VUSUPERELASHARDMOD

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 vusuperelashardmod(
C Read only -
     *     nblock, 
     *     jElem, kIntPt, kLayer, kSecPt, 
     *     stepTime, totalTime, dt, cmname,
     *     nstatev, nfieldv, nprops, 
     *     props, tempOld, tempNew, fieldOld, fieldNew,
     *     stateOld,
     *     CAS, CSA, eqps, RefT, EmodARef,
     *     EnuARef, EmodSRef, EnuSRef, SsASRef, SfASRef, SsSARef,
     *     SfSARef, 
C     Write only (modifiable) variables -
     *     EmodA, EnuA, EmodS, EnuS, SsAS, SfAS, SsSA, SfSA,
     *     stateNew )
C
      include 'vaba_param.inc'
C
      dimension props(nprops), tempOld(nblock), tempNew(nblock),
     1   fieldOld(nblock,nfieldv), fieldNew(nblock,nfieldv),
     2   stateOld(nblock,nstatev), CAS(nblock), CSA(nblock),eqps(nblock),
     3   RefT(nblock), EmodARef(nblock),EnuARef(nblock),EmodSRef(nblock),
     4   EnuSRef(nblock), SsASRef(nblock),SfASRef(nblock),SsSARef(nblock),
     5   SfSARef(nblock),EmodA(nblock),EnuA(nblock),EmodS(nblock),
     4   EnuS(nblock),SsAS(nblock),SfAS(nblock),SsSA(nblock),
     5   SfSA(nblock),stateNew(nblock,nstatev),jElem(nblock)
C
      character*80 cmname
C
      do 100 km = 1,nblock
        user coding
  100 continue
C
      return
      end

Variables to be defined

EmodA(nblock): $E_{A}$ , austenite's Young's modulus.
EnuA(nblock): $ν_{A}$ , austenite's Poisson's ratio.
EmodS(nblock): $E_{M}$ , martensite's Young's modulus.
EnuS(nblock): $ν_{M}$ , martensite's Poisson's ratio.
SsAS(nblock): $σ_{t L}^{S}$ , stress at which the transformation begins during loading in tension.
SfAS(nblock): $σ_{t L}^{E}$ , stress at which the transformation ends during loading in tension.
SsSA(nblock): $σ_{t U}^{S}$ , stress at which the reverse transformation begins during unloading in tension.
SfSA(nblock): $σ_{t U}^{E}$ , stress at which the reverse transformation begins during unloading in tension.
stateNew(nblock,nstatev): Array containing the state variables at the material points at the end of the increment. The allocation of this array is described in Solution-dependent state variables.

Variables passed in for information

nblock: Number of material points.
jElem(nblock): Array of element numbers.
kIntPt: Integration point number.
kLayer: Layer number (for composite shells).
kSecPt: Section point number within the current layer.
stepTime: Value of time since the step began.
totalTime: Value of total time. The time at the beginning of the step is given by totalTime-stepTime.
dt: Time increment size.
cmname: Material name, left-justified. It is passed in as an uppercase character string. Some internal material models are given names starting with the “ABQ_” character string. To avoid conflict, “ABQ_” should not be used as the leading string for cmname.
nstatev: Number of user-defined state variables that are associated with this material type (see Allocating space).
nfieldv: Number of user-defined external field variables.
nprops: User-specified number of user-defined material properties.
tempOld(nblock): Temperatures at the material points at the beginning of the increment.
tempNew(nblock): Temperatures at the material points at the end of the increment.
fieldOld(nblock,nfieldv): Values of the user-defined field variables at the material points at the beginning of the increment.
fieldNew(nblock,nfieldv): Values of the user-defined field variables at the material points at the end of the increment.
stateOld(nblock,nstatev): State variables at the material points at the beginning of the increment.
CAS(nblock): ${(\frac{δ σ}{δ T})}_{L}$ , slope of the stress versus temperature curve for loading.
CSA(nblock): ${(\frac{δ σ}{δ T})}_{U}$ , slope of the stress versus temperature curve for unloading.
eqps(nblock): Equivalent plastic strain at the material points.
RefT(nblock): Reference temperature.
EmodARef(nblock): $E_{A}$ , reference value of austenite's Young's modulus.
EnuARef(nblock): $ν_{A}$ , reference value of austenite's Poisson's ratio.
EmodSRef(nblock): $E_{M}$ , reference value of martensite's Young's modulus.
EnuSRef(nblock): $ν_{M}$ , reference value of martensite's Poisson's ratio.
SsASRef(nblock): $σ_{t L}^{S}$ , reference value of stress at which the transformation begins during loading in tension.
SfASRef(nblock): $σ_{t L}^{E}$ , reference value of stress at which the transformation ends during loading in tension.
SsSARef(nblock): $σ_{t U}^{S}$ , reference value of stress at which the reverse transformation begins during unloading in tension.
SfSARef(nblock): $σ_{t U}^{E}$ , reference value of stress at which the reverse transformation begins during unloading in tension.