Commands list
×MENU
EXPAND ALL SORT A-Z

SPH

SPH
*SPH
entype, enid, $\mu$
pid${}_{\mathrm{1}}$, gid${}_{\mathrm{1}}$, $dx_1$, $dy_1$, $dz_1$, $\alpha_1$, $\beta_1$, $v^{max}_1$
.
pid${}_n$, gid${}_n$, $dx_n$, $dy_n$, $dz_n$, $\alpha_n$, $\beta_n$, $v^{max}_n$
Parameter definition
VariableDescription
entype Structure entity type for SPH-structure interaction
options: P, PS
enid Structure entity ID
$\mu$ Friction coefficient
pid${}_{\mathrm{1}}$ Part ID
gid${}_{\mathrm{1}}$ Geometry ID that defines a region in space that will be filled with SPH nodes
$dx_1$ Node spacing in x-direction
$dy_1$ Node spacing in y-direction
default: dy${}_{\mathrm{1}}$ = dx${}_{\mathrm{1}}$
$dz_1$ Node spacing in z-direction
default: dz${}_{\mathrm{1}}$ = dx${}_{\mathrm{1}}$
$\alpha_1$ Linear artificial viscosity term
default: 0.1
$\beta_1$ Quadratic artificial viscosity term
default: 0.5
$v^{max}_1$ Max expected velocity
default: 10% of the sound speed in the material
pid${}_n$ Part ID
gid${}_n$ Geometry ID that defines a region is space that will be filled with SPH nodes
$dx_n$ Node spacing in x-direction
$dy_n$ Node spacing in y-direction
default: dy${}_{\mathrm{n}}$ = dx${}_{\mathrm{n}}$
$dz_n$ Node spacing in z-direction
default: dz${}_{\mathrm{n}}$ = dx${}_{\mathrm{n}}$
$\alpha_n$ Linear artificial viscosity term
default: 0.1
$\beta_n$ Quadratic artificial viscosity term
default: 0.5
$v^{max}_n$ Maximum expected velocity
default: 10% of the sound speed in the material
Description

Defines SPH geometries/grids and interaction between SPH nodes and structure. Even if no interaction with FE parts is defined, the first line must be left blank. By default, geometries are filled with SPH nodes based on a cartesian grid. When more than one SPH part is defined, the node generation process considers an automatic Boolean operation to prevent any node overlapping. Geometries are filled successively following the definition order.

Meshing options:

$dz = z_{max}-z_{min} \; \rightarrow \;$ 2D model is generated.

$dy = dz = -2 \; \rightarrow \;$ The axisymmetric filling routine is activated, considering a random distribution of the initial rotation angle.

$dy = dz = -1 \; \rightarrow \;$ The axisymmetric filling routine is activated, without a random distribution of the initial rotation angle (default option when BC_SYMMETRY is used).

Note that for the axisymmetric filling, the revolution axis is $x$ and the reference mesh must be in the $XY$ plane.

Example
*UNIT_SYSTEM
SI
*PARAMETER
R = 50.0e-3
dx = 5.0e-3
Nb = %R/%dx
*PART
"Reference mesh"
1, 1
"SPH Axi -1"
2, 2
"SPH Axi -2"
3, 2
*COMPONENT_BOX
"Reference mesh"
1,1,%Nb,%Nb,1
0.0,0.0,-%dx,%R,%R,%dx
*GEOMETRY_PART
"option -1"
2
1
*GEOMETRY_PART
"Option -2"
3,3
1
*COORDINATE_SYSTEM_FIXED
"local csys for option -2"
3,0.0,0.0,2.0*%R
*MAT_RIGID
1, 7800.0
*MAT_JC
2, 2700, 70e9, 0.3
350e6
*SPH
0
2, 2, %dx, -1.0, -1.0
3, 3, %dx, -2.0, -2.0
*END
Top: No random distribution of rotation angle (option -2), Bottom: Random distribution of rotation angle (option -1).
Top: No random distribution of rotation angle (option -2), Bottom: Random distribution of rotation angle (option -1).