C PARAM1    SOURCE    CHAT      05/01/13    02:09:00     5004           
      SUBROUTINE PARAM1(CMAT,NMAT,AMBDA1,AMBDA2,X1,X2)
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C ROUTINE APPELE DANS ESTIM
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C
C CALCUL DE PARAMETRE DE LA LOI DE FLUAGE PROPRE SPHERIQUE
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C
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8(A-H,O-Z)
      DIMENSION CMAT(NMAT)
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C RECUPERATION DES VALEURS DES PARAMETRES MATERIAU
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      RRSP = CMAT(24)
      VRSP = CMAT(25)
      RISP = CMAT(26)
      VISP = CMAT(27)
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C PARAMETRES INTERMEDIAIRES => EQUATION (2.12-1)
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      URR = RRSP/VRSP
      UII = RISP/VISP
      URI = RRSP/VISP
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C PARAMETRE INTERMEDIAIRE => EQUATION (2.12-2)
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      DELTA = (URR - UII)**2 + 8*URI*(URR + UII) + 16*URI**2
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C INVERSE DES TEMPS CARACTERISTIQUES => EQUATION (2.12-4)
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      AMBDA1 = - (URR + 4*URI + UII + DSQRT(DELTA))/2
      AMBDA2 = - (URR + 4*URI + UII - DSQRT(DELTA))/2
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C PARAMETRES INTERMEDIAIRES => EQUATION (2.12-3)
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      X1 = (AMBDA1 + UII)/(2*URI)
      X2 = 2*URI/(AMBDA2 + UII)
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      END