Role of anisotropic strength and stiffness in governing the initiation and propagation of yielding in polycrystalline solids

TL;DR

This paper introduces a strength-to-stiffness parameter for multiaxial loading in polycrystalline solids, enabling prediction of yield initiation based on elastic strain data and crystal properties.

Contribution

It extends previous uniaxial strength-to-stiffness models to multiaxial conditions and develops a finite element yield prediction methodology using elastic data.

Findings

The strength-to-stiffness parameter effectively predicts yield initiation.

Finite element simulations validate the prediction methodology.

The approach enhances understanding of anisotropic yield behavior in polycrystals.

Abstract

The ratio of directional strength-to-stiffness is important in governing the relative order in which individual crystals within a polycrystalline aggregate will yield as the aggregate is loaded. In this paper, a strength-to-stiffness parameter is formulated for multiaxial loading that extends the development of Wong and Dawson for uniaxial loading. Building on the principle of strength-to-stiffness, a methodology for predicting the macroscopic stresses at which elements in a finite element mesh yield is developed. This analysis uses elastic strain data from one increment of a purely elastic finite element simulation to make the prediction, given knowledge of the single-crystal yield surface. Simulations of austenitic strainless steel AL6XN are used to demonstrated the effectivness of the strength-to-stiffness parameter and yield prediction methodology.