The word smash would fit very closely. From Oxford Dictionaries:
- [with object] Violently break (something) into pieces:
- 1 [no object] Be violently broken into pieces; shatter:
and also
- [no object, with adverbial of direction] Move so as to hit or collide with something with great force and impact
Your objects are being smashed into pieces in sense 1 as a result of smashing into one another in sense 2.
The term is a little on the informal side, but it fits your needs closely enough that I think it could easily be used and would seem natural in-context. (There is a history of informal words being used with a technical definition in scientific terminology, as for example fuzzy mathematics or particle strangeness, so maybe you could even define a new term.)