ROTSIG (rotate a tensor)

`ROTSIG` (rotate a tensor)

Interface

      CALL ROTSIG(S,R,SPRIME,LSTR,NDI,NSHR)

Variables to be provided to the utility routine

S

A stress or strain tensor.

NDI

Number of direct components.

NSHR

Number of shear components.

R

Rotation matrix.

LSTR

An identifier. LSTR indicates S contains stresses; LSTR indicates S contains strains.

Variable returned from the utility routine

SPRIME

The rotated stress or strain tensor.

Typical usage

In user subroutine UMAT it is often necessary to rotate tensors during a finite-strain analysis. The matrix DROT that is passed into UMAT represents the incremental rotation of the material basis system in which the stress and strain are stored. For an elastic-plastic material that hardens isotropically, the elastic and plastic strain tensors must be rotated to account for the evolution of the material directions. In this case S is the elastic or plastic strain tensor and R is the incremental rotation DROT.