Fortran User Subroutine (UMAT) for Abaqus.

This dataset contains the Fortran code for the user subroutine (UMAT) used in the article "A thermo-elasto-viscoplastic model for polymers" (https://doi.org/10.1016/j.jmps.2018.11.018) by Joakim Johnsen, Arild Holm Clausen, Frode Grytten, Ahmed Benallal and Odd Sture Hopperstad.

The dataset also includes an example input file for a thermomechanical axisymmetric uniaxial tensile test built for Abaqus 6.14-4. Note that you need to link Abaqus to a Fortran compiler in order to run the model with the user subroutine.

The following properties must be given in the material card:

-- PART A PROPERTIES
PROPS(1) : Initial shear modulus Part A
PROPS(2) : Temperature sensitivity of shear modulus in Part A
PROPS(3) : Activation enthalpy for alpha relaxation
PROPS(4) : Activation volume for alpha relaxation
PROPS(5) : Reference plastic strain rate for alpha relaxation (give as natural logarithm value)
PROPS(6) : Parameter governing evolution of reference plastic strain rate for alpha relaxation
PROPS(7) : Activation enthalpy for beta relaxation
PROPS(8) : Activation volume for beta relaxation
PROPS(9) : Reference plastic strain rate for beta relaxation (give as natural logarithm value)
PROPS(10) : Parameter governing evolution of reference plastic strain rate for beta relaxation
PROPS(11) : Boltzmann's constant
PROPS(12) : Universal gas constant
PROPS(13) : Reference temperature
PROPS(14) : Tolerance used in convergence criterion
PROPS(15) : Maximum number of iterations in the semi-implicit integration

-- PART B PROPERTIES
PROPS(16) : Initial shear modulus Part B
PROPS(17) : Bulk modulus
PROPS(18) : Locking stretch
PROPS(19) : Thermal expansion coefficient

--- COMMON PROPERTIES
PROPS(20) : Density
PROPS(21) : Specific heat capacity
PROPS(22) : Factor controlling substepping