pyroshock question 1

[mathlete7]

hi,
does anyone have recommendations on the latest/best ways to estimate shock response spectra due to pyrotechnic events. What I'm aware of is:
- NASA Vol VI document: This is some old Martin-Marietta document that give source levels and how to attenuate as a function of distance and structural joints between the pyrotechnic source and the mounting location. I've been told this methodology is very conservative.
- NASA-STD-7003: Has an equation to attenuate levels as a function of distance. I've been told that, since the methodology was based on "complex structure", it has attenuation for number of structural joints built in.

Is anything better out there?

Also, I've been told that, as a rule of thumb, if you can get the shock response spectra below 50 in/s (constant velocity line) then pyroshock won't hurt most electronics. Anyone heard of this criteria before? Is it documented anywhere or is it just a standard rule of thumb?

Thanks for your help...

 

[jimkinney]

Here at KSC we use the NASA-STD-7003 method, which is based on the work done by Martin Marietta for NASA, as well as work done by Boeing. We usually use 40% per joint which is in the middle of the range, with a 3 joint limit.

The 50 ips shock limit comes from MIL-STD-1540 Rev. C and maybe from a Gaberson paper, which I can't find at the moment.

Jim Kinney
Kennedy Space Center, FL