Shock Spectrum
Shock Spectrum
(OP)
Folks-
Our customer has imposed a shock spectrum on the laser product we are developing for him. How does one go about approaching such a problem with pencil and paper? Spreadsheet? MathCAD? FEA?
I know this is a wide-open question but perhaps if someone could just point us to a practical reference I'd be much obliged!
Our customer has imposed a shock spectrum on the laser product we are developing for him. How does one go about approaching such a problem with pencil and paper? Spreadsheet? MathCAD? FEA?
I know this is a wide-open question but perhaps if someone could just point us to a practical reference I'd be much obliged!
Tunalover





RE: Shock Spectrum
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Shock Spectrum
Thanks but I suppose I should have mentioned the word "free" reference.
Tunalover
RE: Shock Spectrum
RE: Shock Spectrum
TTFN
Eng-Tips Policies FAQ731-376
RE: Shock Spectrum
Why do you refer me to FAQ731-376?
Tunalover
RE: Shock Spectrum
TTFN
Eng-Tips Policies FAQ731-376
RE: Shock Spectrum
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Shock Spectrum
I have a copy of Harris but it's hopelessly buried in a box in my garage.
Good Luck!
Tunalover
RE: Shock Spectrum
You can readily determine the item's peak acceleration for a given natural frequency from the SRS plot. The key is that the natural frequency of item must be known through analysis and/or test. Upper and lower esimates of the natural frequency may be used if the natural frequency is not precisely known.
The relative displacement might also be a concern. The relative displacement is approximately equal to the SRS acceleration divide by (omega sub n)^2, where (omega sub n)is the natural frequency in terms of radians/sec.
On the other hand, a given item may behave as a multi-degree-of-freedom system. There are some techniques available for applying the SRS to such a system. A finite element analysis is usually required to carry this out.
My favorite method is to synthesize a sample time history to satisfy the SRS. Then perform a modal transient analysis via FEA.
For further information, I have posted a free SRS paper at:
ht
Additional, papers are available at:
http://www.vibrationdata.com/SRS.htm
Thank you,
Tom Irvine