How is the power of explosives measured? That is, what’s the metric for knowing how much force a given explosive will exert at a given distance per unit of explosive material?
I know fission/fusion weapons have kilotons, and there’s brisance for determining the breaking power of an explosive charge, but how do you calculate how much material is needed for a charge?
Is there some way to know how many psi an unshielded object at distance x will experience from the shockwave from an explosive of mass y?
The vast majority of explosives used are for mining purposes. There the purpose is to have just enough explosive down a hole to break the surface and immediate rock but not blash into the air. This is dependent on the rock type and the type of mining being performed and in general relies on the experience of the shotfirer to get it right.
Other tests for explosives measure different parameters such as velocity of detonation or how much a lead block is deformed by a given amount of explosive.
Often explosives are compared to the same amount of TNT but the official reference explosive is picric acid. See
The military has all kinds of stats on this. In USAF parlance “weaponeering” is the task of deciding which munition in what quantity to apply to any given target to achieve a particular desired result.
Essentially you start with an estimate of how resilient the target is, knowledge of how accurately (statistically speaking) you can place the munition, and how much oomph of what kind you get from each weapon in your arsenal.
For any given kind of construction, testing gives us pretty good metrics for how hard you have to hit it to damage, destroy, or obliterate it. This testing is used to generate tables for various construction types indicating the blast overpressure they can withstand. As well as their resistance to fire and to fragments / shrapnel.
“overpressure resistance” is probably the most Googlable term you’ll come up with in this general direction.