Accession Number : ADA332658

Title :   Continuum Models for Irregular Phase Boundary Motion in Shape-Memory Tensile Bars

Descriptive Note : Technical rept.

Corporate Author : CORNELL UNIV ITHACA NY DEPT OF THEORETICAL AND APPLIED MECHANICS

Personal Author(s) : Rosakis, Phoebus ; Knowles, James K.

PDF Url : ADA332658

Report Date : NOV 1997

Pagination or Media Count : 32

Abstract : We consider quasi-static displacement-control led loading through one stress cycle of a shape-memory tensile bar modeled as a one-dimensional, two-phase elastic solid. Our objective is to explore the effect on the associated hysteresis loop of various qualitatively different types of kinetic relations, bearing in mind certain features of such loops that have been observed experimentally. We show that when the model involves a kinetic relation that is 'unstable' in a definite sense, 'stick-slip' motion of the interface between phases and serration of the accompanying stress-elongation curve are both predicted at slow elongation rates. We also show that a 'nonhomogeneous' kinetic relation intended to model the effect of micro-obstacles on interface motion also leads to irregular interface motion and a serrated stress-elongation curve, in this case at all elongation rates.

Descriptors :   *PHASE TRANSFORMATIONS, *HYSTERESIS, STRESSES, INTERFACES, ELASTIC PROPERTIES, MOTION, BOUNDARIES, KINETICS, LOOPS, TWO PHASE FLOW, ELONGATION, SOLID BODIES, CYCLIC LOADS.

Subject Categories : Physical Chemistry
      Electricity and Magnetism
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE