Would "on" be the right preposition to use in this context? Other options would be explodes "by contact" or "after contact". Is any of these used when talking about such devices or is there a different expression altogether?
In military they use the following phrase:
- The grenade (explosive) detonates (explodes) on (upon) impact.
Both "on" and "upon" are used interchangeably.
In 3D-modelling and animation the word "collide" is mostly used instead of "impact"
- The particles spawn new particles on (upon) collision.
- The object blasts on (upon) collision.
Besides "on (upon) impact" there are also popular "on fuse", "by trigger" and "on timer".
Another possible preposition is "after"
- The incendiary grenade detonates after impact. (some time after impact)
By - can be seen in some articles and journals but isn't the proper preposition to use with the words "contact, collision, impact"
It mostly means "by means of something". You need to either use a computer or detonation device, some controller to detonate the bomb.
On and upon (a formal on) mean "when in contact with" or "at the time of (when)"
After means "in the time following"
Here's the NGram Viewer Chart