A finite element analysis of residual stress at the unloaded stage of the indentation of an elastic-work hardening layered half-space by a rigid sphere

Using the Finite Element Method, an analysis is given of the indentation of an elasticplastic half-space by a rigid sphere. In particular, attention is focused on the effect of hardening rules on the material response. The materials considered are supposed to exhibit isotropic and kinematic hardening. Moreover, it is shown that the possibility of similar behavior due to effects of friction can be ruled out.

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Finite Element Analysis of Repeated Indentation of an Elastic-Plastic Layered Medium by a Rigid Sphere, Part I: Surface Results

Journal of Applied Mechanics ◽

10.1115/1.2895880 ◽

1995 ◽

Vol 62 (1) ◽

pp. 20-28 ◽

Cited By ~ 54

Author(s):

E. R. Kral ◽

K. Komvopoulos ◽

D. B. Bogy

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Half Space ◽

Contact Pressure ◽

Peak Load ◽

Rigid Sphere ◽

Element Analysis ◽

Elastic Plastic ◽

Surface Stresses ◽

Residual Displacements

A comprehensive elastic-plastic finite element analysis is presented for the axisym-metric problem of a frictionless rigid sphere indenting a half-space with a harder and stiffer layer. The indenter is modeled by contact elements, thereby avoiding a priori assumptions for the pressure profile. Two layer thicknesses are examined, with layer elastic modulus and yield stress both two and four times greater than those of the substrate. Perfectly plastic and isotropic strain-hardening behavior of the layer and substrate media are investigated. At least three complete load-unload cycles are applied to a peak load of 300 times the load necessary to initiate yielding in a half-space of the substrate material. The effect of hardening properties on the loaded and residual stresses is presented and the consequences for crack initiation at the surface are discussed. Results for the contact pressure and surface stresses and deformations are presented, and the influence of residual displacements and load cycles on the contact pressure and the loaded and residual surface stresses is investigated.

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Finite Element Analysis of the Rolling Contact Fatigue Life of Railcar Wheels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.575-578.1461 ◽

2008 ◽

Vol 575-578 ◽

pp. 1461-1466

Author(s):

Byeong Choon Goo ◽

Jung Won Seo

Keyword(s):

Heat Treatment ◽

Residual Stress ◽

Finite Element Analysis ◽

Finite Element ◽

Fatigue Life ◽

Contact Fatigue ◽

Rolling Contact ◽

Element Analysis ◽

Railway Vehicles ◽

Contact Fatigue Life

Railcar wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles have been more severe in recent years due to speed-up. Therefore, a more precise evaluation of railcar wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railcar wheel failure. One of the main sources influencing on the contact zone failure is residual stress. The residual stress in wheels formed during heat treatment in manufacturing changes in the process of braking. Thus the fatigue life of railcar wheels should be estimated by considering both thermal stress and rolling contact. Also, the effect of residual stress variation due to manufacturing process and braking process should be included in simulating contact fatigue behavior. In this paper, an evaluation procedure for the contact fatigue life of railcar wheels considering the effects of residual stresses due to heat treatment, braking and repeated contact load is proposed. And the cyclic stressstrain history for fatigue analysis is simulated by finite element analysis for the moving contact load.

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