Accession Number : AD0669695

Title :   SOME MECHANICAL AND THERMODYNAMICAL ASPECTS OF PLASTICITY,

Corporate Author : BROWN UNIV PROVIDENCE R I DIV OF ENGINEERING

Personal Author(s) : Rice,James R.

Report Date : APR 1966

Pagination or Media Count : 57

Abstract : Some mechanical and thermodynamical results pertaining to the behavior of a macroscopic sample of elastic-plastic material are given, as based on assumptions which idealize certain salient features of plastic flow. At the macroscopic level, a limited range of linear reversible mechanical behavior is assumed to exist with history independent properties relating variations of forces, displacements, and temperature. It is shown that the internal energy and entropy then split additively into macro- and micro-parts, the latter locked into the sample by irreversible deformation and constant during reversible deformation, and the former given by the usual elastic expressions. The second law restriction, for time-independent or dependent behavior, is that macroscopic plastic work must exceed the change in 'locked-in' energy. Modeling plastic flow on a microscopic level as elastic behavior accompanied by material rearrangement through microstructural deformation, in the form of slip on a sufficiently small scale, quantities pertaining to irreversibility such as macroscopic plastic displacements, plastic work, micro-energy, and micro-entropy are evaluated as the works of appropriate forces on the microstructural deformation field. Micro-entropy is found to vanish for material samples exhibiting homogeneous thermal expansion. (Author)

Descriptors :   (*PLASTIC PROPERTIES, MICROSTRUCTURE), MECHANICAL PROPERTIES, THERMODYNAMICS, CREEP, IRREVERSIBLE PROCESSES, DEFORMATION, THERMAL EXPANSION, FREE ENERGY

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE