Rate-dependent plasticity: creep and swelling

The classical deviatoric metal creep behavior in Abaqus/Standard:

  • can be defined using user subroutine CREEP or by providing parameters as input for some simple creep laws;

  • can model either isotropic creep (using Mises stress potential) or anisotropic creep (using Hill's anisotropic stress potential);

  • is active only during steps using the coupled temperature-displacement procedure, the transient soils consolidation procedure, and the quasi-static procedure;

  • requires that the material's elasticity be defined as linear elastic behavior;

  • can be modified to implement the auxiliary creep hardening rules specified in Nuclear Standard NEF 9-5T, “Guidelines and Procedures for Design of Class 1 Elevated Temperature Nuclear System Components”; these rules are exercised by means of a constitutive model developed by Oak Ridge National Laboratory (ORNL – Oak Ridge National Laboratory constitutive model);

  • can be used in combination with creep strain rate control in analyses in which the creep strain rate must be kept within a certain range; and

  • can potentially result in errors in calculated creep strains if anisotropic creep and plasticity occur simultaneously (discussed below).

Rate-dependent gasket behavior in Abaqus/Standard:

  • uses unidirectional creep as part of the model of the gasket's thickness-direction behavior;

  • can be defined using user subroutine CREEP or by providing parameters as input for some simple creep laws;

  • is active only during steps using the quasi-static procedure; and

  • requires that an elastic-plastic model be used to define the rate-independent part of the thickness-direction behavior of the gasket.

Volumetric swelling behavior in Abaqus/Standard:

  • can be defined using user subroutine CREEP or by providing tabular input;

  • can be either isotropic or anisotropic;

  • is active only during steps using the coupled temperature-displacement procedure, the transient soils consolidation procedure, and the quasi-static procedure; and

  • requires that the material's elasticity be defined as linear elastic behavior.

The following topics are discussed:

Related Topics
About the material library
Inelastic behavior
In Other Guides
Defining the gasket behavior directly using a gasket behavior model
*CREEP
*CREEP STRAIN RATE CONTROL
*POTENTIAL
*SWELLING
*RATIOS
Defining a creep law
Defining swelling

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