SUBROUTINE ABQMAIN
C
C     PROGRAM CRP
C                                                   
C
C  THIS PROGRAM CALCULATES THE TRANSIENT RESPONSE OF EQUIVALENT STRESS
C  FOR THE RELAXATION TEST OF A STRAIN HARDENING MATERIAL
C
      DIMENSION S(1)
      DATA XN/5./
      DATA E/20E6/
      DATA XM/-0.2/
      DATA A/2.5E-27/
      DATA SIG0/20.E3/
      DATA TTOT/10E4/
C
      OPEN(UNIT=6,FILE='OUTPUT',STATUS='UNKNOWN')
      H=0.1
      T=.0000001
      S(1)=19999.99
      DM=1./(1.+XM)
      XNM= XN*DM
      XMM= XM*DM
      C=-(A*E)**DM*(1+XM)**XMM
      NINCS=IFIX(TTOT/H)
      NINCPR=IFIX(100./H)
      DO 100 K1=1,NINCS
      S1=S(1)
      CALL FF(S1,F,SIG0,XNM,XMM,C)
      AK1=F*H
      S1=S(1)+.5*AK1
      CALL FF(S1,F,SIG0,XNM,XMM,C)
      AK2=F*H
      S1=S(1)+.5*AK2
      CALL FF(S1,F,SIG0,XNM,XMM,C)
      AK3=F*H
      S1=S(1)+.5*AK3
      CALL FF(S1,F,SIG0,XNM,XMM,C)
      AK4=F*H
      S(1)=S(1)+(AK1+AK4)/6.+(AK2+AK3)/3.
      T=T+H
      IF((K1/NINCPR)*NINCPR.NE.K1)GO TO 10
      WRITE(6,1)T,S(1)
   10 CONTINUE
    1 FORMAT(1X,1P2E10.3)
      IF(T.GE.TTOT)GO TO 110
  100 CONTINUE
  110 CONTINUE
      STOP
      END
      SUBROUTINE FF(S,F,S0,XNM,XMM,C)
      F=C*S**XNM*(S0-S)**XMM
      RETURN
      END