C EQUATN    SOURCE    CHAT      05/01/12    23:44:36     5004           
       SUBROUTINE EQUATN(INPLAS,SIG,TIME,DT,XMAT,DEPSCP,DEPSCS)                 
      IMPLICIT INTEGER(I-N)
       IMPLICIT REAL *8 (A-H,O-Z)                                               
       DIMENSION XMAT(*)                                                        
       IF(INPLAS.EQ.20) THEN                                                    
C                                                                               
C   BLACKBURN EQUATION                                                          
C                                                                               
       F1    = XMAT(6)*DEXP(XMAT(7)*SIG)                                        
       F2    = XMAT(8)*SIG**XMAT(9)                                             
       FS    = F1 + F2                                                          
       R1    = XMAT(10)*DEXP(XMAT(11)*SIG)                                      
       R2    = XMAT(12)*SIG**XMAT(13)                                           
       RS    = R1 + R2                                                          
       T1    = XMAT(15)*SIG                                                     
       SINH  = 0.5D0*(DEXP(T1)-DEXP(-T1))                                       
       G1    = XMAT(14)*SINH**XMAT(16)                                          
       G2    = XMAT(17)*DEXP(XMAT(18)*SIG)                                      
       GS    = G1 + G2                                                          
       DEPSCP= FS * RS * DEXP(-RS*TIME)                                         
       DEPSCS= GS                                                               
       RETURN                                                                   
C                                                                               
       ELSE IF(INPLAS.EQ.61) THEN                                               
C                                                                               
C   BLACKBURN_2 EQUATION                                                          
C                                                                               
       F1    = XMAT(6)*DEXP(XMAT(7)*SIG)                                        
       F2    = XMAT(8)*SIG**XMAT(9)                                             
       FS    = F1 + F2                                                          
       R1    = XMAT(10)*DEXP(XMAT(11)*SIG)                                      
       R2    = XMAT(12)*SIG**XMAT(13)                                           
       RS    = R1 + R2                                                          
       T1    = XMAT(15)*SIG                                                     
       SINH  = 0.5D0*(DEXP(T1)-DEXP(-T1))                                       
       G1    = XMAT(14)*SINH**XMAT(16)                                          
       G2    = XMAT(17)*SIG**XMAT(18)                                      
       GS    = G1 + G2                                                          
       DEPSCP= FS * RS * DEXP(-RS*TIME)                                         
       DEPSCS= GS                                                               
       RETURN                                                                   
C
       ELSE IF(INPLAS.EQ.22) THEN                                               
C                                                                               
C   RCC-MR EQUATION FOR 1S MATERIAL (SS 316LN)                                  
C                                                                               
       DEPSCP= 0.0D0                                                            
       DEPSCS= 0.0D0                                                            
       TFP   = XMAT(9)*SIG**XMAT(10)                                            
       IF(TIME.LT.DT) TIME=DABS(DT)                                             
       IF(TIME.LE.TFP)                                                          
     & DEPSCP=(XMAT(6)*XMAT(7))*(TIME**(XMAT(7)-1.0D0))*(SIG**XMAT(8))          
       IF(TIME.GT.TFP)                                                          
     & DEPSCS=XMAT(11)*SIG**XMAT(12)                                            
       RETURN                                                                   
       ELSE IF(INPLAS.EQ.23) THEN                                               
C                                                                               
C   RCC-MR EQUATION FOR 2S MATERIAL (SS 304LN)                                  
C                                                                               
       CON1  = XMAT(7)/XMAT(8)*SIG                                              
       EPSM  = XMAT(6)*(0.5D0*(DEXP(CON1)-DEXP(-CON1)))**XMAT(8)                
       CON2  = XMAT(10)/XMAT(11)*SIG                                            
       R     = XMAT(9)*(0.5D0*(DEXP(CON2)-DEXP(-CON2)))**XMAT(11)               
       EPSTR = XMAT(12)*EPSM                                                    
       S     = XMAT(13)/XMAT(9)*R                                               
       EPSX  = 0.0D0                                                            
       IF(SIG.GT.XMAT(16)) EPSX=XMAT(14)+XMAT(15)*SIG                           
       T1 = R*TIME                                                              
       T2 = S*TIME                                                              
       F1 = 0.0D0                                                               
       F2 = 0.0D0                                                               
       IF(DABS(T1).LT.100.0) F1=DEXP(-T1)                                       
       IF(DABS(T2).LT.100.0) F2=DEXP(-T2)                                       
       DEPSCP= EPSTR*F1+EPSX*S*F2                                               
       DEPSCS= EPSM                                                             
C                                                                               
       ENDIF                                                                    
       RETURN                                                                   
       END