fix multisphere/advanced command¶
Examples¶
fix ms all multisphere/advanced
Description¶
Treat one or more sets of atoms as independent rigid bodies. The functionality is identical to the functionality in the fix multisphere command. However, there is one significant improvement: The interaction forces for particle-particle and particle-wall collisions are re-scaled so that the coefficient of restitution is correctly reproduced. This is done by storing the interaction forces for each particle-particle contact, tallying the number of body-body contacts and then re-scaling the contact forces by the number of body-body contacts.
Example: Assume that two bodies A and B are composed of spherical particles A1, A2 (body A) and B1, B2 (body B).
A1 touches B1 - 1 contact A-B in total: The interaction forces between particles A1 and B1 are calculated as usual.
A1 touches B1 and A2 touches B2 - 2 contacts A-B in total: The interaction forces between particles A1 and B1 and between particles A2 and B2 are divided by 2.
Important note: This command requires you to use the option ‘store_force_contact yes’ for all fix wall/gran commands.
Restart, fix_modify, output, run start/stop, minimize info¶
See fix multisphere command.
Restrictions¶
Does not work with fixes freeze and setforce. See fix multisphere command.