Product: ABAQUS/Standard
“Initial conditions,” Section 27.2.1 of the ABAQUS Analysis User's Manual
“Classical metal plasticity,” Section 18.2.1 of the ABAQUS Analysis User's Manual
“Models for metals subjected to cyclic loading,” Section 18.2.2 of the ABAQUS Analysis User's Manual
“Extended Drucker-Prager models,” Section 18.3.1 of the ABAQUS Analysis User's Manual
User subroutine HARDINI:
can be used only for material models that use metal plasticity or Drucker-Prager plasticity;
can be used to provide initial equivalent plastic strain values as a function of element number, material point number, and/or material point coordinates for isotropic and combined hardening;
enables you to specify initial conditions for the backstress tensor as a function of element number, material point number, and/or material point coordinates for kinematic and combined hardening;
will be called to define the initial equivalent plastic strain and, if relevant, the initial backstresses at material points for which user-subroutine-defined initial hardening conditions are specified; and
is intended for use when the initial equivalent plastic strain and/or backstress distributions are too complicated to specify directly as initial hardening conditions.
The number of backstress components that must be defined depends on the element type for which this routine is being called. Part VI, “Elements,” of the ABAQUS Analysis User's Manual describes the number of stress components for each element type; the number of backstress components is identical to the number of stress components. The order of the backstress components is the same as the order of the stress components. For example, in three-dimensional continuum elements six backstress components must be defined in the order 
SUBROUTINE HARDINI(ALPHA,EQPS,COORDS,NTENS,NCRDS,NOEL,NPT,
1 LAYER,KSPT,LREBAR,REBARN)
C
INCLUDE 'ABA_PARAM.INC'
C
DIMENSION ALPHA(NTENS),COORDS(NCRDS)
CHARACTER*80 REBARN
user coding to define EQPS and, if relevant, ALPHA(NTENS)
RETURN
ENDThe variables described below are element-type dependent.
EQPS
Equivalent plastic strain.
ALPHA(1)
First backstress component.
ALPHA(2)
Second backstress component.
ALPHA(3)
Third backstress component.
Etc.
NTENS backstress values should be defined.
COORDS
An array containing the initial coordinates of this point.
NTENS
Number of backstress values to be defined. This number depends on the element type.
NCRDS
Number of coordinates.
NOEL
Element number.
NPT
Integration point number.
LAYER
Layer number (for composite shells and layered solids).
KSPT
Section point number within the current layer.
LREBAR
Rebar flag. If LREBAR=1, the current integration point is associated with element rebar. Otherwise, LREBAR=0.
REBARN
Name of the rebar to which the current integration point belongs, which is the name given in the rebar or rebar layer definition (“Defining reinforcement,” Section 2.2.3 of the ABAQUS Analysis User's Manual, or “Defining rebar as an element property,” Section 2.2.4 of the ABAQUS Analysis User's Manual). If no name was given in the rebar or rebar layer definition, this variable will be blank. This variable is relevant only when LREBAR=1.