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.
Abaqus Elements Guide
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 α11,α22,α33,α12,α13,α23.
User subroutine interface
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
END
Variables to be defined
The
variables described below are element-type dependent.
EQPS
Equivalent plastic strain.
ALPHA(1,1)
First backstress component of the first backstress.
ALPHA(2,1)
Second backstress component of the first backstress.
ALPHA(3,1)
Third backstress component of the first backstress.
Etc.
NTENS backstress component values should be
defined for each backstress.
Variables passed in for information
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
or
Defining rebar as an element property).
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.