Significance of Shock Duration
Significance of Shock Duration
(OP)
I have an optical instrument that I am drop (shock) testing to determine a spec to give to a packaging engineer who will design the shipping container. What significance does the shock duration have? If I still achieve the same g level does it matter? Is it just a matter of the effects of larger displacements that go along with longer durations?





RE: Significance of Shock Duration
So, for a given peak g level a shorter pulse puts less eenrgy in anyway, spread over a greater bandwidth. Even if you normalise for energy input in the event then it is still putting less energy in per unit bandwidth.
Now, at some point this argument does fall apart, since if you make the pulse long enough, but keep the total energy input the same, you minimise the damage.
It's actually an impedance matching problem - a sufficiently fast pulse does no damage, a sufficiently slow pulse does no damage, it's the bit in between where real life operates.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Significance of Shock Duration
Therefore, if you are trying to protect against a drop, you need to determine the maximum KE and the maximum allowable acceleration and that will determine the duration required to keep the acceleration below the critical level.
TTFN
RE: Significance of Shock Duration