2.1.12 Obtaining principal stress/strain values and directions in an Abaqus/Explicit analysis

Product: Abaqus/Explicit

Reference

“VUMAT,” Section 1.2.17

Overview

For Abaqus/Explicit user subroutines that store stress and strain components according to the convention presented in “Conventions,” Section 1.2.2 of the Abaqus Analysis User's Manual, a number of utility routines are available for calculating principal stress/strain values and principal stress/strain directions from the relevant tensors. These routines are most commonly called from user subroutine VUMAT.

The following utility subroutines are available in Abaqus/Explicit to perform tensor operations:

VSPRINC (calculate principal values)
VSPRIND (calculate principal values and directions)

These utility subroutines are described below.

`VSPRINC` (calculate principal values)

Interface

      call vsprinc( nblock, s, eigVal, ndir, nshr )

Variables to be provided to the utility routine

s(nblock,ndir+nshr)

Stress or strain symmetric tensor.

nblock

Number of material points to be processed in this call to VSPRINC.

ndir

Number of direct components in the symmetric tensor.

nshr

Number of shear components in the symmetric tensor.

Variable returned from the utility routine

eigVal(nblock,I), I=1,2,3

The three principal values.

`VSPRIND` (calculate principal values and directions)