*PLASTIC

Optional parameters

HARDENING

Set HARDENING=ISOTROPIC (default) to specify isotropic hardening.

Set HARDENING=KINEMATIC to specify linear kinematic hardening.

Set HARDENING=MULTILINEAR KINEMATIC to specify multilinear kinematic hardening.

Set HARDENING=COMBINED to specify nonlinear isotropic/kinematic hardening.

Set HARDENING=JOHNSON COOK to specify Johnson-Cook hardening.

Set HARDENING=USER to define isotropic hardening in user subroutine UHARD in an Abaqus/Standard analysis or user subroutine VUHARD in an Abaqus/Explicit analysis.

SCALESTRESS

This parameter cannot be used with the HARDENING parameter.

Set this parameter equal to the factor by which you want the yield stress to be scaled.

Optional parameter for use with HARDENING=ISOTROPIC or HARDENING=COMBINED

DEPENDENCIES: Set this parameter equal to the number of field variable dependencies included in the definition of hardening behavior, in addition to temperature and possibly strain range. If this parameter is omitted, the hardening behavior does not depend on field variables. See Material Data Definition for more information.

Optional parameters for use with HARDENING=ISOTROPIC

EXTRAPOLATION

This parameter specifies the extrapolation method for the yield stress with respect to the equivalent plastic strain.

If you use the PLASTIC option multiple times to specify test data at different equivalent plastic strain rates, you can use the EXTRAPOLATION parameter only one time, when you specify data at a zero equivalent plastic strain rate (PLASTIC, RATE=0.0). On the subsequent options, you must either omit the EXTRAPOLATION parameter or specify the same method as that used at a zero equivalent plastic strain rate.

Set EXTRAPOLATION=CONSTANT (default) to use a constant value of the yield stress outside the specified range of the equivalent plastic strains.

Set EXTRAPOLATION=LINEAR to use linear extrapolation (based on the slope) of the yield stress outside the specified range of the equivalent plastic strains.

RATE

Set this parameter equal to the equivalent plastic strain rate, ${\dot{\bar{ε}}}^{p l}$ , for which this stress-strain curve applies.

Optional parameters for use with HARDENING=COMBINED

DATA TYPE

Set DATA TYPE=HALF CYCLE (default) to specify stress versus plastic strain values of the first half-cycle for calibrating the kinematic hardening parameters.

Set DATA TYPE=PARAMETERS to specify the calibrated kinematic hardening material parameters directly.

Set DATA TYPE=STABILIZED to specify stress versus plastic strain values of a stabilized cycle for calibrating the kinematic hardening parameters.

NUMBER BACKSTRESSES

Set this parameter equal to the number of backstresses. The default number of backstresses is 1, and the maximum allowed is 10.

STATIC RECOVERY

This parameter can be used only in conjunction with DATA TYPE=PARAMETERS.

Include this parameter to indicate that the static recovery term must be included with the nonlinear isotropic/kinematic hardening model.

Optional parameter for use with HARDENING=USER

PROPERTIES: Set this parameter equal to the number of property values needed as data in user subroutine UHARD in Abaqus/Standard analyses and user subroutine VUHARD in Abaqus/Explicit analyses. The default is PROPERTIES=0.

Data lines for HARDENING=ISOTROPIC or HARDENING=COMBINED with DATA TYPE=HALF CYCLE

First line

Yield stress.
Plastic strain.
Temperature.
First field variable.
Second field variable.
Etc., up to five field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than five)

Sixth field variable.
Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the dependence of yield stress on plastic strain and, if needed, on temperature and other predefined field variables.

Data lines for HARDENING=COMBINED with DATA TYPE=STABILIZED

First line

Yield stress.
Plastic strain.
Strain range.
Temperature.
First field variable.
Second field variable.
Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four)

Fifth field variable.
Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the dependence of yield stress on plastic strain and, if needed, on strain range, temperature, and other predefined field variables.

Data lines for HARDENING=COMBINED with DATA TYPE=PARAMETERS

First line

Yield stress at zero plastic strain.
Kinematic hardening parameter, $C_{1}$ .
Kinematic hardening parameter, $γ_{1}$ .
Etc., specify kinematic hardening parameters $C_{k}$ and $γ_{k}$ for each backstress k. (Only needed if the NUMBER BACKSTRESSES parameter has a value greater than 1.)
Temperature.
First field variable.
Second field variable.
Etc., up to eight entries per line.

Subsequent lines (only needed if the number of entries is greater than eight)

Etc., up to eight entries per line.

Repeat this set of data lines as often as necessary to define the dependence of yield stress and kinematic hardening parameters $C_{k}$ and $γ_{k}$ on temperature and other predefined field variables.

Data lines for HARDENING=COMBINED with DATA TYPE=PARAMETERS and STATIC RECOVERY

First line

Yield stress at zero plastic strain.
Kinematic hardening parameter, $C_{1}$ . (Units of FL⁻².)
Kinematic hardening parameter, $γ_{1}$ .
Kinematic hardening parameter, $ξ_{1}$ . (Units of T⁻¹.)
Kinematic hardening parameter, ${\bar{R}}_{1}$ . (Units of FL⁻².)
Kinematic hardening parameter, $m_{1}$ .
Etc., specify kinematic hardening parameters $C_{k}$ , $γ_{k}$ , $ξ_{k}$ , ${\bar{R}}_{k}$ , and $m_{k}$ for each backstress k. (Only needed if the NUMBER BACKSTRESSES parameter has a value greater than 1.)
Temperature.

Subsequent lines (only needed if the number of entries is greater than eight)

First field variable.
Second field variable.
Etc., up to eight entries per line.

Repeat this set of data lines as often as necessary to define the dependence of yield stress and kinematic hardening parameters on temperature and other predefined field variables.

Data lines for HARDENING=KINEMATIC

First line

Yield stress.
Plastic strain.
Temperature, if temperature dependent.

Repeat this data line a maximum of two times to define linear kinematic hardening independent of temperature. Repeat this set of data lines as often as necessary to define a variation of the linear kinematic hardening modulus with respect to temperature.

Data lines for HARDENING=MULTILINEAR KINEMATIC

First line

Yield stress.
Plastic strain.
Temperature, if temperature dependent.
First field variable.
Second field variable.
Etc., up to eight entries per line.

Subsequent lines (only needed if the number of entries is greater than eight)

Etc., up to eight entries per line.

Repeat this set of data lines as often as necessary to define the dependence of yield stress on plastic strain and, if needed, on temperature and other predefined field variables.

Data line for HARDENING=JOHNSON COOK

First (and only) line

A. (Units of FL⁻².)
B. (Units of FL⁻².)
n. (Dimensionless.)
m. (Dimensionless.) If this field is left blank or a zero value is specified, the yield stress does not depend on temperature.
Melting temperature, $θ_{melt}$ . (Only required if a nonzero value of m is specified.)
Transition temperature, $θ_{transition}$ . (Only required if a nonzero value of m is specified.)

Data lines for HARDENING=USER with PROPERTIES

First line

Give the hardening properties, eight per line.

Repeat this data line as often as necessary to define all hardening properties.