
Accession Number : AD0678480
Title : ELASTICPLASTIC WAVES FOR COMBINED STRESSES.
Descriptive Note : Interim technical rept.,
Corporate Author : STANFORD UNIV CALIF DEPT OF APPLIED MECHANICS
Personal Author(s) : Nan,Ning
Report Date : JUL 1968
Pagination or Media Count : 91
Abstract : The general case of plane wave propagation for combined stresses is considered in a halfspace. The analysis is based on an elasticplastic theory for an isotropic workhardening material which satisfies a flow or incremental type law. The stressstrain curve is assumed concave towards the strain axis with possibly a bend at yield. The wave propagation analysis determines the motion to be governed by a system of quasilinear hyperbolic equations of the first order. Two different types of loading are considered in this studythe coupled double shear loading and the combined pressure and shear. The loading functions are continuous and are assumed to be uniformly distributed over the surface for all t. Two distinct wave speeds are found in the plastic region for both loading types. For general loading plastic flow can propagate with each wave speed which may be as fast as the elastic wave speed. This is contrary to wave for a single stress component. This fact may have an important bearing on the interpretation of experiment, for which, in the past, propagation of plastic waves at elastic wave speed has been considered to indicate rate effects. Solutions of the problems are obtained by numerical integration along the characteristics on a step by step basis. The loadingunloading boundaries are determined in the x  t plane. For a simple case of the double shear problem when the components are in proporation, very good agreement is obtained between the numerical result and the known analytical solution. (Author)
Descriptors : (*STRESSES, WAVE PROPAGATION), PLASTIC PROPERTIES, ELASTIC PROPERTIES, NONLINEAR DIFFERENTIAL EQUATIONS, NUMERICAL METHODS AND PROCEDURES, COLD WORKING, STRAIN(MECHANICS), LOAD DISTRIBUTION, PRESSURE, VELOCITY
Subject Categories : Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE