viscbb.F

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C Non linear viscous model based on Bergstrom Boyce
C output: the creep strain increment DGAMMA
C-----------------------------------------------
!||====================================================================
!||    viscbb      ../engine/source/materials/mat/mat100/viscbb.F
!||--- called by ------------------------------------------------------
!||    sigeps100   ../engine/source/materials/mat/mat100/sigeps100.F90
!||    sigeps95    ../engine/source/materials/mat/mat095/sigeps95.F
!||====================================================================
        SUBROUTINE viscbb ( NEL, FP, TBNORM, A1,EXPC, EXPM , KSI , TAUREF, DGAMMA ) !BERGSTROM BOYCE MODEL
C-----------------------------------------------
C   I M P L I C I T   T Y P E S
C-----------------------------------------------
#include "implicit_f.inc"
C----------------------------------------------------------------
C  I N P U T   A R G U M E N T S
C----------------------------------------------------------------
      INTEGER,  INTENT(IN) ::       NEL
C  
      my_real,  INTENT(IN) :: a1,expc, expm , ksi ,tauref
C
      my_real, DIMENSION(NEL), INTENT(IN) ::  tbnorm 
C
      my_real, DIMENSION(NEL, 3,3) , INTENT(IN) ::  fp 
C----------------------------------------------------------------
C  O U T P U T   A R G U M E N T S
C----------------------------------------------------------------
      my_real, DIMENSION(NEL), INTENT(OUT) ::  dgamma
C----------------------------------------------------------------
C  I N P U T  O U T P U T   A R G U M E N T S
C----------------------------------------------------------------
C----------------------------------------------------------------
C  L O C A L  V A R I B L E S
C----------------------------------------------------------------
      INTEGER    I
 
      my_real     
     .   temp, lpchain(nel), ip1(nel)
C----------------------------------------------------------------
C----------------------------------------------------------------
         DO i=1,nel         
          ip1(i) = fp(i,1,1)**2 + 
     .             fp(i,2,2)**2 + 
     .             fp(i,3,3)**2           
          lpchain(i) = sqrt(max(zero,third*ip1(i)))          
          !MAXL = MAX(MAXL, LPCHAIN (I))
          temp = max(em20,lpchain(i) - one +ksi)       
          dgamma(i) = a1* exp(expc*log(temp))* ((tbnorm(i)**expm)/max(em20, tauref**expm))   
         ENDDO
 
      RETURN
      END
C----------------------------------------------------------------