into ABAQUS via VUMAT subroutine. The simulated results were verified by the experimental results of Toyoura sand under plane strain condition. [ABSTRACT FROM AUTHOR]

The interaction between the road surface and vehicle's tire may significantly determine the stability of a vehicle. We could study the tire contact-pressure to road surfaces through a numerical simulation in this present study. In particular, the main purpose of the study was to present an illustration of the effect of the varied loads to the tire, which would affect the contact pressure on the road surface sand stress distribution on the tire by employing a commercial ABAQUS software, based on the finite element method. To make the process of data analysis easier, the tire was assumed to be made from natural rubber which composition consisted of 2 layers of the inner tire and 1 layer of carcass. In pre-conditions, the tire was given air pressure as much as 17 psi, and loads as much as 2 KN, 6 KN, and 10 KN; then, the air pressure was increased to be 30 psi; consequently, the simulation results of stress distribution and deformation on each of loads condition would be acquired. The simulation results indicated that the loads carried by the tire on the vehicle were an important factor to determine the tire-stress profile. [ABSTRACT FROM AUTHOR]

Due to the rapid development of urbanization and the need for effective transportation, it became a common application to construct subway tunnels in modern cities. However, these construction activities may lead to undesirable deformations on the adjacent buildings. In this study, the effect of tunnel horizontal distance on the deformations of an adjacent building is investigated using 2D finite element analysis. The results of the finite element analysis showed that, although high settlement values were not observed for the cases investigated in this study, the vertical deformations of the building decreased as the tunnel moved away from the building. [ABSTRACT FROM AUTHOR]