Shock And Vibration Testing

Part of what we do during months of Mini-Rel is subject new instrument designs to a variety of stress testing using severe mechanical shock and sustained periods of vibration. The hope is by shaking the hell out of them we might find unusual defects or design flaws. Everything we can catch here and remedy before a product ends up in customer's hands is desirable.

Out back in the environmental lab I've started working with a young engineer fresh out of school on shock and vibration tests. His name is Scott. He's very approachable, and he's got a demented sense of humor which I like. Most often engineers right out of college show up at their first real job and act like Spock. They're entirely devoid of personality and totally consumed with whatever task is at hand. Real boring to deal with. Scott has somehow managed to avoid acting like a blue blooded Vulcan and get down to brass tacks in the lab which is a nice surprise. So far it's been a good time.

Scott has written an engineering test procedure for subjecting these instruments to a battery of physical shock tests... one of which is pretty harsh. It will simulate what might happen to a unit if someone were to drop it a few feet onto a hard surface. The other tests consist of random vibration for a specified period of time. Vibration testing will simulate an instrument being shipped by truck or aircraft. What will happen to a box when it's in an aircraft cargo bay subjected to turbulence and jet engine vibration for hours? Could a unit be damaged by a ride in a delivery truck hitting potholes on a bad stretch of road? We don't know yet. These are some of the things we have to consider and take into account though. Greasy Guy and myself were asked to contribute some ideas on what to look for or how to set certain conditions on the units while tests are active. I'm satisfied with the procedure at this point and we're set to get started this coming week.

We will be using special sensors called Piezoelectric Accelerometers. I've used them before in the environmental lab at TDS when I was testing microelectronic devices for weapon systems. Piezoelectric Accelerometers are made of a special crystal that generates small amounts of voltage when they are physically moved. Weird stuff. Each time an accelerometer is vibrated the crystals create electricity and that can be fed into instrumentation to precisely measure how much mechanical stress it was subjected to. So, I will be placing one instrument at a time on a vibration table with a few accelerometers, then securing it with tooling, and knocking the shit out of it while I watch to see if it catches fire or blows up. I'm curious to see what if any kinds of problems will be discovered. This is going to be fun because on a small scale it will be like running my own private destruction derby. I get to wreck shit and that's okay.