Finite-Element-Based Multiple Normal Loading-Unloading of an Elastic-Plastic Spherical Stick Contact

Biplab Chatterjee,Prasanta Sahoo

doi:10.5402/2013/871634

Abstract

The repeated normal elastic plastic contact problem of a deformable sphere against a rigid flat under full stick contact condition is investigated with a commercial finite element software ANSYS. Emphasis is placed on the effect of strain hardening and hardening model with the maximum interference of load ranging from elastic to fully plastic, which has not yet been reported. Different values of tangent modulus coupled with isotropic and kinematic hardening models are considered to study their influence on contact parameters. Up to ten normal loading-unloading cycles are applied with a maximum interference of 200 times the interference required to initiate yielding. Results for the variation of mean contact pressure, contact load, residual interference, and contact area with the increasing number of loading unloading cycles at high hardening parameter as well as for low tangent modulus with two different hardening models are presented. Results are compared with available finite element simulations and in situ results reported in the literature. It is found that small variation of tangent modulus results in same shakedown behavior and similar interfacial parameters in repeated loading-unloading with both the hardening rules. However at high tangent modulus, the strain hardening and hardening rules have strong influence on contact parameters.

Highlights

Multiple repeated normal loading unloading is common in engineering applications
Johnson [26] mentioned that the surface tractions and nonlinear material properties are the factors to in uence the reversibility of cyclic normal loading in spherical contact problems. us under a speci c contact condition, the plastic properties of the material and the hardening rule have a particular importance in multiple normal loadingunloading. ough under perfect slip contact condition the effect of strain hardening on loading unloading of a deformable sphere against a rigid at is available in literature, the effect of plastic properties and hardening model for multiple normal loading-unloading for a deformable spherical contact under full stick contact condition is still missing
Strain hardening is expressed in terms of tangent modulus (EEtt), which is the slope of the stress-strain curve

Summary

Introduction

Multiple repeated normal loading unloading is common in engineering applications. Several researchers have identi ed the use of repeated normal loading unloading in various elds of engineering applications such as contact resistance in MEMS micro switches [1, 2], head-disk interaction in magnetic storage systems [3], ultrasonic interfacial stiffness measurement [4], stamping mechanism, and in rolling element bearings, gears, cams, and so forth. Chatterjee and Sahoo [25] studied the effect of strain hardening on the elastic plastic contact loading of a deformable sphere against a rigid at under full stick contact condition with two different hardening rules. Ough under perfect slip (frictionless) contact condition the effect of strain hardening on loading unloading of a deformable sphere against a rigid at is available in literature, the effect of plastic properties and hardening model for multiple normal loading-unloading for a deformable spherical contact under full stick contact condition is still missing. E present investigation aims at studying the effect of strain hardening and hardening models on contact parameters during multiple normal loading-unloading of a deformable sphere against a rigid at under full stick contact condition using commercial nite element so ware ANS S

Theoretical Background

Finite Element Model

Results and Discussion

Elements

Conclusion