MIL-STD-810 Test Method 515.6 –
- Tests how products respond in a noisy environment
- Similar to vibration, it tests the overall endurance of a product
- Three types of acoustical tests: diffuse acoustic noise, grazing incidence noise, and cavity resonance
About MIL-STD-810 Method 515
Method 515 determines how a product responds to a noisy environment. It could be mounted to a jet engine, an external store on an aircraft, or next to a rocket motor on a missile.
You’re testing pressure waves that can range from five to 87 kilopascals. That’s quite a bit of energy in those noisy areas. The pressure waves induce vibration and that vibration can impact equipment performance. Likewise, the vibration frequencies are anywhere from 10 hertz to 10 kilohertz.
With Method 515 testing, you’re looking for the same issues as with vibration, it’s just being applied by driving that energy and putting it into the system through sound waves. Is there fatigue, wire chaffing, breaking solder joints, damage to materials or the structure?
There are three kinds of acoustical tests:
- Diffuse acoustic noise, which is the equivalent of mounting your external stores on an aircraft
- Grazing incidence noise tests equipment located in a ducted area with a very loud environment
- Cavity resonance assesses the resonance energy (vibration) between the cavity itself, like an open bomb or weapons bay, and the material within the cavity
This is a “life” test, so you’re testing endurance of the product. As with every other method in MIL-STD-810, each one of these methods has to be tailored to the specific application.