Sol2SPH Particle Behavior

Those forces are:

• Contact forces if they are slave of a TYPE7 interface or rigid walls
• Interaction forces with released particles or genuine particles.

Particles are fully activated based on the following criteria.

• Their master brick is deleted either because:
  • The minimum time step has been reached (/DT/BRICK/DEL)
  • The failure criteria associated to the brick material law has been met
• In case of contact:
  • If an unreleased particle is slave of a TYPE7 interface and enters the gap of the master surface, the brick is deleted and the associated particles are released provided the I_bag flag of the interface is set to 1.
  • If an unreleased particle is within interaction distance of any particle belonging to a different part (including unreleased particles), the master brick is deleted and the associated particles are released. Therefore, no contact interface is required between two Sol2SPH parts.

    
    
    Figure 1. Orange Particles are Released as they are within Interaction Distance of the Yellow Particle. (which belongs to another part)

  • If Isol2sph is set to 2 in /SPHGLO, then particles are not released if the 2 parts belong to the same subset. This option can be useful to prevent unwanted activation of particles at the junction of parts belonging the same physical entities.

    
    
    Figure 2. Isol2sph = 1: Unwanted particles activation / Isol2sph = 2 + subset definition

Particle properties are defined using /PROP/SPH option.

Figure 3. Typical Property for Sol2SPH Particles

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/TYPE34/10
SPH prop example
#                 mp                  qa                  qb            alpha_cs    Skew_ID
                   2                   0                   0                   0         0
#    order                   h             xi_stab                    
         0               125.0                   0                 
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

The smoothing length must be input. A good value for a regular mesh is: (1)

$$h=\frac{1.5\cdot l}{Ndir}$$

Where,

$h$

Smoothing length

$l$

Size of the brick elements

$Ndir$

Number of particle per direction for each solid elements