Bounds on plastic strains for elastic plastic structures in plastic shakedown conditions

2007 ◽  
Vol 25 (1) ◽  
pp. 107-126 ◽  
Author(s):  
Francesco Giambanco ◽  
Luigi Palizzolo ◽  
Alessandra Caffarelli
Keyword(s):  
Plastic Strains ◽  
Elastic Plastic ◽  
Plastic Shakedown

Elastic-plastic strain distributions at fillet welds

1996 ◽  
Vol 31 (3) ◽  
pp. 215-230 ◽  
Author(s):  
K S Elliott ◽  
H Fessler
Keyword(s):  
Strain Range ◽  
Post Weld Heat Treatment ◽  
Steel Plates ◽  
Plastic Strains ◽  
Weld Toes ◽  
Thick Plates ◽  
Full Size ◽  
Elastic Plastic ◽  
Tensile Forces ◽  
Fringe Patterns

Steel plates 25 mm thick were fillet-welded to 50 mm thick plates according to good offshore welding practice. The thinner plates were inclined at 90° or 60° to the thicker ones to represent, at full size, the crown or saddle positions of a structural tubular T joint. Slices 4 mm or 10 mm thick were cut from these weldments and the elastic, elastic-plastic and residual plastic strains in the surfaces of these sections were measured using photoelastic coatings and moiré interferometry. The slices were loaded by tensile forces on the 25 mm wide parts, reacted at pin joints near the ends of the 50 mm wide part. The positions and directions of loading were arranged to load the welds in the same way as in a tubular T joint, loaded in tension. Yielding initiated at the weld toes and could be clearly identified in the moiré fringe patterns. It progressed into the plates, being inhibited by the heat-affected zone. Maximum plastic strains also occurred at the weld toes. Measurements of residual plastic strains showed that the actual strain range, which ‘drives’ fatigue failure, differs from predictions based on elastic analyses. Post-weld heat treatment is beneficial, but extending the weld along the plate reduces the strain concentrations much more.

An elastic–plastic shakedown analysis of fretting wear

Wear ◽  
2001 ◽  
Vol 247 (1) ◽  
pp. 41-54 ◽  
Author(s):  
S. Fouvry ◽  
Ph. Kapsa ◽  
L. Vincent
Keyword(s):  
Fretting Wear ◽  
Shakedown Analysis ◽  
Elastic Plastic ◽  
Plastic Shakedown

A Direct Analysis of Two-Dimensional Elastic-Plastic Rolling Contact

1993 ◽  
Vol 115 (2) ◽  
pp. 227-236 ◽  
Author(s):  
M. Yu ◽  
B. Moran ◽  
L. M. Keer
Keyword(s):  
Finite Element ◽  
Direct Analysis ◽  
Rolling Contact ◽  
Direct Approach ◽  
Two Dimensional ◽  
Elastic Plastic ◽  
Finite Element Calculations ◽  
Plastic Analysis ◽  
Plastic Shakedown ◽  
Residual Problem

A direct approach for elastic-plastic analysis and shakedown is presented and its application to a two-dimensional rolling contact problem is demonstrated. The direct approach consists of an operator split technique, which transforms the elastic-plastic problem into a purely elastic problem and a residual problem with prescribed eigenstrains. The eigenstrains are determined using an incremental projection method which is valid for nonproportional loading and both elastic and plastic shakedown. The residual problem is solved analytically and also by using a finite element procedure which can be readily generalized to more difficult problems such as three-dimensional rolling point contact. The direct analysis employs linear-kinematic-hardening plastic behavior and thus either elastic or plastic shakedown is assured, however, the phenomenon of ratchetting which can lead to incremental collapse, cannot be treated within the present framework. Results are compared with full elastic-plastic finite element calculations and a step-by-step numerical scheme for elastic-plastic analysis. Good agreement between the methods is observed. Furthermore, the direct method results in substantial savings in computational effort over full elastic-plastic finite element calculations and is shown to be a straightforward and efficient method for obtaining the steady state (shakedown) solution in the analysis of rolling and/or sliding contact.

Development of a Three-Dimensional Semi-Analytical Elastic-Plastic Contact Code

2002 ◽  
Vol 124 (4) ◽  
pp. 653-667 ◽  
Author(s):  
C. Jacq ◽  
D. Ne´lias ◽  
G. Lormand ◽  
D. Girodin
Keyword(s):  
Three Dimensional ◽  
Indentation Test ◽  
Closed Form Expression ◽  
Reciprocal Theorem ◽  
Plastic Strains ◽  
Surface Geometry ◽  
Fe Method ◽  
Elastic Plastic ◽  
Fine Mesh ◽  
The Reciprocal Theorem

A three-dimensional elastic-plastic contact code based on semi-analytical method is presented and validated. The contact is solved within a Hertz framework. The reciprocal theorem with initial strains is then introduced, to express the surface geometry as a function of contact pressure and plastic strains. The irreversible nature of plasticity leads to an incremental formulation of the elastic-plastic contact problem, and an algorithm to solve this problem is set up. Closed form expression, which give residual stresses and surface displacements from plastic strains, are obtained by integration of the reciprocal theorem. The resolution of the elastic-plastic contact using the finite element (FE) method is discussed, and the semi-analytical code presented in this paper is validated by comparing results with experimental data from the nano-indentation test. Finally, the resolution of the rolling elastic-plastic contact is presented for smooth and dented surfaces and for a vertical or rolling loading. The main advantage of this code over classical FE codes is that the calculation time makes the transient analysis of three-dimensional contact problems affordable, including when a fine mesh is required.

Numerical Simulation and Analysis for 3D Elastic-Plastic Rough Contacts

Tribology ◽  
2006 ◽  
Author(s):  
Fan Wang ◽  
Leon M. Keer ◽  
Q. Jane Wang
Keyword(s):  
Real Contact Area ◽  
Plastic Strains ◽  
Normal Contact ◽  
Elastic Plastic ◽  
Hardening Behavior ◽  
Real Contact ◽  
Residual Displacements ◽  
Surface Deflection ◽  
Plastic Hardening ◽  
Contact Field

A 3D elastic-plastic rough contact (EPC) solution and code is developed using a modified semi-analytical method. The total surface deflection is induced by the contact pressure and plastic strain. A purely elastic contact field and a residual field arising from the plastic deformation are simulated iteratively to gain the final approximate solution for the elastic-plastic rough contact. Frictionless normal contact between a rigid ball and an elastic-plastic half space with polished, turned, and honed rough surfaces was numerically simulated using the developed EPC code. The distributions of surface pressures, real contact area, total stresses, residual stresses, residual displacements, and plastic strains are obtained through simulation. The effects of surface roughness, wavelength, and plastic hardening behavior upon the calculated results are analyzed.

A Shell-Element–Based Elastic Analysis Predicting Welding-Induced Distortions for Ship Panels

2007 ◽  
Vol 51 (02) ◽  
pp. 128-136
Author(s):  
Gonghyun Jung
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Shell Element ◽  
Significant Loss ◽  
Buckling Analysis ◽  
Elastic Analysis ◽  
Plastic Strains ◽  
Elastic Plastic ◽  
Distortion Analysis ◽  
Plastic Analysis

A new numerical model, Q-Weld (Edison Welding Institute, Columbus, OH), which is a shell-element-based elastic analysis, is proposed for the prediction of the distortion induced in ship panels. Based on the results of the three-dimensional thermal-elastic-plastic analyses, it was found that the shell element-based model excluding the geometry of fillet welds and including only transverse and longitudinal plastic strains is valid without significant loss of accuracy. The developed Q-Weld predicts well-agreed distortions with the three-dimensional thermal-elastic-plastic analysis and demonstrates its potential in welding-induced distortion analysis, including buckling analysis.

Sign in / Sign up

Export Citation Format

Share Document