The parameters of the isotropic hardening model are calibrated by fitting them against the stress-strain curve in the 0° configuration. The procedure depends on the hardening law:
Voce nonlinear isotropic hardening: The parameters
, 
, 
, and 
are the solutions to the least squares minimization
problem
(3–81)
with
defined in Equation 3–71. For
additional information, see the Material Curve-Fitting chapter in the Mechanical APDL
Material Reference.Multilinear isotropic hardening: Stress-plastic strain values are taken from the equivalent stress - equivalent plastic strain curve in the 0° configuration.
Inverse polynomial nonlinear isotropic hardening: The parameters
and 
are determined as solutions of a linear regression
problem [Dillenberger, 2020].
(3–82)