How are electronics hardened against extreme accelerations?

How does one protect electronics against extreme accelerations/impacts? I mean accelerations of at least 2000g, possibly an order of magnitude more; essentially "payload" of an artillery shell.

The circuitry would consist of some radio receiver, a controller of an electric primer, and some kind of power source to keep both running for a couple minutes.

Size and weight aren't much of a problem (<1m, <1ton) but the acceleration would be sustained over about 1s of time, not just a momentary impact, also the initial jerk ($\dot{a}$) would be an extreme spike.

• Is this question about what problems specifically may arise with the electronics? It goes without saying that anything that isn't solid-state is out of the question, other than that it seems the same principles that apply to the rest of the mechanical design would apply to the electronics. Also, is this a linear acceleration of 2000g over 1s? Nov 26 '15 at 9:53
• @AsadSaeeduddin: Thing is with these accelerations definition of "solid state parts" changes... for example electrolytic capacitors definitely cease to be solid state. So a good answer would both tell what kinds of parts are still permissible (probably a much smaller family than what is no longer allowed) and how to protect the whole board from shattering (I'd bet some kind of epoxy, but again I'm not sure if epoxy doesn't go liquid at >2000g). Yes, linear acceleration.
– SF.
Nov 26 '15 at 9:59
• That implies the thing will eventually be travelling at a velocity of about 19000 m/s relative to what I assume is air. For reference, the fastest projectile mankind's come up with so far is about 16000 m/s. What is this thing anyway? Nov 26 '15 at 10:12
• @AsadSaeeduddin: Actually, >66000m/s. Of course it very quickly burned up in the atmosphere. My question is related to this discussion.
– SF.
Nov 26 '15 at 11:55

There are many considerations, some of which are secret or proprietary to those that figured them out.

A major issue is how to connect the electronic parts and hold them in place. Individual transistor, resistor, and even ICs are small and light and fully encapsulated in epoxy or some other material. Keeping these parts in place and properly connected to each other is a tough problem.

I don't have any good direct answers, but I do remember reading about how the first proximity fuses for anti-aircraft shells were developed during WWII. They made it work back then with vacuum tubes, so it should be possible today with smaller and lighter semiconductors. If I remember right, one of the breakthroughs was silver in the solder.

Go read up on the history of proximity fuses in WWII. It's a interesting bit of history by itself, and you should be able to find pointers to how the electronics was made to survive, which might lead to pointers to more modern research.

Of course one has to wonder why someone would be asking this here. If you're professionally designing electronics for artillery shells, you should have access to the classified research. If you don't have access to this information, then it's hard to see a legitimate reason you should be privy to the information. I wouldn't tell you more even if I did know it.

• In this particular case the reason is more benign: a discussion on feasibility of delivery of raw materials to LEO through a "space gun", and in particular the bare minimum of systems required to circularize the orbit - the primer would light a solid rocket booster, not an explosive.
– SF.
Nov 26 '15 at 14:51
• It's been a while since I've seen the internals of an integrated circuit chip but I recall them having micro filaments of gold linking the pins to the circuitry. This made them less robust than vacuum tubes.
– Fred
Nov 27 '15 at 3:32