A Modified Conjugate Gradient Method for Frictionless Contact Problems

1983 ◽  
Vol 105 (2) ◽  
pp. 242-246 ◽  
Author(s):  
W. R. Marks ◽  
N. J. Salamon
Keyword(s):  
Finite Element ◽  
Conjugate Gradient ◽  
Solution Method ◽  
Contact Region ◽  
Contact Problems ◽  
Computer Code ◽  
Frictionless Contact ◽  
Elastic Bodies ◽  
Gradient Technique ◽  
Modified Conjugate Gradient Method

The solution of elastic bodies in contact through the application of a conjugate gradient technique integrated with a finite element computer code is discussed. This approach is general, easily applied, and reasonably efficient. Furthermore the solution method is compatible with existing finite element computer programs. The necessary algorithm for use of the technique is described in detail. Numerical examples of two-dimensional frictionless contact problems are presented. It is found that the extent of the contact region and the displacements and stresses throughout the contacting bodies can be economically computed with precision.

An adaptive finite element approach for frictionless contact problems

2000 ◽  
Vol 50 (2) ◽  
pp. 395-418 ◽  
Author(s):  
Gustavo C. Buscaglia ◽  
Ricardo Dur�n ◽  
Eduardo A. Fancello ◽  
Ra�l A. Feij�o ◽  
Claudio Padra
Keyword(s):  
Finite Element ◽  
Contact Problems ◽  
Adaptive Finite Element ◽  
Frictionless Contact ◽  
Finite Element Approach ◽  
Element Approach

An Elasto-Plastic Finite Element Analysis of the Hat-Type Drawing Process of Sheet Metal

2006 ◽  
Vol 505-507 ◽  
pp. 709-714
Author(s):  
Tsung Chia Chen ◽  
You Min Huang
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Moving Boundary ◽  
Contact Problems ◽  
Computer Code ◽  
Plastic State ◽  
Process Conditions ◽  
Drawing Process ◽  
Forming Process ◽  
Element Analysis

This study aims to clarify the process conditions of the hat-type drawing of a sheet metal of steel. It provides a model that predicts not only the correct punch load for drawing, but also the precise final shape of products after unloading, based on the tensile properties of the material and the geometry of the tools used. An elasto-plastic incremental finite-element computer code, based on an updated Lagrangian formulation, was developed to simulate the hat-type drawing of sheet metal. In particular, selective reduced integration was adopted to formulate the stiffness matrix. The extended r-minimum technique was used to deal with the elasto-plastic state and contact problems at the tool-metal interface. A series of simulations were performed to validate the formulation in the theory, leading to the development of the computer codes. The whole deformation history and the distribution of stress and strain during the forming process were obtained by carefully considering the moving boundary condition in the finite-element method. Results in this study clearly demonstrated that the computer code for simulating the hat-type drawing process was efficient.

Contact Problems of Two Dissimilar Anisotropic Elastic Bodies

1998 ◽  
Vol 65 (3) ◽  
pp. 580-587 ◽  
Author(s):  
Chyanbin Hwu ◽  
C. W. Fan
Keyword(s):  
Boundary Conditions ◽  
Contact Region ◽  
Complex Function ◽  
Contact Problems ◽  
Anisotropic Elasticity ◽  
Analytical Continuation ◽  
Two Dimensional ◽  
Different Boundary Conditions ◽  
Elastic Bodies ◽  
Anisotropic Elastic

In this paper, a two-dimensional contact problem of two dissimilar anisotropic elastic bodies is studied. The shapes of the boundaries of these two elastic bodies have been assumed to be approximately straight, but the contact region is not necessary to be small and the contact surface can be nonsmooth. Base upon these assumptions, three different boundary conditions are considered and solved. They are: the contact in the presence of friction, the contact in the absence of friction, and the contact in complete adhesion. By applying the Stroh’s formalism for anisotropic elasticity and the method of analytical continuation for complex function manipulation, general solutions satisfying these different boundary conditions are obtained in analytical forms. When one of the elastic bodies is rigid and the boundary shape of the other elastic body is considered to be fiat, the reduced solutions can be proved to be identical to those presented in the literature for the problems of rigid punches indenting into (or sliding along) the anisotropic elastic halfplane. For the purpose of illustration, examples are also given when the shapes of the boundaries of the elastic bodies are approximated by the parabolic curves.

Finite Element Analysis of Rolling Contact Problems Using Minimum Dissipation of Energy Principle

1998 ◽  
Vol 65 (1) ◽  
pp. 271-273 ◽  
Author(s):  
S. K. Rathore ◽  
N. N. Kishore
Keyword(s):  
Finite Element ◽  
Contact Region ◽  
Contact Problems ◽  
Rolling Contact ◽  
Element Analysis ◽  
Energy Principle ◽  
Dissipation Of Energy ◽  
Rolling Surface ◽  
Strain Stress

In steady rolling motion, the loads and the fields of strain, stress, and deformations do not change with time at the contact region, as the contact region is continuously being formed by a new rolling surface. The principle of minimum dissipation of energy and the concept of traveling finite elements are made use of in solving such problems and the determination of micro-slips. The conditions of contact are discovered by use of the kinematic constraints and the Coulomb’s law of friction. A two-dimensional plane-strain finite element method along with the iterative procedure is used. The results obtained are in good agreement with expected behavior.

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