6.1.4 Rate-dependent Cracking

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6.1.4 Rate-dependent Cracking

The rate-dependent cracking model may be added to the previously specified cracking criterion.

(syntax)

$\begin{figure}\centering \begin{tabbing} \texttt{'MATERI'} \\ [-1.0ex] \rule{14... ... * \>\>\texttt{RATDEP}\>\texttt{\textit{m}}$_{r}\,$ \end{tabbing} \end{figure}$

RATDEP

m is the dependency parameter m (m > 0 )from

$\displaystyle \dot{{\sigma }}_{{nn}}^{}$ = h $\displaystyle \dot{{\varepsilon }}_{{nn}}^{{\mathrm{cr}}}$ + m $\displaystyle {\frac{{\partial \dot{\varepsilon }_{nn}^{\mathrm{cr}}}}{{\partial t}}}$

(6.2)

The first term denotes the tension softening contribution in which h is the slope of the softening curve [Fig.6.2]. The second term is the rate dependency contribution according to Sluys [100].

**Figure 6.3:** Rate-dependent cracking - example
$\begin{figure}\begin{footnotesize}\setlength{\unitlength}{1cm} \begin{picture... ...enterline{\raise 4.0cm\box\graph} } \end{picture}\end{footnotesize} \end{figure}$

As a result of the strain rate dependency, the stress-strain curves show an increase of the maximum tensile strength f_t and a residual strength m $\dot{{\varepsilon }}$ under dynamic loading [Fig.6.3].

(file.dat)

 'MATERI'
 1   CRACK   1
     CRKVAL  2.0
     TENSIO  1
     TENVAL  0.4E-3
     TAUCRI  1
     BETA    0.0001
     RATDEP  0.2

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

Copyright (c) 2008 by TNO DIANA BV.