Difference between revisions of "Nonlinear Hardening 1"

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! Property !! Description  
! Property !! Description  
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| yield ||  The initial yield stress (enter in units of MPa). This stress corresponds to the axial stress at yield during uniaxial, 3D loading.
| yield ||  The initial yield stress (enter in [[ConsistentUnits Command#Legacy and Consistent Units|pressure units]]). This stress corresponds to the axial stress at yield during uniaxial, 3D loading.
|-
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| Khard || The dimensionless parameter K for nonlinear hardening.
| Khard || The dimensionless parameter K for nonlinear hardening.

Revision as of 14:54, 2 June 2015

In this nonlinear hardening law, the yield stress is given by

      [math]\displaystyle{ \sigma_y = \sigma_{Y0}(1+K\alpha)^n }[/math]

where [math]\displaystyle{ \sigma_{Y0} }[/math] is initial yield stress, α is cumulative equivalent plastic strain, and K and n are dimensionless hardening law coefficients.

An alternate nonlinear hardening law is also available.

Hardening Law Properties

The material parameters in this hardening law are defined with the following properties:

Property Description
yield The initial yield stress (enter in pressure units). This stress corresponds to the axial stress at yield during uniaxial, 3D loading.
Khard The dimensionless parameter K for nonlinear hardening.
nhard The dimensionless exponent parameter (n) in the nonlinear hardening law. If n=1, it is more efficient to use linear hardening instead.

History Data

This hardening law defines one history variable, which is stored as history variable #1. It stores the the cumulative equivalent plastic strain (absolute) defined as

      [math]\displaystyle{ \alpha = \sum \sqrt{2\over3}\ ||d\varepsilon_p|| }[/math]

where dεp is the incremental plastic strain tensor in one time step.