C SOLUTN    SOURCE    CHAT      05/01/13    03:21:51     5004           
       SUBROUTINE SOLUTN(INPLAS,SIG,EPSC,XMAT,DX,X)                             
      IMPLICIT INTEGER(I-N)
       IMPLICIT REAL*8 (A-H,O-Z)                                                
       DIMENSION XMAT(*)                                                        
       IF(INPLAS.EQ.20.OR.INPLAS.EQ.61) THEN                                                    
       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                                                           
       CONS = (1.0D0-EPSC/FS)                                                   
       IF(CONS.GT.0.0D0) THEN                                                   
       X    =-DLOG(CONS)/RS                                                     
       RETURN                                                                   
       ELSE                                                                     
       X    = 1.0D20                                                            
       RETURN                                                                   
       ENDIF                                                                    
       ELSE IF(INPLAS.EQ.22) THEN                                               
       X    = (EPSC/XMAT(6)/SIG**XMAT(8))**(1.0D0/XMAT(7))                      
       RETURN                                                                   
       ELSE IF(INPLAS.EQ.23) THEN                                               
       CON1 = XMAT(7)*SIG/XMAT(8)                                               
       EPSM = XMAT(6)*(0.5D0*(DEXP(CON1)-DEXP(-CON1)))**XMAT(8)                 
       CON2 = XMAT(10)*SIG/XMAT(11)                                             
       R    = XMAT(9)*(0.5D0*(DEXP(CON2)-DEXP(-CON2)))**XMAT(11)                
       EPST = XMAT(12)*EPSM/R                                                   
       S    = XMAT(13)/XMAT(9)*R                                                
       EPSX = 0.0D0                                                             
       IF(SIG.GT.XMAT(16)) EPSX= XMAT(14)+XMAT(15)*SIG                          
       CON1 = EPST+EPSX-EPSC                                                    
       IF(CON1.GT.0.0D0) GO TO 7                                                
       X=1.0D20                                                                 
       RETURN                                                                   
       ENDIF                                                                    
    7  XO  = 0.0D0                                                              
       NIT=0                                                                    
    2  CONTINUE                                                                 
       F1 = CON1-EPST*DEXP(-R*XO)-EPSX*DEXP(-S*XO)                              
       F2 = EPST*R*DEXP(-R*XO)+EPSX*S*DEXP(-S*XO)                               
       IF(DABS(F2).LT.1.0D-10) GO TO 5                                          
       XN = XO - F1/F2                                                          
       IF(XN.LT.1.0D-10) THEN                                                   
       XO = 0.0                                                                 
       GO TO 5                                                                  
       ENDIF                                                                    
       DE = DABS(XN)                                                            
       IF(DE.EQ.0.0D0) DE=1.0                                                   
       ERR= DABS(XN-XO)/DE                                                      
       IF(ERR.LT.1.0D-4) GO TO 5                                                
       NIT= NIT+1                                                               
       XO = XN                                                                  
       IF(NIT.LT.200) GO TO 2                                                   
       WRITE(*,6)                                                               
    6  FORMAT(5X,'** NON-CONVERGENCY IN SOLUTION OF CREEP EQUATION**')          
       STOP                                                                     
    5  X=XO                                                                     
       RETURN                                                                   
       END