A BEM/FEM Framework for Simulation of a Plastic Workpiece Deformed by an Elastic Tool

1995 ◽  
Vol 117 (3) ◽  
pp. 372-377 ◽  
Author(s):  
A. J. Beaudoin ◽  
P. R. Dawson ◽  
S. Mukherjee

A solution methodology is developed for the simulation of a plastic workpiece deformed by a compliant tool. The solution for elastic tool displacements is based on the Boundary Element Method (BEM); the viscoplastic response of the workpiece is computed using the Finite Element Method (FEM). At each time increment, tool deflections are recomputed from the elastic solution based on surface tractions developed in the previous converged solution for the viscoplastic response of the workpiece material. Tool stresses may be recovered at any point in the simulation using the BEM solution. The updated tool geometry and motion correspondingly modify the kinematic contact constraint applied in the viscoplastic solution over the subsequent time step. Application of this methodology is demonstrated for simulation of a plane strain forging operation.

2001 ◽  
Vol 29 (3) ◽  
pp. 186-196 ◽  
Author(s):  
X. Yan

Abstract A method is described to predict relative body turn up endurance of radial truck tires using the finite element method. The elastomers in the tire were simulated by incompressible elements for which the nonlinear mechanical properties were described by the Mooney-Rivlin model. The belt, carcass, and bead were modeled by an equivalent orthotropic material model. The contact constraint of a radial tire structure with a flat foundation and rigid rim was treated using the variable constraint method. Three groups of tires with different body turn up heights under inflation and static footprint loading were analyzed by using the finite element method. Based on the detail analysis for stress analysis parameters in the critical regions in the tires, the relative body turn up edge endurance was predicted.


Author(s):  
M.F. Selivanov ◽  
◽  
Y.R. Kulbachnyy ◽  
D.R. Onishchenko ◽  
◽  
...  

The procedure for solving the plane problem of the linear theory of viscoelasticity by the finite element method is described. Based on the virtual work principle and the assumption of the constancy of the strain rate at small intervals of time, the matrix form of the equilibrium equations of the finite-element approximation of a body is written. The solution procedure is described for the constitutive relations in the Boltzmann—Volterra integral form. This integral is transformed into an incremental form on a time mesh, at each interval of which the problem is solved by the finite element method with unknown increments of displacements. The numerical procedure is constructed by ununiformly dividing the time interval, at which the study is conducted. In this case, the stiffness matrix requires recalculation at each time step. The relaxation functions of the moduli of a viscoelastic orthotropic material are described in the form of the Proni—Dirichlet series. The solution to the problem of determining the change over time of the stress concentration in a body with a round hole in a viscoelastic orthotropic plate is presented. To construct a numerical solution, the three moduli of orthotropic material were written using one exponent with the same relaxation time. For these initial data, an analytic expression for the viscoelastic components of the stiffness matrix of an orthotropic plate under plain stress conditions is constructed. Numerical examples are presented for several ratios of the hole radius to the size of the plate. These results are compared with the solution obtained for an infinite plate by inverse transformation by a numerical method of the well-known analytic elastic solution.


2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Ali Triki

Based on the finite element method, the numerical solution of the shallow-water equation for one-dimensional (1D) unsteady flows was established. To respect the stability criteria, the time step of the method was dependent on the space step and flow velocity. This method was used to avoid the restriction due to the wave celerity variation in the computational analysis when using the method of characteristics. Furthermore, boundary conditions are deduced directly from the scheme without using characteristics equations. For the numerical solution, a general-purpose computer program, based on the finite element method (FEM), is coded in fortran to analyze the dynamic response of the open channel flow. This program is able to handle rectangular, triangular, or trapezoidal sections. Some examples solved with the finite element method are reported herein. The first involves routing a discharge hydrograph down a rectangular channel. The second example consists of routing a sudden shutoff of all flow at the downstream end of a rectangular channel. The third one deals with routing a discharge hydrograph down a trapezoidal channel. These examples are taken from the quoted literature text book. Numerical results agree well with those obtained by these authors and show that the proposed method is consistent, accurate, and highly stable in capturing discontinuities propagation in free surface flows.


2012 ◽  
Vol 504-506 ◽  
pp. 413-418 ◽  
Author(s):  
Zohra Sendi ◽  
Carl Labergère ◽  
Khemais Saanouni ◽  
Hedi Belhadj Salah

The Finite Element Method (FEM) is today the most widely used in numerical simulation of forming processes, due essentially to the continuous improvement of the FEM over the years and the simplicity of its implementation. However, this method has some limitations such as the distortion of elements under large inelastic deformation and the influence of the mesh on the results in several applications. The simulation of metal forming process with large plastic strain is a classical example where the successive remeshing is often the proposed solution in this case. But the remeshing raises the problems of precision and computing time. In this context and in order to avoid the remeshing process, a Meshless method is experimented in the solving of an elastoplastic problem coupled to the isotropic ductile damage. An Element Free Galerkin (EFG) method based on Moving Least Square (MLS) concept is considered in this proposal. A two-dimensional Mechanical problem was studied and solved by a Dynamic-Explicit resolution scheme where the material behaviour is based on an isotropic hardening fully coupled to ductile damage model. In a first step a parametric study is conducted in order to find the most influent parameters on the accuracy of the results. The effect of the number of nodes, of support nodes, of quadrature points, the effect of the time-step and the support domain size are analysed and optimal values are found. In a second step, the meshless results are compared with those of the finite element method and some concluding remarks relative to the accuracy and the computing time are given.


Author(s):  
E.V. Patraev ◽  
M.S. Vakulin ◽  
Y.I. Gordeev ◽  
V.B. Yasinsky

The paper deals with the design of the cutting part of complex-profile cutters with high productivity and surface quality. Numerical experiments carried out using the finite element method made it possible to determine the stresses and strains in the layer of the cut material when machining with multifaceted milling cutters of a new type and indirectly estimate the specific cutting forces. The required dimensions and shape of the cutting wedge are set with account for various geometric parameters of the cutting part, properties of the workpiece material, and cutting conditions. This made it possible to obtain a three-dimensional model of an end mill with a trapezoidal tooth and 700 cutting edges. Experimental studies also showed a change in the morphology of chips with a size of about 2 microns, which is in good agreement with the results of preliminary estimates by the finite element method. The productivity of processing with milling cutters of a new design can be improved by increasing the number of single cutting cycles up to4000–6000 s–1.


2010 ◽  
Vol 24 (15n16) ◽  
pp. 2792-2796
Author(s):  
YOUNG MOON LEE ◽  
WON SIK CHOI ◽  
JAE HWAN SON ◽  
SUN IL KIM ◽  
HEE CHUL JUNG

In metal cutting practices, for a given tool material, tool geometry is a very important element and must be carefully designed in relation to the workpiece material to be machined. Patterns of tool stress are varying with input cutting conditions; however, effects of tool geometry on tool stress are not clearly understood. The load distribution on tool face is affected by the tool geometry and this causes the change of the stress distribution on the tool.


2018 ◽  
Vol 55 (2) ◽  
pp. 179-183
Author(s):  
Ionel Iacob ◽  
Ionel Chirica ◽  
Elena Felicia Beznea

In this paper, a model of a composite plate with a central elliptical cut-out and with an initial fissure was subjected to a tension load in the finite element method (FEM) software Abaqus to observe the propagation of that crack during a certain amount of time that elapsed in the FEM analysis. Due to symmetry, only half of the plate was modeled, as a shell, and the extended finite element method (XFEM) was used for the crack. The material properties that were assigned to the plate were taken from the database of the Ansys Mechanical software. In the vicinity of the crack a finer mesh was applied to be able to better observe the evolution of the fissure and the changes of the Von Misses stress graphs for each time step of the analysis.


Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.


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