USUPERELASHARDMOD

User subroutine to modify the material constants of the superelasticity model as a function of the plastic strain.

is called at all material calculation points of elements for which the material definition includes user-defined hardening modifications; and
can use field variables or state variables.

The following topics are discussed:

User subroutine interface
Variables to be defined
Variables passed in for information

User subroutine interface

      SUBROUTINE USUPERELASHARDMOD(CMNAME,EQPLAS,
     1     NOEL,NPT,LAYER,KSPT,KINC,KSTEP,NSTATV,TEMP,DTEMP,REFT,
     2     TIME,DTIME,PROPS,NUMPROPS,NUMFIELDV,PREDEF,DPRED,
     3     EMODAREF,ENUAREF,EMODSREF,ENUSREF,SSASREF,SFASREF,SSSAREF,SFSAREF,
     4     CAS,CSA,EMODA,ENUA,EMODS,ENUS,SSAS,SFAS,SSSA,SFSA,STATEV)
C
      INCLUDE 'ABA_PARAM.INC'
C
      CHARACTER*80 CMNAME
      DIMENSION STATEV(NSTATV),TIME(*),
     $          PREDEF(NUMFIELDV),DPRED(NUMFIELDV),PROPS(NUMPROPS)

      user coding to define EMODA,ENUA,EMODS,ENUS,SSAS,SFAS,SSSA,SFSA

      RETURN
      END

Variables to be defined

EMODA: $E_{A}$ , austenite's Young's modulus.
ENUA: $ν_{A}$ , austenite's Poisson's ratio.
EMODS: $E_{M}$ , martensite's Young's modulus.
ENUS: $ν_{M}$ , martensite's Poisson's ratio.
SSAS: $σ_{t L}^{S}$ , stress at which the transformation begins during loading in tension.
SFAS: $σ_{t L}^{E}$ , stress at which the transformation ends during loading in tension.
SSSA: $σ_{t U}^{S}$ , stress at which the reverse transformation begins during unloading in tension.
SFSA: $σ_{t U}^{E}$ , stress at which the reverse transformation begins during unloading in tension.
STATEV(NSTATV): Array containing the user-defined, solution-dependent state variables at this point. These are supplied as values at the beginning of the increment or as values updated by other user subroutines (see About user subroutines and utilities) and must be returned as values at the end of the increment.

Variables passed in for information

CMNAME: User-specified material name, left-justified.
EQPLAS: Equivalent plastic strain, ${\bar{ε}}^{p l} .$
NOEL: Element number.
NPT: Integration point number.
LAYER: Layer number (for composite shells and layered solids).
KSPT: Section point number within the current layer.
KINC: Increment number.
KSTEP: Step number.
NSTATV: User-specified number of solution-dependent state variables associated with this material (Allocating space).
TEMP: Temperature at the beginning of the increment.
DTEMP: Increment of temperature.
REFT: Reference temperature.
TIME(1): Value of step time at the beginning of the current increment.
TIME(2): Value of total time at the beginning of the current increment.
DTIME: Time increment.
NPROPS: Number of hardening properties entered for this user-defined hardening definition.
PROPS(NPROPS): Array of hardening properties entered for this user-defined hardening definition.
NUMFIELDV: Number of field variables.
PREDEF(NUMFIELDV): Array of interpolated values of predefined field variables at this material point at the start of the increment based on the values read in at the nodes (initial values at the beginning of the analysis and current values during the analysis).
DPRED(NUMFIELDV): Array of increments of predefined field variables at this material point for this increment, which includes any values updated by user subroutine USDFLD.
CAS: ${(\frac{δ σ}{δ T})}_{L}$ , slope of the stress versus temperature curve for loading.
CSA: ${(\frac{δ σ}{δ T})}_{U}$ , slope of the stress versus temperature curve for unloading.
EMODAREF: $E_{A}$ , reference value of austenite's Young's modulus.
ENUAREF: $ν_{A}$ , reference value of austenite's Poisson's ratio.
EMODSREF: $E_{M}$ , reference value of martensite's Young's modulus.
ENUSREF: $ν_{M}$ , reference value of martensite's Poisson's ratio.
SSASREF: $σ_{t L}^{S}$ , reference value of stress at which the transformation begins during loading in tension.
SFASREF: $σ_{t L}^{E}$ , reference value of stress at which the transformation ends during loading in tension.
SSSAREF: $σ_{t U}^{S}$ , reference value of stress at which the reverse transformation begins during unloading in tension.
SFSAREF: $σ_{t U}^{E}$ , reference value of stress at which the reverse transformation begins during unloading in tension.