particle_template fragments command

Purpose

Command for defining fragments for particle breakage (examples).

Warning

GPU support for this command has not been tested and may not work as expected.

Syntax

particle_template [general_keywords] shape fragments keyword value

General particle_template keywords are documented here. This document only describes the specific keywords for the definition of fragments for particle breakage.

Return to the particle_template documentation.

Keyword

Description

file
obligatory; name of the file containing the center coordinates and the radius
of the spheres forming the fragmented particle (*.csv or *.txt)

scale
factor for scaling up or down the sphere positions and radii
default: 1; range: (0,∞); units: [-]

check_template
yes or no; yes: during the particle template creation checks are performed
(if particles overlap) are performed; no: skip all checks (it is expected that
particles are non-overlapping!), which will speed up particle template creation
default: yes

monte_carlo_steps
number of tries for Monte Carlo approach
default: 10000

bounding_sphere
radius value position vector; value = radius of the bounding sphere
vector = position of the center of the bounding sphere
units: [length]

Examples

particle_template id myFragmentsParticles material limestone shape fragments file myFile.txt

particle_template id pts1 material limestone shape fragments file frag.txt scale 0.1 &
     monte_carlo_steps 1000

particle_template id pts1 material mat1 shape fragments file myFile.txt &
     bounding_sphere radius 1e-2 center (1e-3,0,0)

Description

_images/fragment.png

Fragments are made of spherical particles that are not bonded together. The particle parameters (i.e., positions and radii) are defined via a text file, which name is set by the obligatory keyword file. The format of this text file is:

x1 y1 z1 r1
x2 y2 z2 r2
...
xn yn zn rn

where n is the total number of spheres. Comments can be made in this file via the ‘#’ character.

After the spheres are read, a Monte Carlo procedure is used to assess everything that is needed for the motion integration: mass, center of mass, and the inertia tensor including its eigensystem. The values calculated are written to the logfile.

Per default, also the bounding sphere of the fiber is determined with a Monte Carlo approach. By using the keyword bounding_sphere followed by radius and position this can be done explicitly.

Simulating the breakage of particles requires the usage of the breakparticle/force command.