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Title:The mechanics of shear-band formation in thermal viscoplastic materials at high rates of loading
Author(s):Sherif, Raed A.
Doctoral Committee Chair(s):Shawki, Tarek G.
Department / Program:Applied Mechanics
Discipline:Applied Mechanics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Applied Mechanics
Abstract:The mechanics of adiabatic shear bands are investigated through the study of a one-dimensional simple shearing model. The materials considered are assumed to exhibit strain rate hardening, thermal softening, and strain hardening or softening. The mechanism leading to shear band formation is assumed to be a thermo-mechanical mechanism.
First, we identify the different stages associated with the localization of plastic flow. The limits of validity of the thermo-mechanical mechanism are then discussed. We investigate the existence and uniqueness of a homogeneous, spatially independent solution to the problem. Accordingly, we present a distinction between the notions of shear instability and shear localization. Necessary and sufficient conditions for shear instability are derived. We investigate the necessary and sufficient conditions for the homogeneous deformation to localize through the use of a linear stability theory. The analysis is supported by numerical solutions to the nonlinear system of governing equations. We then investigate the behavior of the field variables at the late stages of deformation. We present an exact steady state formulation for the nonlinear problem. Exact and asymptotic solutions are obtained for the steady state problem.
Issue Date:1989
Type:Text
Language:English
URI:http://hdl.handle.net/2142/23509
Rights Information:Copyright 1989 Sherif, Raed A.
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9011018
OCLC Identifier:(UMI)AAI9011018


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