Software Package ABAQUS Research Articles

On the influence of elasticity on the large deflections response of circular plates to uniform quasi-static pressure

This work presents an approximate theory to predict the large deflections and elastic spring-back of circular plates made of elastic, perfectly plastic material when subjected to uniform quasi-static pressure. A non-linear interaction between the membrane force and bending moment is assumed when the radial displacements are included in the analysis in order to obtain realistic strain distributions. It is shown that the stored elastic energy in the plate has a limit for the particular material model when sufficiently large deflection occurs and the plate becomes entirely plastic. Therefore, the spring-back of the plate during unloading decreases with the increase of the pressure level. It is also revealed that a plate thinning occurs at sufficiently large deflections, which has a non-negligible effect on the plate stiffness. The plate deflections predicted by the proposed elastic-plastic theoretical model in the loading phase are compared with those given by a rigid-plastic analysis reported in the literature so as to estimate the loading range where the material elasticity has an important effect.In parallel, numerical simulations are conducted using the commercial software package ABAQUS to verify the proposed theoretical model. It is shown that the theoretical predictions are in good agreement with the results from the numerical simulations in terms of the pressure-displacement dependence, accumulated elastic energy, elastic spring-back and permanent displacements.

Compressive buckling strength of extruded aluminium alloy I-section columns with fixed-pinned end conditions

The compressive buckling behaviour of extruded aluminium alloy I-section columns with fixed-pinned end conditions has been experimentally and numerically investigated in this study. A total of 11 column tests, involving two heat-treated aluminium alloys – 6061-T6 and 6063-T5, were carried out to acquire the compressive buckling strengths. Prior to the column tests, material properties of the two aluminium alloys were determined from tensile coupon tests, while the initial local and global geometric imperfections were separately measured by means of experimental techniques. By using the ABAQUS software package, finite element (FE) models that could account for material non-linearity and initial geometric imperfections were developed. The FE models were further validated against the test results, enabling reliable simulation of the compressive buckling behaviour of the tested columns with fixed-pinned end conditions. Based on the obtained test and numerical results, the calculation methods in the current design standards, including the European, Chinese, American and Australian/New Zealand specifications, were all assessed. It was shown that the design provisions in all the four standards provided relatively conservative strength predictions, especially for the aluminium alloys with more pronounced strain hardening capacity.

Numerical effects on notch fatigue strength assessment of non-welded and welded components

Local fatigue strength assessment based on threshold values obtained by linear-elastic notch stress calculation is commonly utilized due to its applicability to complex geometries with an acceptable effort. As the result of a finite element computation is affected by the element type and mesh refinement, this paper investigates the numerical influence on the notch stress based fatigue strength assessment of non-welded and welded components. Based on extensive finite element studies employing the software package Abaqus it is concluded that quadratic shape functions with a number of sixteen for non-welded parts and twelve elements over a semicircle for welded joints should be at least applied to minimize the numerical impact.

Vibration analysis of foam filled honeycomb sandwich panel – numerical study

Honeycomb structures are widely used in transportation industries. Owing to their lightweight, high strength, damage tolerance and thermal resistance, they are extensively used as a solution to modern engineering problems in the vehicle structure’s design. Furthermore, lightweight polymeric foams can be exploited to improve mechanical properties of sandwich panels. Recently, foam filled honeycomb sandwich panels have been proposed in order to benefit from mechanical characteristics of both honeycomb cellular structure and polymeric foam in the core of the sandwich panel. Until now, most of the investigations were delved into the mechanical properties of the foam filled honeycomb sandwich panels; in plane crushing, out of plane impact and local indentation response of these panels were broadly discussed previously. On the other hand, since many vehicles’ failure are related to severe vibrations, clear understanding of foam filled honeycomb panels eigenvibration properties is vital. In this paper, vibration frequencies and mode shape of honeycomb sandwich panels with different cores are studied using numerical method. At the first step, elastic mechanical properties of polyurethane foams were determined by experimental tests, next a finite element model was developed by means of Abaqus software package. Parameters, such as first resonant frequency, mode shapes and influence of foams on local vibration of the honeycomb core were investigated.

Reinforced Masonry Column’s Analysis: The Influence of Rounded Corners

Numerical analysis of masonry structures is a complex task requiring deep knowledges about the problematics. This paper deals with concentrically compressed brick masonry column reinforced by fiber reinforced polymer (FRP) wrapping. The experimental research across the world has proved that FRP external sheets are an efficient tool for stabilization or strengthening of masonry structures. A combination of several types of column’s failure were observed during the experimental testing – failure in masonry, rupture of FRP sheet or failure at interface between reinforcement and masonry support. The rupture of sheet occurs close to sharp corners under the assumption of sheets’ perfect overlap. The rounded corners result in an enlargement of the FRP-masonry contact and reduction of the stress concentration. The increasing of an effective area causes a greater influence of FRP wrapping. For all 3D simulations the commercial software package ABAQUS was used and the obtained results are discussed.

Numerical analysis of flexural buckling resistance of non-uniform compression members

This paper presents parametric linear-elastic analysis of flexural buckling of idealised non-uniform member and nonlinear analysis of flexural buckling with equivalent imperfections, using software package Abaqus. The analysis includes hinged and cantileverstepped members, where the stiffness ratio of the upper and lower segments and the ratio of the values of axial forces at the top and at the change in the cross-section are varied. The aim of this paper is to define graphic and table models for determining effective lengths coefficients of non-uniform members' segments based on a relevant and reliable database that was obtained using the Finite element method. In addition, the reliability of the method for calculating the flexural stability of the compressed columns according to EC3 was evaluated in which the critical load value was determined in the previous step using the Elastic buckling analysis of idealised elements.

Numerical Modeling of Cone Penetration Test in Slightly Overconsolidated Clay with Arbitrary Lagrangian-Eulerian Formulation

In this paper the results of the cone penetration test (CPT) modeling with the arbitrary Lagrangian-Eulerian (ALE) formulation provided by Abaqus software package have been presented. The study compares the cone resistance and sleeve friction obtained in numerical analysis with values measured in soundings performed in the uniform layer of clayey soil in the Koszalin area. The clay layer was found to be slightly overconsolidated with OCR ranging from 3.5 to 4.5. The subsoil parameters used in the numerical model are based on laboratory tests data and the complementary CPT estimation. Evaluation of the most important factors influencing the numerical solution such as friction on the probe-soil interface and the undrained shear strength of the clay have been discussed. The possibilities of ALE method for soil parameters calibration are introduced and future challenges in large deformation problems modeling due to penetration issues are described.

Primena metode dinamičke krutosti u numeričkoj analizi slobodnih vibracija ploča sa ukrućenjima

The free vibration analysis of stiffened plate assemblies has been performed in this paper by using the dynamic stiffness method. Rectangular Mindlin plate dynamic stiffness element has been formulated. Using the rotation matrices, dynamic stiffness matrices of single plates have been derived in global coordinate system. The global dynamic stiffness matrix of plate assembly has been derived by using similar assembly procedure as in the finite element method. The natural frequencies of stiffened plate assemblies with different boundary conditions have been computed and validated against the results obtained by using the commercial software package Abaqus. High accuracy of the results has been demonstrated.

Study the effect of wear rate on impingement failure of an acetabular liner surface based on finite element analysis

In this study, correlation of wear inside of an acetabular liner surface (ALS) and damage on an acetabular liner rim (ALR) due to impingement effect are investigated. The analysis included evaluation of the macrostructure of the damage based on visual investigation and computer simulation analysis. A commercial finite element method ABAQUS software package is used to simulate local impingement on the ALR due to wear depth variations (wear rates) inside the ALS. Here, the wear depth is based on the data of wear experiment from literature. The von Mises stress and contact deformation on the ALR at impingement is presented. In addition, the initial impingement angle is also presented to show the correlation between the wear inside of the ALS and the angle of impingement occurrence. The results show that the existence of wear inside of the ALS can increase the damage of the ALR due to impingement effect.

A finite element method for light activated shape‐memory polymers

SummaryShape‐memory polymers (SMPs) belong to a class of smart materials that have shown promise for a wide range of applications. They are characterized by their ability to maintain a temporary deformed shape and return to an original parent permanent shape. In this paper, we consider the coupled photomechanical behavior of light activated shape‐memory polymers (LASMPs), focusing on the numerical aspects for finite element simulations at the engineering scale. The photomechanical continuum framework is summarized, and some specific constitutive equations for LASMPs are described. Numerical implementation of the multiphysics governing partial differential equations takes the form of a user defined element subroutine within the commercial software package ABAQUS. We verify our two‐dimensional and three‐dimensional finite element procedure for multiple analytically tractable cases. To show the robustness of the numerical implementation, simulations are performed under various geometries and complex photomechanical loading. Copyright © 2016 John Wiley & Sons, Ltd.

Large inelastic deformation of aluminium alloy plates in high-speed vessels subjected to slamming

This paper focuses on large inelastic deformation of plates made of marine grade aluminium alloys subjected to dynamic pressure loads that may arise from slamming. Simple design equations for predicting the permanent damage of plates are derived based on rigorous parametric studies performed using non-linear finite element method. The non-linear finite element analysis software package ABAQUS is utilised in the simulations. The impact pressure profile is idealised as a triangular pulse with linear decay. Simply supported and fully clamped boundary conditions are assumed at the edges of the plates. The aluminium alloy grade 5083-H116 is considered. The effect of the heat affected zone at the plate boundaries is also assessed. The derived simple equations are in good agreement with the finite element analysis results and therefore can be used for design purposes and serviceability limit state assessment of aluminium platings in high-speed vessels.

DEVELOPMENT OF DYNAMIC MODEL FOR VIBRATION CONTROL OF FLEXIBLE BEAM

The present study aims at developing a new dynamic model for vibration control of a composite carbon cantilever beam. The finite element method (FEM) is used to derive the introduced model. Modal analysis is performed on the cantilever beam using ANSYS software package and results were compared with similar published work using ABAQUS software package to validate the results obtained from ANSYS. The theory behind the extraction of flexible beam model from the finite element model is introduced. The eigenvalues and eigenvectors resulting from this analysis are integrated into MATLAB, which is used to derive the state space model of the system. Through MATLAB/ SIMULINK tools a PID controller was designed and controlled system performance under different system inputs is studied to test the efficiency of the controller. The results show similar responses and similar error percentage signals to various step input angles. In addition, the system shows a good performance to sine wave input signal despite the presence of a minor lag.

Elastic-plastic secondary indeterminate problem for thin-walled pipe through the inner-wall loading by three-point bending

ABSTRACTThe inner-wall loading by three-point bending about thin-walled pipe is an elastic-plastic secondary indeterminate problem in the symmetrical three-roller setting round process. In this study, the shifting of the tangent point between the pipe and lower roller is ignored. The bilinear hardening material model is adopted, and the static equilibrium condition, physical relationship of elastic-plastic deformation, and deformation compatibility condition are taken into account. Based on the geometrical discrete idea, a semi-circular pipe is meshed equably into N micro-pipe-wall elements with same geometric parameters along the circumferential direction. Deformation characteristics of each element are calculated, and then the deformation history response of the whole pipe is resolved by the load increment method. The finite element model of static bending in three-roller setting round process is established by using the software package ABAQUS. The theoretical and simulated results show that the cross section of pipe has two positive bending regions and two reverse bending regions; the maximum bending curvature appears in the bottom section of pipe, the minimum bending curvature appears in the section corresponding to the tangent point of the pipe and lower roller. The quantitative relationships between the upper roller load, maximum(minimum) bending curvature and reduction are given. Finally, the reliability of theoretical calculation is proved by numerical simulation.

Incremental elastoplastic FEM for simulating the deformation process of suction caissons subjected to cyclic loads in soft clays

This paper presents an incremental elastoplastic finite element method (FEM) to simulate the undrained deformation process of suction caisson foundations subjected to cyclic loads in soft clays. The method is developed by encoding the total-stress-based bounding surface model proposed by the authors in the ABAQUS software package. According to the model characteristics, elastoplastic stress states associated with the incremental strains of each iteration are determined using the sub-incremental explicit Euler algorithm, and the state parameters describing the cyclic accumulative rates of strains are updated by setting state variables during the calculations. The radial fallback method is also proposed to modify the stress states outside the bounding surface to the surface during determination of the elastoplastic stress states. The stress reversals of soil elements are judged by the angle between the incremental deviatoric stress and the exterior normal vector at the image stress point on the bounding surface to update the mapping centre and state variables during cyclic loading. To assess the general validity of the method, the reduced scale model tests and centrifuge tests of suction caissons subjected to cyclic loads are simulated using the method. Predictions are in relative good agreement with test results. Compared with the limit equilibrium and quasi-static methods, the method can not only determine the cyclic bearing capacity, but can also analyse the deformation process and the failure mechanisms of suction caisson under cyclic loads in soft clays.

Experimental and Numerical Analysis of Cement Based Composite Materials with Styrofoam Inclusions

In civil engineering an increasing demand for lightweight concretes exists, because a lower density results in significant benefits for structural elements. Polystyrene foams may be used in the fabrication of lightweight concretes with a large density range. In this work, the influence of fine grained sand (<1mm) additions of 5, 10 and 20% on the properties of a composite consisted of cement with styrofoam inclusions of 20, 40 and 60% has been studied. Finite element analysis (FEA), using Abaqus software package, was carried out to predict numerically the effect of particle size and polystyrene fraction on the compressive strength of the composite materials. The composites were characterized by their density, porosity and compressive strength after 28 days. The density of the composites varied between 1250 and 1600 kg/m3 with a strength of 18 and 9 MPa for 20 and 60% of Styrofoam inclusions, respectively. The increase of the fraction of sand from 5 to 20% promoted the increase in bulk density and modulus of the composites. The effect of the addition of sand on the porosity and mechanical strength exhibited variation indicating the packing factor of the particles as the main responsible for this behavior. Based on the finite element analysis the amount of the stress in the composite increases with the increasing particle diameter. The composites investigated exhibited a uniform distribution of the polystyrene spheres, allowing their use for non-structural purposes.

Experimental modal analysis of a rotor with active composite blades

This paper presents a modal analysis of a rotor with three active composite blades performed by different methods. The rotor blades were made of glass–epoxy unidirectional laminate. Active Macro Fiber Composite (MFC) elements were adhered on each composite blades. The experiments were performed on a test stand installed at a Structures Dynamics Laboratory at the Lublin University of Technology. The rotor was fixed during the measurement. A laser vibrometer and LMS analyzer with modal hammer were used. The experimental natural frequencies and mode shapes of free vibrations were determined. The laser vibrometer was equipped with a generator and scanning heads with a video camera. In order to activate vibrations, MFC elements powered by a high-voltage amplifier were used. The experimental results were developed using PSP software. Next, the LMS analyzer with modal hammer was used as force and acceleration sensor. Finally, a numerical modal analysis was performed. The simulations were performed by the finite element method using the Abaqus software package. The numerical results and the experimental findings show a very good agreement. All results were compared with the results of modal analyses for the cantilever composite beam and the fixed rotor with one composite blade.

Finite element analysis and simple design calculation method for rectangular CFSTs under local bearing forces

Rectangular concrete-filled steel tube (CFST) may be subjected to local bearing forces transmitted from brace members while being used as a chord of a truss, and thus development of finite element analysis (FEA) and simple design calculation method for rectangular CFSTs under local bearing forces are very important to ensure the safety and reliable design of such a truss with rectangular CFST chords in engineering practices. A three-dimensional FEA model was developed using ABAQUS software package to predict the performance of thin-walled rectangular CFST under local bearing forces. The preciseness of the predicted results was evaluated by comparison with experimental results reported in the available literature. The comparison and analysis show that the predicted failure pattern, load versus deformation curves and bearing capacity of rectangular CFST under local bearing forces obtained from FEA modelling were generally in good agreement with the experimental observations. After the validation, the FEA model was adopted for the mechanism analysis of typical rectangular CFSTs under local bearing forces. Finally, based on the parametric analysis, simple design equations were proposed to be used to calculate the bearing capacity of rectangular CFST under local bearing forces.

High frequency mechanical impact treatment (HFMI) for the fatigue improvement: numerical and experimental investigations to describe the condition in the surface layer

Post-treatment techniques like the high frequency mechanical impact treatment (HFMI) exhibit a significant fatigue life enhancement of welded joints. The effectiveness of this mechanical impact treatment is primarily based on the combination of three effects: the local hardness increase, compressive residual stresses and reduced notch stress concentration at the weld toe. The goal of the present study was to develop a computationally efficient approach for predicting residual stresses induced by the HFMI process on steel specimens. For that purpose, explicit simulations of this post weld treatment technique were performed utilizing the software package ABAQUS. Although, the focus of this study is to find suitable process and material parameters as input for the numerical simulation. For this, the impact velocity, contact force and permanent indentation depth of a pneumatic HFMI-tool were measured. Concerning material modelling, an enhanced combined material model with strain rate dependency was applied. Furthermore, the simulated residual stress field was experimentally validated by X-ray diffraction and neutron diffraction residual stress measurement. The results of the simulations are in good agreement with the experimental results, showing that the material hardening model used for simulation has a high influence on the calculated residual stress values.

Non-Linear Numerical Analysis of Unreinforced Masonry Column and Masonry Column Reinforced by FRP Wrapping

A numerical model for unreinforced masonry columns and masonry columns reinforced by FRP wrapping is presented in this paper. Both, the bricks and the mortar are modeled as 3D continuum and to the interface between these two materials a non-linear contact law is assigned. The accurate 3D modeling of masonry units and mortar joints within the numerical model leads to high computational cost, but on the other hand, an appropriate analysis tool delivering detailed information about the behavior of masonry columns is obtained. A concrete damaged plasticity model was adopted for mortar and brick. External wrapping by a perfectly-adherent composite based strips and contact between strips and masonry is defined in the next step. The behavior of reinforcement was assumed isotropic and linearly elastic. The response and failure mechanism of masonry columns can be investigated. For all simulations the commercial software package ABAQUS was used. By comparison with results from experiments [1], the performance of the numerical model is evaluated and the obtained numerical results are discussed.

Masonry Column Reinforced by FRP Wrapping: Behavior and Numerical Analysis

A numerical analysis for masonry columns is presented in this paper. The behavior and character of deformation of compressed unreinforced masonry columns is investigated and compared with the deformation of masonry columns reinforced by FRP wrapping. The experimental program is part of a research project NAKI [1]. Both, the bricks and the mortar are modeled as 3D continuum and to the interface between these two materials a non-linear contact law is assigned. The contact between reinforcement and masonry support is considered as perfectly-adherent. Two different cases are simulated - the ratio of Young ́s modulus of brick and Young’s modulus of mortar is 5:1, respectively 1:5. For all simulations the commercial software package ABAQUS was used and the obtained numerical results are discussed.