C
C     Isotropic hardening for UHARDMTS.inp
C
      SUBROUTINE UHARD(SYIELD,HARD,EQPLAS,EQPLASRT,TIME,DTIME,TEMP,
     $     DTEMP,NOEL,NPT,LAYER,KSPT,KSTEP,KINC,
     $     CMNAME,NSTATV,STATEV,NUMFIELDV,
     $     PREDEF,DPREDEF,NUMPROPS,PROPS)
C     
      INCLUDE 'ABA_PARAM.INC'
C     
      CHARACTER*80 CMNAME
C
      DIMENSION HARD(3),STATEV(NSTATV),TIME(*),
     $          PREDEF(NUMFIELDV),DPREDEF(*),PROPS(*)
C     
      IF (EQPLAS.LE.PROPS(2)) THEN
         SYIELD = PROPS(1)
      ELSE IF (EQPLAS.LE.PROPS(4)) THEN
         SYIELD = PROPS(1) + (PROPS(3)-PROPS(1)) *
     $        (EQPLAS - PROPS(2)) / (PROPS(4) - PROPS(2))
         HARD(1) = (PROPS(3)-PROPS(1)) / (PROPS(4) - PROPS(2))
      ELSE IF (EQPLAS.LE.PROPS(6)) THEN
         SYIELD = PROPS(3) + (PROPS(5)-PROPS(3)) *
     $        (EQPLAS - PROPS(4)) / (PROPS(6) - PROPS(4))
         HARD(1) = (PROPS(5)-PROPS(3)) / (PROPS(6) - PROPS(4))
      ELSE
         SYIELD = PROPS(5)
      ENDIF
      STATEV(1) = HARD(1)
      FIELDVARSUM = 0.0D0
      DO I = 1,NUMFIELDV
         FIELDVARSUM = FIELDVARSUM + PREDEF(I)
      END DO
C     FIELD VARIABLES SHOULD SUM TO ONE AND HAVE NO IMPACT ON RESULT
      SYIELD = FIELDVARSUM * SYIELD
      FIELDVARSUM = 0.0D0
      DO I = 1,NUMFIELDV
         FIELDVARSUM = FIELDVARSUM + DPREDEF(I)
      END DO
C     FIELD VARIABLE INCREMENTS SHOULD SUM TO ZERO 
C     AND HAVE NO IMPACT ON RESULT
      SYIELD = FIELDVARSUM + SYIELD
C
      RETURN
      END