c
c
c********************************************************************************
c
c     Example user sub. : HYPELA 
c
c********************************************************************************
c
      SUBROUTINE HYPELA(D,G,E,DE,S,T,DT,NGENS,N,NNN,LAYER,MAT,
     * NDI,NSHEAR)
      implicit real*8 (a-h,o-z)                                               dp
      DIMENSION E(1),DE(1),T(1),DT(1),G(1),D(NGENS,NGENS),S(1),
     C ET(6)
      DO 100 I=1,NGENS
      ET(I)= E(I)+0.5*DE(I)
100   CONTINUE
      POIS=.45
      CONS1=1.0d0/SQRT(1.0d0 + 2.0d0*POIS*pois)
      CONS2=1.0d0 - POIS - 2.0d0*POIS*pois
      EVM=CONS1*SQRT(ET(1)*ET(1)+ET(2)*ET(2)+ET(3)*ET(3)+
     c (.5d0*(ET(4)*ET(4)+ET(5)*ET(5)+ET(6)*ET(6))))
      IF(EVM.GT..105) GO TO 200
      EMOD=.97352d0
      GO TO 500
200   IF(EVM.GT..22) GO TO 300
      EMOD=.464d0
      GO TO 500
300   IF(EVM.GT..345) GO TO 400
      EMOD=.296d0
      GO TO 500
400   IF(EVM.GT..48) GO TO 410
      EMOD=.179d0
      GO TO 500
410   EMOD=.047d0
500   CONTINUE
      SHMOD=EMOD/(2.0d0*(1.0d0+POIS))
      DO 510 I=1,NGENS
      DO 510 J=1,NGENS
510   D(I,J)=0.0d0
      D(1,1)=EMOD*(1.0d0 - POIS)/CONS2
      D(2,2)=D(1,1)
      D(3,3)=D(1,1)
      D(1,2)=EMOD*POIS/CONS2
      D(1,3)=D(1,2)
      D(2,1)=D(1,2)
      D(2,3)=D(1,2)
      D(3,1)=D(1,2)
      D(3,2)=D(1,2)
      D(4,4)=SHMOD
      D(5,5)=SHMOD
      D(6,6)=SHMOD
      DO 520 I=1,NGENS
      DO 515 J=1,NGENS
      S(I)=S(I)+D(I,J)*DE(J)
515   CONTINUE
520   CONTINUE
      RETURN
      END