Friction Fragmentation

When an explosion occurs near an object, the material from the exploded object will flow past the object, causing friction against the object's surface. This friction may break off pieces of the object, creating fragments.

Settings

 * The production of all fragments can be turned off using the Fragment toggle in the Sim menu in the bottom bar, or using the Sim Settings Menu toggle in the full Sim Settings Menu. Friction fragmentation (as opposed to collision fragmentation or Roche fragmentation can be individually controlled in the Sim Settings Menu.

Models
At each time step, if there is a recent explosion in the same simulation as an object, Universe Sandbox checks whether the wavefront of the explosion has reached the object. If so, Universe Sandbox calculates the velocity of the wavefront relative to the object, Vrel, and the density of the exploded material at the location of the object, ρ, which is calculated from the mass of the exploded object and the current volume of the expanding wavefront.

If the density of the exploded material is greater than 0.03 kg/m3, Universe Sandbox produces Fragment objects. Each fragment is given a mass equal to 1/1000 of the parent object's mass, a density equal to the parent object's, and a radius that is calculated from its own mass and density. The fragment's mass is then subtracted from the parent object's mass. The fragment is given a position that places it randomly on the surface of the parent object, a velocity large enough to escape the surface of the object, and randomly oriented rotation axis with a random rotation period.