Accession Number : AD0770027

Title :   On the Determination of Constitutive Equations from Plastic Wave Propagation Phenomena.

Descriptive Note : Rept. for Sep 71-Dec 72,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Nicholas,T.

Report Date : SEP 1973

Pagination or Media Count : 34

Abstract : Numerical results of a computer analysis are presented for two problems involving the propagation of plastic waves of uniaxial stress in long rods or bars. Characteristics of the wave propagation phenomena are determined for assumed materials which exhibit strain-rate dependent material behavior of the form proposed by Malvern, using the exponential form of the plastic strain rate function. The results are examined with regard to their uniqueness and sensitivity to the constitutive equation for cases involving the propagation of strain increments in a prestressed rod and for a suddenly applied constant velocity at the end of a long rod. Comparisons are made with predictions of the rate-independent theory of plastic wave propagation using both the static stress-strain curve and a single 'dynamic' curve. The interpretation of experimental results in terms of a proposed constitutive law is discussed.

Descriptors :   (*Plastic properties, Metals), Stress strain relations, Rods, Strain rate, Yield strength

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE