Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I recently calculated the PSD of the vibration data in a car at constant speed. I would like to know what this means and what if I calculate PSD of the vibration data in a car for the total journey with varying speeds? What do both PSDs signify?

share|cite|improve this question
up vote 1 down vote accepted

I'll make a few guesses here. At a first look, I wouln't think speed would have much effect on the normal vibrational effects. At higher speed we have, greater torque and wind resistance, which would look like a slightly different external loading. More significantly, the wheels are rotating faster, and that probably modifies the normal modes spectrum somewhat. Lastly, the excitation comes from tire noise, and road imperfection (and maybe turbulent air flow), which presumably is skewed more towards higher frequencies at higher speeds.

share|cite|improve this answer
Thank you Omega.. – Dilip Mar 15 '11 at 12:14

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.