11.2.1 Tangential Stiffness ELSEUS

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11.2.1 Tangential Stiffness `ELSEUS`

User-supplied subroutine ELSEUS sets up the tangential rigidity matrix D for nonlinear elasticity in $\dot{{\boldsymbol{\sigma}}}$ = D $\dot{{\boldsymbol{\varepsilon}}}$ .

(Fortran)

      SUBROUTINE ELSEUS( eps, ns, se )

$\begin{figure}\centering \begin{tabbing} out~~\=\textsc{dbl}~~\=\texttt{abcdef... ...ttt{se(ns,ns)}\>Tangential rigidity matrix. \\ [-3ex] \end{tabbing} \end{figure}$

eps: is the total strain vector $\boldsymbol\varepsilon$ _n , for various stress/strain states [Table 11.1].
ns: is the length n of the strain vector, indicates the stress/strain state.
se: is the output tangential rigidity matrix D_{n x n} .

Getting data (Fortran)

      CALL GTC( '../MATERI/YOUNG', young, 1 )
      CALL GTC( '../MATERI/POISON', pois, 1 )

$\begin{figure}\centering \begin{tabbing} out~~\=\textsc{dbl}~~\=\texttt{abcdef... ...extsc{dbl}\>\texttt{pois}\>Poisson's ratio. \\ [-3ex] \end{tabbing} \end{figure}$

young: is the linear elastic Young's modulus E .
pois: is the linear elastic Poisson's ratio $\nu$ .

(file.f)

      SUBROUTINE ELSEUS( EPS, NS, SE )
C
      INTEGER          NS
      DOUBLE PRECISION EPS(NS), SE(NS,NS)
      DOUBLE PRECISION YOUNG
C
C...     Get Young's modulus
      CALL GTC( '../MATERI/YOUNG', YOUNG, 1 )
C
C...     Initialize and set up [SE] for plane stress
      IF ( NS .EQ. 4 ) THEN
         CALL RSET( 0.D0, SE, 16 )
         SE(1,1) = YOUNG + 2000.D0*YOUNG*EPS(1)
         SE(2,2) = YOUNG + 2000.D0*YOUNG*EPS(2)
         SE(3,3) = YOUNG + 2000.D0*YOUNG*EPS(3)
         SE(4,4) = 0.5D0 * YOUNG
      END IF
C
      END

DIANA-9.3 User's Manual - Material Library
First ed.

Copyright (c) 2008 by TNO DIANA BV.