DIRECT_KINEMATIC

Description

This object defines a class of kinematic hardening (tensorial back stresses) which can have a more general state variable form, and possibly nonlinear relationship between the integrated strains and the associated stresses. In the gen_evp behavior framework, these models must be used with the following potentials only:

The kinematic models all support static recovery, and possibly have more than a 1-1 relation between the integrated variable size and the kinematic back stress size (forcibly the active tensor size for given problem dimension).

Syntax

The syntax consists of specifying the type of kinematic object, supplying an optional name on the same line, and giving the appropriate coefficient definitions on the following lines. This is summarized below where the keyword specifying a DIRECT_KINEMATIC object is assumed to be *kinematic:

*kinematic type [ name ] \(~\,~\,~\,\) coefficients

Example

A duplication of the classical Armstrong Frederick kinematic class is implemented for verification and testing purposes (Normally using the nonlinear type is the model to choose). An example use of that class is:

*kinematic armstrong_frederick
   C     40000.
   D     500.