PARTICLE_HE
Particle
"Optional title"
sid, overlay
type, gid, follow, $dsf$, -, -, -, $t_{end}$
$\rho_0$, $e_0$, $\gamma$, $v$, $D$
Parameter definition
Description
Discrete particle high explosive domain definition.
The subdomain ID (sid) determines in which order particles are filled into the global domain. In case subdomains are overlapping, the domain with the largest ID will overwrite (remove) particles belonging to domains with lower domain ID's.
Parameter type can be specified as a preset or a user defined explosive. The input parameters used for the presets are presented on our website (Support > Verifier documentation > Verification of explosives).
Available presets:
$\begin{array}{ll} \textsf{ANFO} & \textsf{(Ammonium nitrate fuel oil)} \\ \textsf{C4} & \textsf{(Composition C-4)} \\ \textsf{COMPA} & \textsf{(Composition A-3)} \\ \textsf{COMPB} & \textsf{(Composition B, grade A)} \\ \textsf{HMX} & \\ \textsf{LX-10-1} & \\ \textsf{LX-14-0} & \\ \textsf{M46} & \\ \textsf{MCX-6100} & \\ \textsf{NSP-711} & \\ \textsf{OCTOL} & \textsf{(Octol 78/22)} \\ \textsf{PBXN-110} & \\ \textsf{PBXN-9010} & \\ \textsf{PETN} & \\ \textsf{TETRYL} & \\ \textsf{TNT} & \\ \end{array} $
The follow flag can be used when gid is a GEOMETRY_PART. Setting follow=1 forces the particles to follow the motion of the finite elements (where they are embedded). Note that the elements and the particles represent the same material. Elements are active prior to erosion and the particles are active after erosion. This feature is typically used to model undetonated explosive material with Finite Elements. At detonation the elements are eroded (e.g. ACTIVATE_ELEMENTS) and replaced by the particles.
$1 \lt \gamma \leq 5/3$ determines the ratio $\xi$ between thermal translational energy and molecular spin + vibrational energy.
$\displaystyle{ \xi = \frac{3}{2}(\gamma - 1) }$
overlay > 1 is an optional integer parameter. If used, then the explosive is subdivided into multiple, superposed, layers. Explosive particles in different layers do not interact with each other. overlay > 1 results in a larger high explosive particle radius and a larger time step size during the detonation phase. A negative side effect is a smeared out shock front. Both the time step size and the shock front width are proportional to overlay${}^{1/3}$.
Example
High explosive defined by preset and user
This example demonstrates the different options for parameter type. The model consists of two cylindrical TNT charges. The first PARTICLE_HE command uses the preset and the second command uses a user defined explosive. The data specified in the user defined explosive is identical to the data used in the preset.
