×
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

Random and sinusoidal vibration analysis

Random and sinusoidal vibration analysis

Random and sinusoidal vibration analysis

(OP)
Hi,
I have some background in vibration and usually use the damped single degree of freedom analogy to help understand and explain vibration analysis. I understand random vibration analysis and familiar with Miles Equation and its uses, however, I am faced with a problem where the inputs are a random vibration level in g^2 per hz (thats OK) and a sinusoidal input (in Gpeak). How do I combine or analyse the two together?
Some of my reading so far indicates that there is no real way of combining the two , but, some attempts are made to convert the sinusoidal to a random level (not strictly possible, I believe) and then the two randoms can be 'summed', say , using a fourth power rule, to arrive at a single random level in g^2 per hz, and the rest is a formality.
Looking forward to some direction.

RE: Random and sinusoidal vibration analysis

Send your random and sine specfications, along with the natural frequency and damping ratio of your system.

I will then show you a method for calculating the response.

Tom Irvine
Email: tomirvine@aol.com
http://www.vibrationdata.com

RE: Random and sinusoidal vibration analysis

(OP)
Random=0.006g^2rms/hz; Gsin= 0.9 (peak); Fn= 100 hz; Q=10

Thanks.

RE: Random and sinusoidal vibration analysis

What is the excitation frequency for the sine input?

Also, I will need to send your a plot.  So please send me your Email address via an Email to

tomirvine@aol.com

RE: Random and sinusoidal vibration analysis

(OP)
To keep this in the open, the frequency is 500 hz, but I have responded by e-mail.

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