entype, enid, N${}_p$, $\mu$, $pfac$, $c_{dec}$, xsmooth, $t_{end}$
$x_0$, $y_0$, $z_0$, $x_1$, $y_1$, $z_1$
bc${}_{x0}$, bc${}_{y0}$, bc${}_{z0}$, bc${}_{x1}$, bc${}_{y1}$, bc${}_{z1}$
$\delta_0^{max}$, ctype, SPH${}_{uniform}$
Parameter definition
Variable | Description |
---|---|
entype | Structure entity type for particle structure interaction |
enid | Structure entity ID |
N${}_p$ | Total number of particles |
$\mu$ | Particle-structure contact friction |
$pfac$ | Particle-structure contact stiffness |
$c_{dec}$ | Impulse transfer smoothing time (gas-structure) |
xsmooth | Spatial impulse smoothing level |
$t_{end}$ | Particle deactivation time |
$x_0$ | Particle domain minimum x-coordinate |
$y_0$ | Particle domain minimum y-coordinate |
$z_0$ | Particle domain minimum z-coordinate |
$x_1$ | Particle domain maximum x-coordinate |
$y_1$ | Particle domain maximum y-coordinate |
$z_1$ | Particle domain maximum z-coordinate |
bc${}_{x0}$ | Boundary condition at $x=x_0$ |
bc${}_{y0}$ | Boundary condition at $y=y_0$ |
bc${}_{z0}$ | Boundary condition at $z=z_0$ |
bc${}_{x1}$ | Boundary condition at $x=x_1$ |
bc${}_{y1}$ | Boundary condition at $y=y_1$ |
bc${}_{z1}$ | Boundary condition at $z=z_1$ |
$\delta_0^{max}$ | Max allowed initial contact penetration |
ctype | Particle-structure contact type |
SPH${}_{uniform}$ | Flag to swith from uniform SPH node mass to uniform SPH smoothing length |
Description
This command is used to define a global domain and general settings for SPH and discrete particles. $N_p$ defines the total number of particles. The distribution of particles to the different sub-domains (PARTICLE_HE, PARTICLE_AIR, PARTICLE_SOIL, PARTICLE_SPH) is automatic.
The spatial impulse smoothing option smears out transferred impulses (in the particle-structure interaction) to more than one element face. xsmooth is an integer that defines the size of the region where impulses are distributed. xsmooth=1 means that only the direct neighbours of an impacted face will share a fraction of the impulse. With xsmooth=2 the impulse is distributed to both the direct and to the second level neighbours. Typical xsmooth parameters are in the range 1 to 10.
Particles overlapping the underlying Finite Element mesh by more than $\delta_0^{max}$ will be removed from the model during initialization.
When working with SPH and materials with significanlty different properties (density and/or stiffness), it is adviceable to set SPH${}_{uniform}$=1 and slide=1 (in PARTICLE_SPH). Sticking between materials with significanlty different properties is better modelled using MERGE than through SPH kernel function interactions.