4.4.3 User-supplied

For the user-supplied hyperelasticity model you must specify two sets of input data: for the deviatoric and for the hydrostatic strain energy functions. DIANA will pass the data to the user-supplied subroutine USRRUB [§11.1.3].

Deviatoric strain energy    (syntax)

RUBBER USER

indicates that the deviatoric strain energy function is defined via a user-supplied Fortran subroutine [§11.1.3].

RUBMOD

keyword usrkey is passed to argument usrkey of the user-supplied subroutine.

RUBVAL

rubval is a series of rubber parameters. These parameters cannot be modified in the subroutine.

USRSTA

usrsta are the initial values of a series of internal state variables. These variables may be used and modified in the subroutine.

USRIND

usrind are the initial values of a series of integer indicator variables. These variables may be used and modified in the subroutine.

    (file.dat)

'MATERI'
    1  RUBBER   USER
       RUBMOD   MYMODL
       RUBVAL   1.0
       USRSTA   0.0
       USRIND   0 0

Hydrostatic strain energy    (syntax)

COMPRE USER

indicates that the hydrostatic strain energy function is defined via a user-supplied Fortran subroutine [§11.1.3].

BULK

k is the bulk modulus $\kappa$ . ( $\kappa$ $\geq$ 0 ) [ $\kappa$ = 10⁶ ] This parameter is applied to setup the linear elastic stiffness, it is not used in the subroutine.

COMVAL

comval is a series of initial compressibility parameters. These parameters cannot be modified in the subroutine.

    (file.dat)

'MATERI'
    1  COMPRE   USER
       BULK     1000.
       COMVAL   1.0 2.0