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This paper deals with a slat chain conveyor for the transport of rock materials in very severe abrasive conditions. An actual case from practice is discussed and analysed. To clarify the fatigue damage of the chain link material, the finite element method (FEM) is applied. For the experimentally recorded cycle of chain loading, numerical analysis has been performed and data for the damage of the link material are presented. Fatigue analysis is performed by ANSYS nCode DesignLife under different loading cases. FEM results show, that the fatigue crack of the link starts from region with high values of the stresses, established by experiment. [ABSTRACT FROM AUTHOR]

A finite element analysis on crash box of an automotive bumper system is presented in the paper to investigate the energy absorption of the component with and without foam-filled steel sheet metal tubes of different thicknesses for crashing or low-velocity impact analysis. The energy absorption capacity of the crash box for crashing is evaluated for different design changes of the foams-tube structure and compared the results without foam. By changing the different foam materials, various designs are proposed and simulated for maximum energy absorption. Altair Hyperworks is used for preprocessing and post-processing and Radios solver is used to run the analysis. A reasonable agreement is obtained in the results of the analytical and numerical methods. The results indicate that the energy absorption of a foam-filled crash box structure is superior to the crash box without foam. [ABSTRACT FROM AUTHOR]

The following paper aims to provide a detailed analysis of the effect of different cutting speeds in the face milling of AISI 1045 steel using coated tool. Simulations would aid in solving problems associated with experiments, leading to reduced costs and risks. DEFORM 3D is a commercially used simulation software capable of implementing machining simulations using the theory of finite element modelling. A conventional DEFORM 3D milling model has been prepared for the analysis of cutting forces and chip formation and the simulation has been carried out for two conditions. The temperature and force parameters were analyzed after carrying out the experiment and simulation under the influence of different machining and environmental conditions. The results of the simulation revealed that the predicted values of FEA possess good accuracy. [ABSTRACT FROM AUTHOR]

Steel coupling beam is a substantial member in hybrid coupled walls system that greatly enhance the strength and the energy dissipation capacity of the system compared to coupled walls linked by convention reinforced coupling beams and diagonally reinforced coupling beams. To enhance these characteristics even more, a corrugated web may be used instead of the traditional flat web. This paper presents a numerical analysis using finite elements software (ABAQUS) to investigate the nonlinear behavior of both types of steel coupling beams (with flat web and with corrugated web). The effect of initial imperfection on the nonlinear behavior of steel coupling beams was taken into account. The results were compared with the available experimental data of steel coupling beams with the flat web. Good agreement was noticed between the experimental and the numerical results. Among the conclusions drawn in this study is that using a corrugated web as an alternative to a flat web may increase both the strength and the energy dissipation of the steel coupling beams. [ABSTRACT FROM AUTHOR]

This paper is devoted to numerical analysis of plaster detachment and numerical experiments for determination of the appropriate material parameters. Interaction between the plaster and masonry is described with the help of interface finite elements which are equipped with traction-displacement relationship. Laboratory tests were introduced in order to determine the shear capacity of the masonry-plaster connection. Unfortunately, variability of measured behaviour was very large and additional tests are needed. [ABSTRACT FROM AUTHOR]

Members of double-symmetrical open cross-sections are widely used as columns in steel structures. In many cases columns are subjected not only to axial force but also local transverse force due to effect of beams connected to the columns. It results in compression in the column web that should be verified in the structural design. Current standard for design of joints in steel structures provides basic information for verification of this joint component. The design resistance of column web in compression is given as yielding resistance or, based on relative slenderness of the web, buckling resistance which takes into account buckling and crippling of the web that are considered using reduction factor. The complex behaviour of the column web in compression is affected by number of aspects, e.g. structural solution of the joint (bolted, welded, with or without end plate), level of normal stress resulting from axial force or possible interaction with shear. The paper focuses on selected aspects influencing the resistance of the column web in transverse compression and summarizes results of advanced geometrically and materially nonlinear numerical analysis which are compared with results determined using provisions in the standards. The numerical analysis was performed using computation system based on finite element method. As it is considered that the resistance of the column web in transverse compression is influenced also by the geometric properties of the cross-section including geometry of the flange-web transition, both rolled and welded cross-sections with various values of web slenderness were selected for the analysis. Along with evaluation of the results obtained in the frame of the study, suitability of different types of numerical models for investigation of this problem is discussed. [ABSTRACT FROM AUTHOR]

Since the first paper published in 2005 Isogeometric Analysis (IGA) has gained strong interest and found applications in many engineering problems. Despite the advancement of the method, there are still far fewer software implementations comparing to Finite Element Method. The paper presents an approach to the development of data structures that can support multi-region IGA with local mesh refinement (patch-based) and possible application in IGA-FEM models. The purpose of this paper is to share original design concepts, that authors have created while developing an IGA package, which other researchers may find beneficial for their own simulation codes. [ABSTRACT FROM AUTHOR]

This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure "Vumat" which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process. [ABSTRACT FROM AUTHOR]

Castellated beams are well contemporarily ascribable to their structural applications. The Castellated beams are manufactured by fragmenting hot-formed rolled section that is of I shape in then it is welded together. The numerical analysis is performed using ABAQUS software. Consequently flexural, shear behavior of Castellated beams, various size and shape of openings provided, depth of openings, usage of different kinds of stiffeners, columns with and without web openings are the attempts made up in different journal papers and he researchers. It is also found that the Finite element analysis of the beam shows better results. [ABSTRACT FROM AUTHOR]

The vortex rope in a hydro turbine draft cone is one the main and strong sources of pulsations in non-optimal modes of hydro turbine operation. The subject of this paper consists in development of a numerical procedure to study the absolute/convective hydrodynamic instability of the swirl flow downstream the Francis turbine runner by means of parallel computing. As an alternative to classical methods as finite volume and finite element methods, the present paper proposes a new approach of the analysis of the swirling flow based on the method of orthogonal decomposition. This method has the benefit of reducing the computational time compared to other techniques. The important point of this paper is that highlights the validation of the numerical results computed by means of the proposed technique with corresponding published results. Moreover, the algorithm provided the growth rate curve as function of mode number both in absolute and convective analysis, some presumptions on the streamwise development of the instability in the vortex thus being made. [ABSTRACT FROM AUTHOR]

A type of capacitance probe performance with two brass electrodes intertwined on the outer wall of insulation pipe like a double helix is investigated numerically in this paper, which can measure water fraction in air-oil-water two or three-phase flow in oil industry. The motivation of this paper is to optimize this kind of probe to improve its electric response and spatial resolution and so a 3-D numerical simulation using finite element method is employed to evaluate the effect of electrodes configuration of this capacitance probe on measuring water fraction in horizontal pipes. The electrostatic field of the probe is preliminarily analyzed referred to stratified flow of air-water two-phase flow regime. Several parameters are considered as main variables which have an important effect on the precision of the probe, such as central angle, position angle and length of the two electrodes. From the electrostatic field analysis, lumped capacitance between the two electrodes is obtained in every different electrode geometry model and the results of each model are compared to each other in order to select a better arrangement of the electrodes that has a better response to water fraction. And by using circuit simulation method, the numerical calculated lumped capacitance is transferred to voltage output through the circuit used in the experiment. The relationship between voltage and water fraction of calculated and experimental result are compared in order to test the reasonableness of the simulation. The results show that at high water fraction, the difference between numerical and measured data agrees very well. [ABSTRACT FROM AUTHOR]

This paper deals with the simulation of UNS A92024 aluminium alloy cutting processes. In particular, 2D and 3D Finite Element Method (FEM) simulations were carried out in order to estimate cutting forces and chip morphology during turning operations. The material is modelled with two different set of parameters for the Johnson-Cook's (J-C) constitutive equation and a failure Cockroft and Latham's model exploited considers damage. The comparison between the predicted chip morphology and principal cutting forces at varying of J-C parameters and cutting regimes with those experimentally found are presented and discussed. The paper shows the importance of damage criterion in the cutting forces, during the simulation, especially in 3D. [ABSTRACT FROM AUTHOR]

The vehicle bogies of Shanghai metro line 1 began to crack just in the third year after the trains operated. More than 50 cracks occurred in the succeeding six year during the train operation. This paper evaluated the safety of the motorized bogies. First, the loading conditions imposed on the vehicle structure were calculated based on the measured data in service of the train, and compared with the original design load. Then, this paper calculated simulated the stress of the vehicle bogie by 3D FEM, and presented the distribution of every stress concentration point in Goodman fatigue diagram. The computational locations of the strength less than the safety are agreed with where cracks have happened. Finally, this paper calculated the fatigue life of the motor bracket of the bogie through S-N curve based on revised Miner theory. In conclusion, this paper think that the bogie cracks of Shanghai metro line 1 are contributed by the overburden fatigue load, and ignoring the lateral vibration load in the design of the vehicle bogie is the important cause that bogie cracks occurred far earlier than in the designed time. [ABSTRACT FROM AUTHOR]

Probabilistic fracture analyses are performed for investigating uncertain fracture response of Functionally Graded Material (FGM) structures. The First-Order-Reliability-Method (FORM) is implemented into an existing Finite Element code for FGM (FE-FGM), which was previously developed at the University of Illinois at Urbana-Champaign [2]. The computational simulation will be used in order to estimate the probability of crack initiation with uncertainties in the material properties only. The two-step probability analysis method proposed in the companion paper (Part I, [1]) is illustrated by a numerical example of a composite strip with an edge crack. First, the reliability index of a crack initiation event is estimated as we vary the mean and standard deviation of the slope and the location of the inflection point of the spatial profile of Young's modulus. Secondly, the reliability index is estimated as we vary the standard deviation and the correlation length of the random field that characterize the random spatial fluctuation of Young's modulus. Also investigated is the relative importance of the uncertainties in the toughness compared to those in Young's modulus. [ABSTRACT FROM AUTHOR]

The differential eigenvalue problem describing eigenvibrations of a simply supported beam with an attached load is investigated. This problem has an increasing sequence of positive simple eigenvalues with a limit point at infinity. To the sequence of eigenvalues, there corresponds a complete orthonormal system of eigenfunctions. We formulate a limit differential eigenvalue problem and prove the convergence of the eigenvalues and eigenfunctions of the initial problem to the corresponding eigenvalues and eigenfunctions of the limit problem as load mass tending to infinity. The original differential eigenvalue problem is approximated by the finite difference method on a uniform grid. Error estimates for approximate eigenvalues and eigenfunctions are established. The theoretical results are illustrated by numerical experiments for a model problem. Investigations of this paper can be extended to the cases of more complicated and important problems on eigenvibrations of plates and shells with attached loads. [ABSTRACT FROM AUTHOR]

The nonlinear second-order differential eigenvalue problem describing eigenvibrations of a bar with elastically attached load is investigated. The existence of an increasing sequence of positive simple eigenvalues with a limit point at infinity is established. To the sequence of eigenvalues, there corresponds a system of normalized eigenfunctions. The initial nonlinear differential eigenvalue problem is approximated by the finite element method on a uniform grid. The accuracy of approximate solutions is studied. The investigations in the present paper can be extended to the cases of more complicated and important problems on eigenvibrations of beams, plates, and shells with elastically attached loads. [ABSTRACT FROM AUTHOR]

The combination of plastic and creep analysis formulation are developed in this paper. The boundary element method and the finite element method are applied in plates in order to do the numerical analysis. This new approach is developed to combine the constitutive equation for time hardening creep and the constitutive equation for plasticity, which is based on the von Mises criterion and the Prandtl-Reuss flow. The implementation of creep strain in the formulation is achieved through domain integrals. The creep phenomenon takes place in the domain which is discretized into quadratic quadrilateral continuous and discontinuous cells. The creep analysis is applied to metals with a power law creep for the secondary creep stage. Results obtained for some models studied are compared to those published in the literature. The uncertainties in both geometric and mechanical properties are considered in order to obtain the structural response. The approach is illustrated in a plate subjected to incremental load, results show that there are high probabilities of exceeding the damage states, w, equal to 0.3, 0.6, 1.2, 1.8 and 2.4 while for values of w equal to 3.0, 3.6, 4.2, 4.8, 5.4 and 6.0 these probabilities are low. The obtained results are in good agreement and evinced that the Boundary Element Method could be a suitable tool to deal with combined nonlinear problems. [ABSTRACT FROM AUTHOR]

The main objective of the research work is to present the free vibration analysis of plates composed of one of the materials that have good performance and can be applied in many fields like buildings. Material that has such properties is Functionally Graded Material (FGM). FGM consists of a mixture of ceramics and metals through varying volume fractions, ceramic material as a heat barrier at the high-temperature side, and metal material with rigid properties and high conductivity at the low-temperature side. In this paper, the FGM plate is investigated using the finite element method. We use 3-node Triangular Mixed Interpolation of Tensorial Components (MITC3), widely used by researchers or commercial software. The MITC3 element is a triangular element that gives good performance to analyze plate problems, especially isotropic plate problems. We performed the numerical analysis to examine the performance and convergence behavior of the MITC3 FGM plate element in the case of rectangular plates with varying length to width ratios, and the results are compared with the reference solution. [ABSTRACT FROM AUTHOR]

The paper focuses on numerical solution of a nonlinear aeroelastic problem. The classical approach of linearized aerodynamic forces is compared to the numerical approximation of the coupled fluid-structure problem. In the second case the finite element method is used for solution of the incompressible Navier-Stokes equations and coupled with the non-linear motion equations of a flexibly supported airfoil. The obtained results are compared to the linearized approach approximations. The influence of the nonlinear terms is discussed. [ABSTRACT FROM AUTHOR]

In this paper, the numerical analysis and computer simulation of deep drawing process has been presented. The incremental model of the process in updated Lagrangian formulation with the regard of the geometrical and physical nonlinearity has been evaluated by variational and the finite element methods. The Frederic Barlat’s model taking into consideration the anisotropy of materials in three main and six tangents directions has been used. The work out application in Ansys/Ls-Dyna program allows complex step by step analysis and prognoses: the shape, dimensions and state stress and strains of drawpiece. The paper presents the influence of selected anisotropic parameter in the Barlat’s model on the drawpiece shape, which includes: height, sheet thickness and maximum drawing force. The important factors determining the proper formation of drawpiece and the ways of their determination have been described. [ABSTRACT FROM AUTHOR]

The paper presents a practical implementation of hybrid simulation using Real Time Finite Element Method (RTFEM). Hybrid simulation is a technique for investigating dynamic material and structural properties of mechanical systems by performing numerical analysis and experiment at the same time. It applies to mechanical systems with elements too difficult or impossible to model numerically. These elements are tested experimentally, while the rest of the system is simulated numerically. Data between the experiment and numerical simulation are exchanged in real time. Authors use Finite Element Method to perform the numerical simulation. The following paper presents the general algorithm for hybrid simulation using RTFEM and possible improvements of the algorithm for computation time reduction developed by the authors. The paper focuses on practical implementation of presented methods, which involves testing of a mountain bicycle frame, where the shock absorber is tested experimentally while the rest of the frame is simulated numerically. [ABSTRACT FROM AUTHOR]

The paper deals with numerical analysis of the DCB test configuration together with the data reduction scheme described in the ASTM D 5528 Standard for determination of the mode I fracture toughness in case of the laminated composites with mechanical couplings. Numerical analysis based on the FEM approach was performed with the Abaqus software exploiting the VCCT technique. The experiments on the DCB beams made of coupled laminates were also performed. The results show, that the distribution of the Strain Energy Release Rate can be asymmetric. A need for appropriate data reduction schemes has been revealed. [ABSTRACT FROM AUTHOR]

The paper considers the problem of coach occupant safety during crash events. The authors present a simple low-cost seat buffer concept which may mitigate the effects of frontal impact. The method of computer simulation was chosen to solve the problem efficiently. The Finite Element Method (FEM) implemented in the LS-DYNA commercial code was used. The testing procedure was based on European Commission regulations, under which vehicles move at a defined speed. Simulations have shown that seat occupants suffer serious trauma during a crash, with the head experiencing relatively high acceleration, thus resulting in an HIC36 of 1490. The installation of a protective buffer mounted on the upper part of the seat reduced the HIC36 to only 510. However, in its current form it does not meet the requirements of the regulations. Further modifications to the overlay shape and structure are essential in order to better improve the deceleration of passengers' bodies. Moreover, a detailed model of seats and their anchorage should be taken into account. A more flexible structure should provide more positive and more accurate results. [ABSTRACT FROM AUTHOR]

We present an enhancement of the multiscale finite element method (MsFEM) by combining it with the hp-adaptive FEM. Such a discretization-based homogenization technique is a versatile tool for modeling heterogeneous materials with fast oscillating elasticity coefficients. No assumption on periodicity of the domain is required. In order to avoid direct, so-called overkill mesh computations, a coarse mesh with effective stiffness matrices is used and special shape functions are constructed to account for the local heterogeneities at the micro resolution. The automatic adaptivity (hp-type at the macro resolution and h-type at the micro resolution) increases efficiency of computation. In this paper details of the modified MsFEM are presented and a numerical test performed on a Fichera corner domain is presented in order to validate the proposed approach. [ABSTRACT FROM AUTHOR]

The paper presents the mixed-mode delamination of plates made of sublaminates. To this purpose an opening load mode of delamination is proposed as failure model. The failure model is implemented in ANSYS code to calculate the mixed-mode delamination response as energy release rate. The analysis is based on interface techniques. Within the interface finite element modeling there are calculated the individual components of damage parameters as spring reaction forces, relative displacements and energy release rates along the lamination front. [ABSTRACT FROM AUTHOR]

Many soft robotic structures are developed using soft fluidic actuators, which are developed using elastomeric materials such as silicon rubber. Due to the complicated geometries and nonlinearity in the soft actuator's design, it becomes very difficult to predict their behavior analytically. Finite Element Method (FEM) analysis is a numerical technique which is utilized to predict the stress, strain, and deformation in such actuators design. In this paper, bending behavior of two soft pneumatic fingers with varying wall thickness are designed and compared. Bending angle configurations of the designed fingers are evaluated at 30 and 40 kPa of actuating pressure. The obtained results show that to achieve a bending angle of 116 degrees, finger 2 requires 40 kPa of actuating pressure whereas finger 1 requires 80 kPa. Due to low stiffness of finger 2 as compared to the finger 1, which is resulted due to thickness variation in the two designed fingers, much higher bending angle configuration can be achieved at very low pressure for the finger 2. [ABSTRACT FROM AUTHOR]

Large pneumatic structures of deploying space reflector are highly efficient and significantly advantageous due to the following reasons: significant coverage at low material usage and deployment simplicity. At the same time experimental modeling of such structures is time-consuming and costly. So, numerical analysis of such structures is very important in preliminary design. This paper presents the mathematical problem statement of stress-strain state of pneumatic structures, as well as the modal analysis results for two pneumatic reflectors of 50 and 100 meters in size applying such materials as Kevlar and thin polyamide films. The above described problems were solved by well-known nonlinear finite element method. [ABSTRACT FROM AUTHOR]

In the present paper, different numerical analyses are carried out for modelling impact events. Smooth Particle Hydrodynamics (SPH) formulations, Finite Element Method (FEM) and a coupled FEM-SPH models are performed to investigate the response of AA5083-H116 Aluminium plate subjected to low velocity impact (12.31 m/s). Dimensions of Aluminium plate is 300 x 300 x 5 mm. There are 16 types of SPH formulation are available in Ls-Dyna, however, 4 of them are recommended to use with solid structures which are Standard SPH formulation (FORM=0), Renormalized SPH formulation (FORM=1), Total Lagrangian Formulation (FORM=7) and Renormalized Total Lagrangian Formulations (FORM=8). For FEM-SPH modelling, SPH particles are modelled with renormalized SPH formulations. Johnson-Cook material model is used with Gruneisen Equation of State (EOS) for the Aluminium plate. The response to impact event of models contain maximum deflection which is validated by experimental data available in literature. The results show, Total Lagrangian behaviour and FEM-SPH coupling have good agreement with experimental data by less than 2% error. However, maximum deflection value of standard SPH formulations obtained has 18.07% error. [ABSTRACT FROM AUTHOR]

The paper deals with the interaction of reinforced concrete slab with subsoil. The subject of the paper was the processing of nonlinear analysis of the performed experiment. The specifics of the solved task include that it connects the design of concrete structures and geotechnical tasks. It was necessary to take into account the actual behavior of the concrete structure and subsoil. The experiment includes a reinforced concrete slab by dimensions 2000 x 2000 mm, 150 mm thickness. Reinforcement was used netting steel bar ⊘ 8 / 100 mm. For the research task is important, that due to cracking in the reinforced concrete slab, its stiffness bending changes. This change affects the life of the structure due to its degradation. The paper focuses on the comparison of the experiment with the numerical model in two selected load cases. For numerical modeling was used the deformation variant of the finite element method and the 30 computational model. In the computational model, the fracture-plastic material model was chosen for concrete. The Newton-Rapson method was chosen for nonlinear calculation. [ABSTRACT FROM AUTHOR]

Diffraction as well as transmission of acoustic waves by two-dimensional phononic crystals (PCs) composed of steel rods in water are investigated in this paper. The finite element simulations were performed in order to compute pressure fields generated by a line source that are incident on a finite size PC. Such field maps are analyzed based on the complex band structure for the infinite periodic PC. Finite size computations indicate that the exponential decrease of the transmission at deaf frequencies is much stronger than that in Bragg band gaps. [ABSTRACT FROM AUTHOR]

In this paper, we present a numerical procedure that can be used to model the electro-mechanical coupled behavior of the dielectric actuator domain. The equation describing the electrostatical part is given by the reduced form of the Maxwell equation and the electrostatic potential [1]. The mechanical problem is described by the constitutive equations and equilibrium equations. Using the finite element method, this technique is to divide a whole problem into sub-problems. The complexity of the original problem is therefore reduced by focusing only on areas most relevant. A finite element analysis is then performed by applying the electrostatic Maxwell pressure as Neumann boundary conditions to compute the displacements. Once the displacement is computed, the electrostatic domain or the conductor is updated. Electrostatic analysis is performed on the updated geometry and the finite element method is then used to determine the change in potential due to geometric perturbations. Once the surface charge densities are known, the new electrostatic Maxwell pressure is computed. The mechanical and electrostatic analysis is repeated until an equilibrium state is computed. The procedure is demonstrated in the paper by the solution of some two-dimensional and threedimensional problems. [ABSTRACT FROM AUTHOR]

In this paper, we see that the finite volume method (FVM) is a suitable discretization method for a degenerate diffusion operator Δf(u) in the sense that the discrete version of L1 theory of Brezis and Strauss can be applied. The function f is assumed to be continuous and non-decreasing with f(0) = 0. First, we describe some operator theoretical properties of FVM for a degenerate elliptic equation of the form u-λΔf(u) = g for λ>0 and g∈L1(Ω) under the homogeneous Dirichlet boundary condition. Consequently, we immediately deduce the generation of the nonlinear semigroup, namely, the unique existence of a time global solution to a semidiscrete (in space) FVM for a degenerate parabolic equation of the form ut-Δf(u) = 0. Then, we readily obtain stability results in L1 and L∞, and order-preserving property for finite volume solutions by the nonlinear semigroup theory. This is totally new approach to study FVM for degenerate elliptic and parabolic problems. [ABSTRACT FROM AUTHOR]

This paper presents a new method for establishing the basic equations in the novel force-based large increment method (LIM) for continuum elastoplastic problems. In LIM, unlike traditional displacement methods, the (generalised) elemental force variables are adopted as system unknowns. The equilibrium equations can then be obtained directly at every nodal degree of freedom without physical equations (i.e., constitutive equations) involved. The generalised inverse of the non-square system of equations is employed to obtain the set of solutions of the non-square matrix equations directly. A conjugate gradient procedure is then used to find the correct solution from this set of solutions by optimising the compatibility of the solution based on the fact that the correct solution should also satisfy the constitutive equations and the compatibility equations. In this paper, the generalised elemental force variables are defined based on the element nodal forces. The LIM framework is therefore successfully applied to elements based on this definition. The efficiency and accuracy of the LIM are illustrated with a few benchmark problems and the results are compared with the analytical solution and the conventional displacement-based finite element method. [ABSTRACT FROM AUTHOR]

The 2.5D finite/infinite element approach for simulating the ground vibrations by surface or underground moving trains will be briefly summarized in this paper. By assuming the soils to be uniform along the direction of the railway, only a two-dimensional profile of the soil perpendicular to the railway need be considered in the modeling. Besides the two in-plane degrees of freedom (DOFs) per node conventionally used for plane strain elements, an extra DOF is introduced to account for the out-of-plane wave transmission. The profile of the half-space is divided into a near field and a semi-infinite far field. The near field containing the train loads and irregular structures is simulated by the finite elements, while the far field covering the soils with infinite boundary by the infinite elements, by which due account is taken of the radiation effects for the moving loads. Enhanced by the automated mesh expansion procedure proposed previously by the writers, the far field impedances for all the lower frequencies are generated repetitively from the mesh created for the highest frequency considered. Finally, incorporated with a proposed load generation mechanism that takes the rail irregularity and dynamic properties of trains into account, an illustrative case study was performed. This paper investigates the vibration isolation effect of the elastic foundation that separates the concrete slab track from the underlying soil or tunnel structure. In addition, the advantage of the 2.5D approach was clearly demonstrated in that the three-dimensional wave propagation effect can be virtually captured using a two-dimensional finite/infinite element mesh. Compared with the conventional 3D approach, the present approach appears to be simple, efficient and generally accurate. [ABSTRACT FROM AUTHOR]

The dynamic response of an elastic beam attached to a spring rigid bar of two degrees of freedom is studied in this paper. The partial differential equation (PDE) describing the beam and the ordinary differential equations (ODEs) concerning the rigid bar are transformed into a homogeneous first order system of equations. The eigenfrequencies and mode shapes of the beam are determined and the problem is solved by the matrix exponential method. A numerical experiment based on true-life values of the parameters is presented. The results are verified by Finite Element (FE) code modeling. An optimization problem with respect to the system parameters is solved. [ABSTRACT FROM AUTHOR]

Motto: For the derivatives of all decent functions analytic formulas can be found but with integration this is only true for very special decent functions. The aim of our paper is to describe a new modern numerical method based on the Taylor Series Method and to show how to evaluate the high accuracy and speed of the corresponding computations. It is also the aim of our paper to show how to calculate finite integrals that are the fundamental part in signal processing, especially in Fourier analysis and how to use it for symbolic operations. It is a fact that the accuracy and stability of the algorithms we have designed significantly exceeds the presently known systems. In particular, the paper wants to concentrate, using the previous results and latest development trends, on the simulation of dynamic systems and on extremely exact mathematical computations. [ABSTRACT FROM AUTHOR]

Cavity resonators are modelled using a Maxwell eigenvalue problem. In order to obtain a reliable finite element approximation one has to carefully use an appropriate discrete finite element space. In the present paper we extend the known conditions to assure a correct approximation of the spectrum to the case where numerical integration occurs and where curvilinear boundaries are present. We present a set of sufficient conditions which are similar to the case where those so called variational crimes are absent. [ABSTRACT FROM AUTHOR]

The paper deals with the numerical solution of the nonlinear wave equation. The problem is solved by combining two methods—the generalized α-method for time discretization and the finite element method for space discretization. The nonlinear system of algebraic equations resulted from the corresponding discretization is solved by the Newton method. Newton’s method shows fast convergence and takes several iterations in each time step. The aim of the paper is to study how the use of the fixed point iteration method, instead of Newton’s method, influences the performance of finding numerical solution. As it can be concluded from the obtained results, both methods are comparable in terms of iterations while the run time of Newton’s method is higher since it requires calculating the jacobian in each time step. [ABSTRACT FROM AUTHOR]

Iterative algorithms that incorporate a numerical forward model have been typically used to solve the problem of flaw profile estimation from measured magnetic flux leakage (MFL) data. These approaches use the forward model to determine the measurement signal for a given defect profile, and obtain the desired profile by iteratively minimizing a cost function. The use of numerical models is computationally expensive, and alternative forward models are needed. This paper presents a finite element neural network (FEN) obtained by embedding a finite element model in a parallel neural network architecture that enables fast and accurate solution of the forward problem. Previous results have indicated that the FEN performance as a forward model is comparable to that of the conventional finite element method. In this paper, we investigate the applicability of the FEN to determining flaw profiles from MFL data in pipeline inspection and present results on synthetic MFL data. [ABSTRACT FROM AUTHOR]

The dynamic response of a flexible beam mounted to an elastically supported mass is the subject of study in the paper. The Finite Element Method is used for transforming the partial differential equation describing the transverse vibrations of the beam into an ODE system to which the equations concerning the mass-spring system are added. The matrix exponent method is applied for the solution of the equations. A numerical example is proposed. [ABSTRACT FROM AUTHOR]

In this paper, a two phase model to compute liquid-liquid flows is presented. We consider that one phase is a highly viscous thermodependent liquid (polymer phase), whereas the second one is a low viscosity low temperature fluid (water). The first part of this paper concerns capture of the interface between the water and the polymer (or determination of the phase field function). Classical VOF and Level set techniques have been implemented and were ameliorated using mesh adaptation techniques. To accurately determine the velocity field, a two-phase formulation is considered, based in the theory of mixtures, and we introduce a scalar parameter, the phase fraction quantifying the presence of each phase in each point of the computational domain. A friction type coupling between both phases is retained. Using the mixed finite element method within an eulerian framework, we calculate in a single system the whole kinematic variables for both liquids (velocity and pressure of each phase). Results are shown, for 2D and 3D parts. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Asymmetric Incremental Forming exalts the advantages of Incremental Forming process since no dies are strictly necessary. In this way complex geometries may be manufactured with a very simple clamping equipment. On the other hand, this characteristic determines some intrinsic drawbacks which penalise its industrial suitability; first of all, the dimensional control of the manufactured part is a still open point for researchers all over the world. Several approaches have been already proposed in the last years to solve the problem, resulting only in partial solutions. At the same time, up to now, the numerical simulation did not supply significant aid to the designers, due to the problem complexity and the very long simulation time when an elasto-plastic analysis has to be carried out. For this reason an experimental trial and error approach is often preferred. An innovative approach is represented by the application of numerical analysis based on a coupled explicit-implicit formulation. In this paper, some results of a wide research on the application of explicit-implicit code for the dimensional accuracy analysis are proposed. Both the problems related to the dimensional accuracy and springback phenomenon after the manufacturing step and the trimming operation are analysed from an experimental and a numerical point of view. In this way, some relevant issues, as well as the FEM capability, have been derived by the comparisons with the experiments. All the details are widely discussed in the paper. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper deals with some numerical simulation and experimental tests related to forming and springback of a U-shaped part manufactured from tailor welded stripes. Final shape of the formed part manufactured by tailor welded stripes is seriously affected by springback effect. The materials tailored in the welded stripes have different springback values. This paper work is trying to prove out the important role of material rolling direction has on the springback reduction. The influence of the material rolling direction on the tailor welded stripes springback is examined using the simulation by finite element method (ABAQUS). Experimental tests have been done using different material rolling direction and maintaining constant all other parameters. The resulted parts were measured using a 3D scanning machine. An optimum material rolling direction is established and the results are presented in the final section of this paper. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The work presented in this paper is part of a more extensive study the aim of which is to build a complete simulation of the clinching process and subsequent resistance tests. This paper focuses on finite element analyses -that are performed with the ABAQUS™ code- of the resistance of clinched points to shear test. These analyses are run up to propagation of metal sheet fracture. A simplified procedure is proposed to identify the fracture initiation and propagation models that are used to simulate this failure process. This identification process is based on Lemaitre’s ductile damage model. The numerical simulations of a shear test have been compared to experimental results. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Among the machining errors generated in the peripheral milling the dimensional accuracy and surface roughness play a fundamental role in the quality of the machined component in the automotive and aerospace industry. The inadequacy of the surface roughness and the imprecision of the dimensional accuracy brings to the rejection of the part that causes financial loss and productivity slowdown. In this paper an analysis of the machining errors due to the cutting forces in peripheral milling was performed by means of a numerical model based on the finite element method. The dynamic cutting forces distribution were evaluated for several cutting conditions that varied with the effective rake angle, the axial depth of cut, the radial depth of cut and the feed per tooth per revolution. The model was tested with the cutting forces measured by Yucesan and Altintas in field trials on a titanium alloy. An analytical model furnished by Liu et al. and calibrated with the Yucesan’s results gave a benchmark to the discussion of the results of this paper. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Corner fill is a simple benchmark intended to gain knowledge of tube hydroforming and to evaluate hydroforming parameters. In corner fill, an originally round tube is put into a cylindrical die with square cross-sections. Under applied internal pressure, the tube expands in and fills the corners of the die. Corner fill has been studied by using finite element method. The analyses, however, failed to correctly predict the burst of the tube. In this paper, a two-dimensional implicit-static plane strain finite element model is used to study the important mechanical parameters of deformation, including shear deformation and thickness stress, of the tube. The purpose of this paper is to try to explain why the existing failure criteria, including the forming limit diagram and plastic strain criterion, cannot correctly predict burst failures in corner fill. In particular, quantitative values were obtained for shear deformation and thickness stress in a corner filled tube. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper has tried to apply the response surface approximate method in the structural optimization techniques to develop aluminum beverage can ends. Geometrical parameters of the end shell are selected as design variables. The analysis points in the design space are assigned using an orthogonal array in the design-of-experiment technique. Finite element analysis code is used to simulate the deforming behavior and to calculate buckling strength and central panel displacement of the end shell under internal pressure. On the basis of the numerical analysis results, the response surface of the buckling strength and panel growth are approximated in terms of the design variables. By using a numerical optimization program, the weight of the end shell is minimized subject to constraints of the buckling strength, panel growth suppression and other design requirements. A numerical example on 202 end shell optimization problem has been shown in this paper. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

It is possible thermal expansion from heat generation by slicing deforms a single-crystal silicon ingot but the authors can find no report on the point. In addition, numerical analysis is useful to clarify the mechanism of wafer warping but no paper has been reported the numerical analysis from the start to end of the wafer slicing process. The authors carried out experiments for the wafer slicing. In addition, a finite element analysis was carried out in order to solve the warping mechanism from the start to end of the wafer slicing process. The warp of wafer in the vertical direction was 6.05 μ m in the experiment whereas the warp in the finite element analysis was 5.30 μ m. The result by the finite element analysis gave good agreement with experimental one. This paper suggests that thermal expansion of the ingot has great influence on the warp of wafer. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The numerical analysis of thermal damage process proceeding in biological tissue, containing blood vessel, during laser irradiation is presented. Heat transfer in the tissue is assumed to be transient and two-dimensional with perfusion coefficient dependent on tissue injury. The internal heat source resulting from the laser irradiation based on the solution of diffusion equation is taken into account. At the stage of numerical computations the boundary element method and the finite difference method have been used. In the final part of the paper the results obtained are shown. [ABSTRACT FROM AUTHOR]

The paper is devoted to three-point bending of an I-beam with include of transvers shear effect. Numerical calculations were conducted independently with the use of the Solid Works system and the multi-purpose software package ANSYS The results of FEM study conducted with the use of two systems were compared and presented in tables and figures. [ABSTRACT FROM AUTHOR]