Accession Number : AD0692475

Title :   CONSTITUTIVE EQUATIONS FOR ELASTIC-PLASTIC MATERIALS AT FINITE STRAIN,

Corporate Author : BROWN UNIV PROVIDENCE R I DIV OF ENGINEERING

Personal Author(s) : Freund,L. B.

Report Date : MAR 1969

Pagination or Media Count : 32

Abstract : Constitutive equations are suggested for describing the behavior of elastic-plastic materials undergoing large strains. A special kinematical viewpoint is taken, so that the elastic and plastic deformation processes can be considered separately. This separation is also accomodated by a simplified thermodynamical theory of the deformation process. The general elastic constitutive equation is written as a rate equation, after examining the interpretation of elastic isotropy in view of the particular kinematical description employed. To describe plastic deformation, a general rate equation, which exhibits no dependence on the rate at which previous states have been traversed, is suggested. After the general relations have been put in appropriate form some simplifications based on physical assumptions are considered. The physical assumptions are based on the behavior of metals under large stress, high speed loading, such as in the penetration problem. Under these operating conditions, the thermoelastic effects dominate and plasticity plays a minor role. Consequently, a simple model of plastic deformation usually suffices. The analysis is presented in direct (matrix) notation and is valid for arbitrary stress states. (Author)

Descriptors :   (*DEFORMATION, EQUATIONS), MATHEMATICAL MODELS, STRAIN(MECHANICS), LOADS(FORCES), STRESSES, ELASTIC PROPERTIES, PLASTIC PROPERTIES, KINEMATICS, THERMODYNAMICS, THERMAL PROPERTIES, ISOTROPISM, PENETRATION, TENSOR ANALYSIS

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE