×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Shock Response Spectra and dB's...

Shock Response Spectra and dB's...

Shock Response Spectra and dB's...

(OP)
Hello,
I'm looking at defining some qualification shock response spectrum (SRS) levels for some hardware that is near a pyrotechnic device.  I've seen that most specs recommend testing anywhere from +3dB to +6dB above the limit SRS levels for qualification of hardware.  So my question is this:
When dealing with SRS (where the units are in G's) are the dB levels defined as 10*log(L2/L1) or 20*log(L2/L1)?

I know that when dealing with power spectral density levels you have:
10*log(L2rms^2/L1rms^2) = 20*log(L2rms/L1rms)

However since the units for an SRS aren't rms values I'm not sure if I should be using a factor of 10 or 20 to define decibel levels.

Thanks!

RE: Shock Response Spectra and dB's...

With dBs you use 10 log if the units are  a measure of power or energy (W, J, (ft lb)^2), and 20 log if it is a measure of something that needs to be squared to get to an energy related measurement.

Cheers

Greg Locock

SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources