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Abstract: This paper presents a coupled particle and finite element method for fluid–shell structure interaction analysis. The Moving Particle Semi-Implicit (MPS) method is used to analyze fluid flow and the MITC4 shell element is used in the FEM analysis of the structure. This paper considers partitioned coupling between the fluid and structural solvers. In order to satisfy compatibility in the employed partitioned coupling scheme, the Neumann–Dirichlet condition is applied to both the fluid and the structure. A symplectic time integration scheme is used to preserve energy when analyzing the shell structure. If the frequencies of the shell analysis are much higher than those of the MPS fluid solver, its time integration scheme is sub-cycled. When the presented coupling scheme was applied to simulate the sloshing phenomenon in an elastic thin shell structure, fluid fragmentation and large structural deformations were observed. [Copyright &y& Elsevier]

Abstract: In this paper, we propose a two-dimensional infinite element method (IEM) for modeling elastostatic problems with imbedded geometric singularities (e.g. re-entrant corners and cracks) in an unbounded domain. In this method, the primary problem domain is subdivided into several sub-domains which are modeled using a large number of layer-wise elements. The method is formulated based on the conventional finite element method (FEM) and uses the similarity partition concept and certain matrix condensation operations. All degrees of freedom related to the sub-domain are condensed and transformed to form an infinite element (IE) with the master nodes on the boundary only. Each IE is regarded as a regular finite element, and the IE stiffness matrix is assembled into the system stiffness matrix. The corresponding time in the modeling stage, the number of degrees of freedom, and the required PC memory storage are significantly reduced for these computations. Numerical examples are presented in this paper to show the performance of the proposed method, compared with the corresponding analytical or FEM numerical solutions. [Copyright &y& Elsevier]

Abstract: In this paper we review the basic concepts to obtain a posteriori error estimates for the finite element solution of an elliptic linear model problem. We give the basic ideas to establish global error estimates for the energy norm as well as goal-oriented error estimates. While we show how these error estimation techniques are employed for our simple model problem, the emphasis of the paper is on assessing whether these procedures are ready for use in practical linear finite element analysis. We conclude that the actually practical error estimation techniques do not provide mathematically proven bounds on the error and need to be used with care. The more accurate estimation procedures also do not provide proven bounds that, in general, can be computed efficiently. We also briefly comment upon the state of error estimations in nonlinear and transient analyses and when mixed methods are used. [Copyright &y& Elsevier]

The results of research into changes in vibrations of collecting electrodes are presented in the paper. The changes come from the optimisation of geometric and dynamic parameters of the shaking down system inelectrostatic precipitators (ESP). The computational verification was carried out using the finite element method on the MSC NASTRAN package. Vibrations and accelerations of the collecting electrodes were measured. The results were used in the comparative analysis and the analysis of spectral density of acceleration power. The paper shows how calculating methods completed by measurements allow us to solve important and sophisticated practical problem. [Copyright &y& Elsevier]

A modern conceptual design of a bridge structure should be open to wide criteria to endow the structure with static, dynamic and ductile characteristics sufficient to tackle the seismic events. The fulfillment of these requirements, as well as the exploration and the verification of innovative structural schemes, can be achieved only by using refined analysis formulations and effective numerical tools.The structural scheme considered in this paper is based on two-blade slender bridge piers. This kind of pier is a structural element subdivided into two parts, each with different geometric and mechanical properties. The first part has a box section and it is very stiff while the second part is made of two flexible blades connected at the top. This scheme has two purposes: the transmission of vertical loads to the foundation structures and the possibility to allow horizontal displacements (due to thermal effects, concrete shrinkage, etc.) without the use of cinematic mechanisms.In order to evaluate the structural performance of such a bridge pier, with regards to its stiffness, strength and ductility, a nonlinear analysis is clearly required.A proper evaluation of such performance is essential in order to achieve an optimized structure, with respect to the vertical and the horizontal loads.In the present study, the structural performances of the pier are evaluated using a solid finite element formulation. In this kind of analysis one cannot forget that the real world is affected by uncertainty, and one has to keep it into account. In general, there are several ways to reach this goal, for example one can use a probabilistic approach or a fuzzy approach. In this paper the uncertainty, involved in the reliability assessment, is modeled using a fuzzy criterion. [Copyright &y& Elsevier]

Abstract: For the simulation of structural collapse using controlled explosives, the quantification of structural parameters has to be accomplished on the basis of only few data, which may additionally be characterized by vagueness, e.g. due to uncertain measurements or changing reproduction conditions. To ensure a reliable prediction of a structural collapse, next to a close to reality simulation of the complex dynamic process, this uncertainty has to be taken into account. With regard to very high computation associated with the simulation of collapses of real world structures based on conventional finite element models, this paper addresses an efficient approach for the simulation of structural collapse based on multibody models, that simultaneously allow for the investigation of uncertainty. [Copyright &y& Elsevier]

Abstract: This paper presents a numerical approach to the stationary solution of infinite Euler–Bernoulli beams posed on Winkler foundations under moving harmonic loads. The procedure proposed in Part 1 [Nguyen V-H, Duhamel D. Finite element procedures for nonlinear structures in moving coordinates. Part I: infinite bar under moving axial loads. Comput Struct 2006;84(21):1368–80], which has been applied to consider the longitudinal vibration of rods under constant amplitude moving loads in moving coordinates, is enhanced herein for the case of moving loads with time-dependent amplitudes. Firstly, the separation of variables is used to distinguish the convection component from the amplitude component of the displacement function. Then, the stationary condition is applied to the convection component to obtain a dynamic formulation in the moving coordinates. Numerical examples are computed with a linear structure to validate the proposed method. Finally, nonlinear elastic foundation problems are presented. [Copyright &y& Elsevier]

Abstract: This paper presents procedures for efficient design sensitivity analysis for shape memory alloy (SMA) structures modeled with shell elements. Availability of sensitivity information at low computational cost can dramatically improve the efficiency of the optimization process, as it enables use of efficient gradient-based optimization algorithms. The formulation and computation of design sensitivities of SMA shell structures using the direct differentiation method is considered, in a steady state electro-thermo-mechanical finite element context. Finite difference, semi-analytical and refined semi-analytical sensitivity analysis approaches are considered and compared in terms of efficiency, accuracy and implementation effort, based on a representative finite element model of a miniature SMA gripper. [Copyright &y& Elsevier]

Abstract: This paper presents a mixed finite element model for the static analysis of laminated composite plates. The formulation is based on the least-squares variational principle, which is an alternative approach to the mixed weak form finite element models. The mixed least-squares finite element model considers the first-order shear deformation theory with generalized displacements and stress resultants as independent variables. Specifically, the mixed model is developed using equal-order C 0 Lagrange interpolation functions of high p-levels along with full integration. This mixed least-squares-based discrete model yields a symmetric and positive-definite system of algebraic equations. The predictive capability of the proposed model is demonstrated by numerical examples of the static analysis of four laminated composite plates, with different boundary conditions and various side-to-thickness ratios. Particularly, the mixed least-squares model with high-order interpolation functions is shown to be insensitive to shear-locking. [Copyright &y& Elsevier]

Abstract: Using finite element models it is possible to determine the cross-over external pressure of different pipeline arrestor designs. In this paper these finite element models are discussed and validated by comparing their results with experimental determinations. The flipping and flattening cross-over mechanisms, that were previously described in the literature, are considered in the experimental validation of the numerical models. [Copyright &y& Elsevier]

Abstract: This paper concerns the numerical simulation of feedback, adaptive feedforward and hybrid (combined feedback/feedforward) control systems on the active control of vibrations of beams with Active Constrained Layer Damping (ACLD) treatments. For the simulation a 1-D beam finite element (FE) model with an arbitrary number of elastic, piezoelectric and viscoelastic layers attached to both sides of the beam is utilized. The damping behavior of the viscoelastic layers is considered by a Laplace transformed Anelastic Displacement Fields (ADF) method. The analyzed case study regards the disturbance rejection of an aluminium beam with a pair of surface mounted ACLD patches. In the design and simulation of the control system a Single-Input Single-Output (SISO) configuration with the output being the velocity at one point of the beam and the input being the control voltage applied into the piezoelectric constraining layers is considered. The case study allows to assess and discuss the outcomes and drawbacks of the feedback and feedforward controllers when used individually and the advantages of the hybrid controller. [Copyright &y& Elsevier]

Abstract: The paper is focused on 2D continuous models derived from a discrete micro-structure. A new continualization procedure that refers to the non-local interaction between variables of the discrete media is proposed. The proposed procedure covers mainly the application of two-point Padé approximations and allows us to obtain continuous models suitable for analysis of 2D lattice vibrations with arbitrary frequencies. [Copyright &y& Elsevier]

Abstract: A nonlinear large rotations beam element is presented within the framework of an energy conserving algorithm which was presented in previous works [Lens E, Cardona A, Géradin M. Energy preserving time integration for constrained multibody systems. Multibody System Dyn 2004;11:41–61; Lens E. Energy preserving/decaying time integration schemes for multibody systems dynamics. PhD thesis, Universidad Nacional del Litoral, Argentina; 2006]. Flexibility is dealt with easily in energy conserving algorithms only for finite element models with displacement degrees of freedom. However, beam models which have rotation degrees of freedom are more cumbersome to be handled. The beam model which we introduce in this paper has simplifications that lead to quite compact expressions of its different terms. This kind of algorithms has many advantages, both theoretical and practical, because of its unconditional stability which is guaranteed even in the nonlinear regime. [Copyright &y& Elsevier]

Abstract: The real spatial heterogeneity of the ground accelerations in recorded events at the SMART-1 array in Taiwan show more random variation than is assumed by SVEGM type models. Rather than employing some exponential type best-fit for the absolute coherency between two dissimilar spatial locations, real multi-station data from SMART-1 is used to generate a more detailed picture of the spatial heterogeneity present. A novel correction scheme is employed to reprocess the SMART-1 data. This paper considers the errors, in seismically induced forces, that can be accrued if identical support excitation (ISE) analysis is used in place of a multi-support excitation (MSE) analysis. A spectrum of bridge spans and spatial horizontal alignments are investigated using contoured polar response spectra. The effect of structural mode coupling is investigated. The conditions under which an ISE analysis is not conservative are reported. [Copyright &y& Elsevier]

Abstract: Slender footbridges are known to suffer excessive lateral vibration which is not well understood at present. A suspension footbridge model with reverse profiled cables is proposed to investigate the vibration characteristics of slender shallow suspension footbridges and two types of cable configurations are considered in this paper. It is found that suspension footbridges with shallow cable profiles often have coupled vibration modes which can be described by a “coupling coefficient” defined as the ratio of vertical component to the lateral one. Numerical results show that the coupling coefficient has a significant effect on the lateral dynamic amplification factor (DAF). Small coupling coefficients can induce large DAF in lateral modes. [Copyright &y& Elsevier]

A moving rail vehicle may cause propagating waves to the surroundings potentially leading to detrimental effects for the track construction, nuisances for the surroundings and interference with delicate electronic equipment. A full computational model should be able to couple a correct simulation of the rigid body motion of the different train parts with accurate prediction of the solid wave propagation in the ground. This paper integrates the dynamics of the vehicle and the elastic soil into one monolithic system. Equations of motion for the train have been merged the system representing the FEM problem for the rest of the structure. Three models of modern high-speed locomotives were run over a solid finite element model of a rail structure. [Copyright &y& Elsevier]

Abstract: This paper deals with analyzing nonlinear structures under high-speed moving loads by use of the finite element method. The stationary response of an infinite bar posed on a Winkler foundation under constant moving loads is investigated. Instead of the transient analysis, the stationary solution of this problem is obtained by solving a static system in a reference frame which moves with the load for reducing the computation cost. To overcome the difficulty due to numerical instabilities when considering very fast loads (supersonic loads), a new procedure to govern the finite element formulation in moving coordinates is proposed. Comparing numerical solutions with analytical ones shows that the proposed method is valid for all values of load speed. Last, an example of nonlinear elastic foundation is considered to outline the nonlinear effects. [Copyright &y& Elsevier]

Abstract: This paper presents a novel finite element based approach able to represent the complex architecture of the non-crimp fabric (NCF) composite materials. By means of the stiffness averaging method, implemented in the research oriented FEM (finite element method) code B2000, the developed model is able to simulate the NCFs mechanical performances. Applications to simple coupons loaded in tension are presented in order to demonstrate the capability and the effectiveness of the presented approach. Nevertheless, the proposed methodology can be applied and extended to all NCF geometries. First, for validation purposes the numerical results detained for a specific configuration have been compared with experimental results available from literature. Then, a parametric study has been carried out to investigate the influence of the bundle waviness on the tension stiffness. Finally, due to the degradation of the in-plane mechanical properties, the presence of the stitching has been investigated. [Copyright &y& Elsevier]

Abstract: The main goal of the paper is to use all the opportunities created by the wavelet analysis to model interface defects and some structural non-homogeneities in unidirectional periodic composite materials. The influence of these defects is detected by the comparison of a defected composite with the behaviour of additional composites with perfect interfaces. Some algebraic combination of the Haar wavelet, Mexican hat and harmonic wavelets is proposed to describe analytically the material properties, i.e. heat conductivity and capacity, Young modulus as well as mass density. The interface defects are simulated here as a significant decrease of any material property in the neighbourhood of a multi-material boundary inserted into the component having smaller material coefficients. The composites with and without interface defects with material characteristics so defined are compared with one another using some basic wavelet-based FEM tests of different discretisation order for transient heat transfer and free vibrations problems. The multiresolutional meshing process is completed thanks to various order meshes, where 1D two- or three-noded finite elements discretize a single representative volume element (RVE). Necessary numerical data pre-processing is carried out using the symbolic computations package MAPLE, which was developed for determination of the effective characteristics for analogous composites. Computational studies highlight the crucial role of the interface in the macro-scale behaviour of even unidirectional composites and should be extended to multiresolutional elastoplastic computational analysis, 2D and 3D analysis by the wavelet functions. [Copyright &y& Elsevier]

Abstract: In this paper, a simulation procedure for sliding tread blocks under consideration of thermal effects and abrasion is introduced. It is intended as a powerful tool in tire design and development complementary to experimental investigations. A contact model specially suited for the contact pairing rubber and rough road is developed. Subsequent changes of the model geometry in the course of the simulation allow for the reproduction of abrasion effects. The simulations are carried out by means of the Finite Element Method in a thermo-mechanically coupled manner. Exemplary simulation results are presented for 2D as well as 3D models of rubber tread blocks. By incorporation of sipes and by consideration of parallelogram-shaped bases, a close approach to realistic tread patterns is achieved. [Copyright &y& Elsevier]

Abstract: Hencky’s elasticity model based on the logarithmic strain tensor is discussed. Continuum formulation makes use of the conjugate stress tensor derived by Hoger. Constitutive equations are cast in two settings: General Lagrangean and isotropic Eulerean forms. Recent experimental data for tension, compression, simple shear and torsion loadings with the inclusion of Poynting’s effect are employed to validate this constitutive model. Subsequently, the performance of numerical methods in the finite element method context is tested. The paper closes with numerical examples, involving 60% compression test, which exhibits barreling caused by friction. [Copyright &y& Elsevier]

Abstract: Improvement of the load carrying capacity of glulam beams by the addition of reinforcement is now common practice. Recently it has been demonstrated that pre-stressing of beams using pultruded glass fibre reinforced plastic (GRP) tendons provides an available alternative due to the compatibility of the two materials and the low losses of pre-stress. This paper describes a finite element based model which was validated against test results and then used to investigate bond stress between a pre-stressed GRP tendon and the adjacent timber. Parametric studies were also undertaken to evaluate the effects of tendon thickness, beam span and the pre-tension force on the structural behaviour of beams. [Copyright &y& Elsevier]

Abstract: The theorems of structural variation predict the forces and displacements throughout a structure without the need of fresh analysis when the physical properties of one or more members are altered or even its topology is changed due to removal of one or more of its elements. It has been shown that a single linear elastic analysis of a parent structure under the applied loads and a set of unit-loading cases is sufficient to determine the elastic, non-linear elastic and even elastic–plastic response of number of related frames. These theorems later are extended to triangular, quadrilateral and solid cubic finite element structures. In this paper, the theorems of structural variation are extended to cover the rectangular finite elements for plate flexure. The unit-loading cases required to study the modification of a single element are derived. The displacements and nodal forces obtained from these unit-loading cases are used to calculate the variation factors. Multiplication of the response of the parent structure by these variation factors simply yields the response of the new structures where one or more of its members are altered or totally removed. Two examples are included to demonstrate the application of these theorems. [Copyright &y& Elsevier]

Abstract: The present paper addresses the analysis of large-scale three dimensional magneto-mechanical problems by means of a coupled boundary element–finite element procedure. Iterative techniques are used for the solution of the associated linear systems; their intrinsic ill-conditioning is cured by means of ad-hoc multigrid solvers and fast multipole techniques as accelerators. Some numerical examples are presented in order to test the performance of the proposed approach. [Copyright &y& Elsevier]

Abstract: This paper is concerned with an efficient implementation of material models suitable for the analyses of large-scale engineering problems. Based on the enhanced assumed strain concept (EAS), the final failure kinematics of solids associated with a small-scale are incorporated into the large-scale phenomenological macroscopic constitutive equations. To model the structural response realistically both plastic strains as well as damage-induced stiffness degradation are taken into account. In contrast to the original EAS concept, the parameters defining the enhanced strains are condensed out at the material level. The presented constitutive and numerical framework is applicable to a broad range of different localization phenomena including mode-I, mode-II and mixed-mode material failure. The applicability and the performance of the proposed finite element formulation is investigated by means of a re-analysis of a two-dimensional L-shaped slab as well as by means of a three-dimensional ultimate load analysis of a notched concrete beam subjected to an eccentric load. [Copyright &y& Elsevier]

This paper presented a simple technique to derive the stiffness and mass matrices of a horizontally circular curved beam element so that the possibility of practical applications of the presented property matrices should be greater than that of the existing ones. Where the element stiffness matrix was derived from the force–displacement equations and the element consistent mass matrix was derived from the kinetic energy equations. The effect of rotary inertias due to both bending and torsional vibrations and the effect of shear deformation were considered in the formulation. Since all element property matrices of the curved beam element were derived based on the local polar coordinate system (rather than the local Cartesian one), their coefficients were invariant for any curved beam element with constant radius of curvature and subtended angle. For this reason, one did not need to transform the property matrices of each curved beam element from the local coordinate system to the global one to achieve the overall property matrices of the entire curved beam before they were assembled. However, the simple transformation matrices between the local polar coordinate system and the global Cartesian coordinate system were also presented so that the element property matrices of the curved beam elements can be assembled with those of the conventional straight beam elements (or the other curved beam elements with different radii of curvatures and/or subtended angles) to achieve the overall property matrices of the entire “hybrid” structural system. The good accuracy of the presented approach has been verified by both the existing analytical (exact) solutions for the continuum curved beam and the numerical (approximate) solutions for the discretized curved beam composed of the conventional straight beam elements using either the consistent mass model or the lumped mass model. [Copyright &y& Elsevier]

This paper presents a state-space method for the calculation of dynamic response of systems made of viscoelastic materials with exponential type relaxation kernels. Equivalent first-order systems in state-space, which respectively correspond to the homogeneous and particular solutions of the viscoelastic system, are formulated and analyzed. These two equivalent systems are solved using standard state-space methods, which greatly simplifies the analysis procedure of viscoelastic systems. Numerical examples are given to demonstrate the present approach and highlight the improvement as compared to previous methods. [Copyright &y& Elsevier]

On the basis of the theory of three-dimensional elasticity, this paper presents a state space finite element solution for the stresses in cross-ply laminates subjected to combined transverse and in-plane loads. The state space formulation is introduced to solve for through-thickness stress distributions, while the traditional finite elements are used to approximate in-plane variations of the state variables. One of the direct applications of this solution is for the analysis of free-edge effect in cross-ply laminates. By appropriately describing the applied in-plane boundary tractions or boundary displacements, plates having complete free edges or boundary cross-sections with localized stress-free surfaces can be analyzed. Compared with the traditional finite element method, the new solution provides not only continuous through-thickness distributions of both displacements and transverse stresses, but also excellent approximations to the stress singularities in the vicinity of free edges or the above-mentioned localized stress-free surfaces. [Copyright &y& Elsevier]

In this paper, the use of the finite element method in conjunction with abductive network is presented to predict an acceptable product of which the minimum wall thickness and the protrusion height fulfill the industrial demand on the T-shape tube hydroforming process. The minimum wall thickness and the protrusion height are influenced by the process parameters such as the internal pressure and the die fillet radius. Different internal pressures combined with various fillet radii are taken into account as the process parameters in this study. A finite element based code is utilized to investigate the material flow characteristics under different process parameters, and the abductive network is then applied to synthesize the data sets obtained from the numerical simulation, then a prediction model is established. From the prediction model, a suitable range of the process parameters for producing an acceptable T-shape tube that fulfills the industrial demand can be found. [Copyright &y& Elsevier]