Contact US

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!

*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

Vibration assessment of lab floor to vc-b - query on use of one-third octaves

Vibration assessment of lab floor to vc-b - query on use of one-third octaves

Vibration assessment of lab floor to vc-b - query on use of one-third octaves

I am carrying out a vibration assessment of a concrete floor in a laboratory building. Certain areas of the facility are to achieve the vc-b criteria which is defined in terms of a limiting rms velocity for any given one-third octave band between 0-80Hz. The building is currently under design and so I am using FE to analyse the floor for vibrations due to footfall. My interpretation of the use of one-third octaves is that for each mode between 0-80Hz I should calculate the velocity response. For each one-third octave band I should then calculate the rms velocity by considering the velocity response of all modes that ie within that band. I can then plot a spectra of rms velocity against central frequency over the 0-80Hz range to compare against the allowable velocity.

I am a structural engineer and we do not typically use one-third octave bands so if my interpretation is incorrect then please excuse my ignorance. Any advice on whether the above approach is correct or not would be welcomed.

RE: Vibration assessment of lab floor to vc-b - query on use of one-third octaves

Tricky. How do you ascertain the damping of each mode?

Anyway once you've done that the energy in the third octave is the sum of the energy in the lines in the narrowband spectrum.


Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close