c -
c -   Closed form solution for verification of coupled creep and plasticity
c -
c -   PROGRAM sxmcreepintegration
      SUBROUTINE ABQMAIN
c
c - -------------------------------------------------------------------
c -   Closed form solution for Figure 4
c - -------------------------------------------------------------------
      OPEN(unit=22, file="sxmcreepintegration.f4ee",status="unknown")
      OPEN(unit=23, file="sxmcreepintegration.f4pe",status="unknown")
      OPEN(unit=24, file="sxmcreepintegration.f4ce",status="unknown")
      OPEN(unit=25, file="sxmcreepintegration.f4e", status="unknown")

c -   Constants for hardening law and creep law
      y   = 1.e4
      amu = 0.2
      e   = 2.e7
      a   = 2.5e-23
      an  = 5.0
      am  = -0.2
      t1  = 50.

      DO 10 i = 1, 1001
         t = (i-1)*.1
         IF (t.le.t1) THEN
            pstrain = 0.
            estrain = y*t/(t1*e)
            cstrain = a*((y/t1)**an)*(t**(an+am+1.))/(an+am+1.)
            strain = estrain + pstrain + cstrain
            WRITE(24,*) t,",",-cstrain
            WRITE(23,*) t,",",-pstrain
            WRITE(22,*) t,",",-estrain
            WRITE(25,*) t,",",strain
         ELSE
            estrain = y/e + y*(t-t1)/(t1*e)
            pstrain = (t/t1 - 1.)**(1/amu)
            cstrain = (a*(y**an)*(t1**(am+1.))/(am+an+1.))*(t/t1)
     1                 **(am+an+1.)
            strain  = estrain + pstrain + cstrain
            WRITE(24,*) t,",",-cstrain
            WRITE(23,*) t,",",-pstrain
            WRITE(22,*) t,",",-estrain
            WRITE(25,*) t,",",strain
         ENDIF
 10   CONTINUE

      CLOSE(22)
      CLOSE(23)
      CLOSE(24)
      CLOSE(25)

c - -------------------------------------------------------------------
c -   closed form solution for Figure 5
c - -------------------------------------------------------------------
      OPEN(unit=22, file="sxmcreepintegration.f5ce", status="unknown")
      OPEN(unit=24, file="sxmcreepintegration.f5e",  status="unknown")
      OPEN(unit=25, file="sxmcreepintegration.f5ee", status="unknown")

c -   Constants for hardening law and creep law
      y = 2.e4
      t1 = 100.
      a = 2.5e-5
      e = 20.e6
      alpha = 1.e-4
      
      DO 20 i= 1,1001
         t = (i-1)*.1
         estrain = -y*t/(t1*e)
         cstrain = -a*t1/(alpha*y)*(exp(alpha*y*t/t1) - 1.)
         strain = estrain + cstrain
         WRITE(22,*) t,",",cstrain
         WRITE(25,*) t,",",estrain
         WRITE(24,*) t,",",strain
 20   CONTINUE

      CLOSE(22)
      CLOSE(24)
      CLOSE(25)

c - -------------------------------------------------------------------
c -   closed form solution for Figure 6
c - -------------------------------------------------------------------
      OPEN(unit=22, file="sxmcreepintegration.f6ce", status="unknown")

c -   Constants for hardening law and creep law
      y = 2.e4
      t1 = 100.
      a = 2.5e-5
      e = 20.e6
      alpha = 1.e-4
      
      DO 30 i = 1, 1001
         t = (i-1)*.1
         cstrain = -a*(exp(alpha*y) *t)
         WRITE(22,*) t,",",cstrain
 30   CONTINUE

      CLOSE(22)
      END