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Initial stress

User defined initial stress field

This subroutine is used for user-defined initial stresses, characterized by the parameter user on the *initial conditions, type=stress, user command in the input file. The subroutine is called at the start of the analysis for each applicable material calculation point in the model and can be used to define all active initial stress components at material points as functions of coordinates, element number, integration point number, etc.

Linux

subroutine user_initial_stress(ie,igp,ndim,ntens,nchar,material,coords,stress)&
             bind(c,name='user_initial_stress')
  use, intrinsic :: iso_c_binding
  implicit none
  integer(c_int)                  , intent(in)    :: ie         
  integer(c_int)                  , intent(in)    :: igp      
  integer(c_int)                  , intent(in)    :: ndim        
  integer(c_int)                  , intent(in)    :: ntens  
  integer(c_int)                  , intent(in)    :: nchar 
  character(c_char)               , intent(in)    :: material(*) 
  real(c_double), dimension(3)    , intent(in)    :: coords       
  real(c_double), dimension(ntens), intent(inout) :: stress       

  character(len=nchar) :: material_str

  ! required to make the material name usable in select case of if-clauses
  material_str = transfer(material(1:nchar), material_str)

  ... user coding

end subroutine user_initial_stress

Windows

subroutine user_initial_stress(ie,igp,ndim,ntens,nchar,material,coords,stress)
    implicit none
    !DEC$ ATTRIBUTES DLLEXPORT, STDCALL, REFERENCE :: user_initial_stress
  implicit none
  integer                  , intent(in)    :: ie         
  integer                  , intent(in)    :: igp      
  integer                  , intent(in)    :: ndim        
  integer                  , intent(in)    :: ntens  
  integer                  , intent(in)    :: nchar 
  character                , intent(in)    :: material(*) 
  real(8), dimension(3)    , intent(in)    :: coords       
  real(8), dimension(ntens), intent(inout) :: stress       

  character(len=nchar) :: material_str

  ! required to make the material name usable in select case of if-clauses
  material_str = transfer(material(1:nchar), material_str)

  ... user coding

end subroutine user_initial_stress

  • ie: Element label (id)

  • igp: Integration point number in the element

  • ndim: Number of coordinates

  • ntens: Number of stresses to be defined, which depends on the element type.

  • nchar: length of the material name

  • material: Material name assigned to the current element

  • coords(:): Array containing the coordinates of the current integration point

  • stress(:): Array containing the initial stress values to be defined