MAT_EXPLOSIVE_JWL
Material properties
"Optional title"
mid, $\rho_0$, $E$, $\nu$
$\sigma_0$, $Q$, $C$
$A$, $B$, $R_1$, $R_2$, $\omega$, $e_0$, $D$
Parameter definition
Description
This is a model for explosive materials. It is currently only implemented for Finite Elements. Undetonated material is treated as elasto-plastic with a (J2) flow stress, according to:
$\displaystyle{\sigma_y = \sigma_0 + Q \left( 1 - \mathrm{exp} (-C \varepsilon_p)\right)}$
At detonation the chemical energy $e_0$ is released and all shear stresses are set to $0$. The pressure $p$ is defined accoding to the JWL equation-of-state:
$\displaystyle{ p = A \left( 1 - \frac{\omega}{R_1 V} \right) \mathrm{e}^{-R_1 V} + B \left( 1 - \frac{\omega}{R_2 V} \right) \mathrm{e}^{-R_2 V} + \omega e}$
where $V$ is the relative volume:
$\displaystyle{ V = \rho_0 / \rho}$
The model uses a programmed burn assumption and at least one detonation point must be defined with the command DETONATION.
Example
Contact detonation
A C4 charge modelled with Finite Elements and MAT_EXPLOSIVE_JWL. Quadratic elements are well-suited for this purpose, if combined with the command LOAD_ELEMENT_SMOOTHING. The smoothing command is essential for mitigating spurious high-frequency oscillations on element level. A programmed burn approach is employed, with the ignition point defined using the command DETONATION.
