modsti.F

Go to the documentation of this file.

Copyright>        OpenRadioss
Copyright>        Copyright (C) 1986-2025 Altair Engineering Inc.
Copyright>
Copyright>        This program is free software: you can redistribute it and/or modify
Copyright>        it under the terms of the GNU Affero General Public License as published by
Copyright>        the Free Software Foundation, either version 3 of the License, or
Copyright>        (at your option) any later version.
Copyright>
Copyright>        This program is distributed in the hope that it will be useful,
Copyright>        but WITHOUT ANY WARRANTY; without even the implied warranty of
Copyright>        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Copyright>        GNU Affero General Public License for more details.
Copyright>
Copyright>        You should have received a copy of the GNU Affero General Public License
Copyright>        along with this program.  If not, see <https://www.gnu.org/licenses/>.
Copyright>
Copyright>
Copyright>        Commercial Alternative: Altair Radioss Software
Copyright>
Copyright>        As an alternative to this open-source version, Altair also offers Altair Radioss
Copyright>        software under a commercial license.  Contact Altair to discuss further if the
Copyright>        commercial version may interest you: https://www.altair.com/radioss/.
!||====================================================================
!||    modsti   ../engine/source/time_step/modsti.F
!||--- called by ------------------------------------------------------
!||    resol    ../engine/source/engine/resol.F
!||====================================================================
      SUBROUTINE modsti(NODFT,NODLT,STIFN,VISCN,MS)
C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------
C   C o m m o n   B l o c k s
C-----------------------------------------------
C
      INTEGER NODFT,NODLT
      my_real 
     .  stifn(*),viscn(*),ms(*)
C----------------------------------------
C   L o c a l   V a r i a b l e s
C----------------------------------------
      INTEGER I,N
      my_real 
     .  c2,c21,aux
C----------------------------------------
       DO i=nodft,nodlt
        IF(ms(i)>zero)THEN
         c2      = four*viscn(i)*viscn(i)
         c21     = eight*ms(i)*stifn(i)
         aux     = sqrt(c2+c21)+2.*viscn(i)
         stifn(i)= one_over_8*aux*aux/max(ms(i),em30)
C        STIFN(I)= STIFN(I)*AUX*AUX/MAX(C21,EM30)
         stifn(i)= max(stifn(i),two*viscn(i)*viscn(i)/max(ms(i),em30))
         viscn(i)= zero
        ENDIF
       ENDDO
C
      RETURN
      END