Lemaitre damage material model
The Lemaitre damage material model was developed by Lemaitre for an isotropic linear elastic virgin material with stress-strain law as follows
\begin{equation}
\label{eq:22}
\sigma_{ij}=(1-D)C_{ijkl}\epsilon_{kl} \quad D\in[0,1]
\end{equation}
where $D$ represents the extent of damage with the damage evolution law
\begin{equation}
\label{eq:23}
D(\bar{\epsilon})=1-(1-A)\epsilon_{D_{0}}\bar{\epsilon}^{-1}-Ae^{-B(\bar{\epsilon}-\epsilon_{D_{0}})}
\end{equation}
