Accessing Abaqus thermal materials

Utility routine MATERIAL_LIB_HT returns heat fluxes, internal energy time derivative, volumetric heat generation rate, and their derivatives at the element material point.

The routine can be called only from Abaqus/Standard user subroutine UELMAT.

The following topics are discussed:

Utility routine interface
Variables to be provided to the utility routine
Variables returned from the utility routine

Utility routine interface

     dimension predef(npredef),dpredef(npredef),dtemdx(*),
    *         rhodUdg(*),flux(*),dfdt(*),dfdg(ndim,*),drpldt(*),    *         coords(3)
     ...

     call material_lib_ht(materiallib,rhoUdot,rhodUdt,rhodUdg,
    *       flux,dfdt,dfdg,rpl,drpldt,npt,dvmat,predef,
    *       dpredef,npredf,temp,dtemp,dtemdx,celent,coords)
     ...

Variables to be provided to the utility routine

materiallib: Variable containing information about the Abaqus material. This variable is passed into user subroutine UELMAT.
npt: Integration point number.
dvmat: Volume at the integration point.
predef: Array of interpolated values of predefined field variables at the integration point at the start of the increment.
dpredef: Array of increments of predefined field variables.
npredf: Number of predefined field variables, including temperature.
temp: Temperature at the integration point at the start of the increment, $θ$ .
dtemp: Increment of temperature.
dtemdx: Spatial gradients of temperature, $\partial θ / \partial x$ , at the end of the increment.
celent: Characteristic element length.
coords: The array containing the original coordinates of this point.

Variables returned from the utility routine

rhoUdot: Time derivative of the internal thermal energy per unit mass, U, multiplied by density at the end of increment.
rhodUdt: Variation of internal thermal energy per unit mass with respect to temperature multiplied by density evaluated at the end of the increment.
rhodUdg: Variation of internal thermal energy per unit mass with respect to the spatial gradients of temperature, $\partial U / \partial (\partial θ / \partial x)$ , multiplied by density at the end of the increment.
flux: Heat flux vector, $f$ , at the end of the increment.
dfdt: Variation of the heat flux vector with respect to temperature, $\partial f / \partial θ$ , evaluated at the end of the increment.
dfdg: Variation of the heat flux vector with respect to the spatial gradients of temperature, $\partial f / \partial (\partial θ / \partial x)$ , at the end of the increment
rpl: Volumetric heat generation per unit time at the end of the increment.
drpldt: Variation of rpl with respect to temperature.