PARTICLE_DETONATION

Particle
*PARTICLE_DETONATION
"Optional title"
dpid
$x_d$, $y_d$, $z_d$, $t_d$, $R$, fast, gid, sid
Parameter definition
VariableDescription
dpid Detonation point ID
$x_d$, $y_d$, $z_d$ Detonation point
$t_d$ Detonation time
$R$ Detonation radius
fast Flag to activate simplified (fast) detonation path calculation
options:
0 $\rightarrow$ default detonation path
1 $\rightarrow$ simplified detonation path
gid Detonation geometry ID
default: not used
sid Subdomain ID
default: not used
Description

This command complements PARTICLE_HE and it is used to define a detonation point. Multiple detonation points can be defined by specifying more than one command. The detonation radius $R$ limits the distance the detonation front is allowed to propagate through programmed burn.

By default the detonation path is simulated during initialization. The detonation front propagates from particle to particle. Obstacles and air gaps will block the detonation front. Setting fast=1 assumes a simple radial detonation front that does not stop at gaps or obstacles. The detonation time at a given point is then simply $t_d + r / D$, where $r$ is the radial distance from the detonation point and $D$ is the detonation velocity.

The detonation point is neglected if the detonation geometry gid is defined. Instead of detonating at a point, all particles inside the geometry will be initiated at time $t_d$.

The optional parameter sid is used to limit the detonation process one specific subdomain ID.

Example
Detonation point coordinates and time determined with functions

The example consists of a dummy jet against an explosive reactive armour (ERA). It can be advantageous to use functions to describe the detonation parameters instead of preset values. The detonation time of the ERA is based on velocities in the explosive particle subdomain reaching $500 \mathrm{m/s}$. The detonation point coordinates (x,y,z), are determined from the highest velocity in the subdomain. See function ID 1000-1003.


*UNIT_SYSTEM
SI
*PARAMETER
Np = 1000000, "Number of particles"
L = 1.0, "Particle domain reference length"
d = 0.05, "Distance to target"
ang = 60, "Target angle"
X = 0.02, "Target thickness"
X_2 = 0.005, "Target explosives thickness"
Y = 0.08, "Target width"
Z = 0.20, "Target height"
tend = 0.0001, "Termination time"
*TIME
[%tend]
*OUTPUT
[%tend/100], 1.0e-6
*INITIAL_VELOCITY
G, 1, 8000
#
# --- MATERIAL ---
#
*MAT_METAL
"Copper liner"
1, 8900.0, 115.0e9, 0.3, 0, 1, 1
1, 0, 0, 0.3, 1.0, 0.45, 293.0, 1356.0
0, 0, 0, 12.0e6
*FUNCTION
1, 0, 0, 0, strain, stress
90.0e6 + 292e6*epsp^0.31
*PROP_THERMAL
1, 0, 385.0, 0, 0.9, 293.0
*EOS_GRUNEISEN
1, 1.489, 1.99
#
*MAT_METAL
"Mild steel"
2, 7800.0, 210.0e9, 0.3, 0, 0, 1
2
*FUNCTION
2, 0, 0, 0, strain, stress
355.0e6 + 450.0e6*epsp^0.3
#
# --- PARTICLES ---
#
*PARTICLE_DOMAIN
, , [%Np]
[-%L/5], [-%L/3], [-%L/3], [%L], [%L/3], [%L/3]
*PARTICLE_SPH
"Dummy jet"
1
1, 1, 0, 0, 0, , 1
*PARTICLE_SPH
"ERA front"
2
2, 2, 0, 0, 0, , 1
*PARTICLE_HE
"ERA explosive"
3, 8
CompB, 3
*PARTICLE_SPH
"ERA back"
4
2, 4, 0, 0, 0, , 1
#
# --- GEOMETRIES ---
#
*GEOMETRY_PIPE
"Dummy jet"
1
-0.1, 0, 0, 0, 0, 0, 0.003
0.001
*GEOMETRY_BOX
"ERA front"
2, 1
[0], [-%Y/2], -[%Z*0.4], [%X], [%Y/2], [%Z*0.6]
*GEOMETRY_BOX
"ERA explosive"
3, 1
[%X], [-%Y/2], -[%Z*0.4], [%X+%X_2], [%Y/2], [%Z*0.6]
*GEOMETRY_BOX
"ERA back"
4, 1
[%X+%X_2], [-%Y/2], -[%Z*0.4], [%X+%X_2+%X], [%Y/2], [%Z*0.6]
*COORDINATE_SYSTEM_FIXED
1, [%d], 0, 0
[cos(%ang)], 0, [-sin(%ang)], 0, 1, 0
#
# --- DETONATION ---
#
*PARTICLE_DETONATION
1
fcn(1001), fcn(1002), fcn(1003), fcn(1000)
*FUNCTION
"maximum particle velocity in sub-domain 3 minus 500"
1000
vmax_dp(3, 0) - 500.0
*FUNCTION
"x-coordinate at maximum particle velocity in sub-domain 3"
1001
vmax_dp(3, 1)
*FUNCTION
"y-coordinate at maximum particle velocity in sub-domain 3"
1002
vmax_dp(3, 2)
*FUNCTION
"z-coordinate at maximum particle velocity in sub-domain 3"
1003
vmax_dp(3, 3)
*END