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


Random Analysis in Nastran

Random Analysis in Nastran

Random Analysis in Nastran

Hi All,

I am running a random vibration analysis on some structure and I am interested in the RMS stress.
I am able to obtain it in the .op2 file by using STRESS(PLOT,CRMS,NORPRINT)=ALL, but the problem is that it also stores the stress results for the preceding frequency response analysis for each frequency increment which makes the file size huge.
Is there any way of retaining only the RMS results in the .op2 file?

Thanks in advance!

RE: Random Analysis in Nastran

Below is the relevant part of the deck which I am using:

SOL 111


SPC = 1
DLOAD = 10
FREQ = 40


RE: Random Analysis in Nastran

Hello NastranQ,

I do not know if it is possible to obtain only the RMS in the op2 file. Possibly it can be done, but I will explain what I do int these cases.

What I usually do is to reduce the output RMS using a smaller set that contains all the critical components. If you do not know which ones will be critical, take a look at the FRF and it will give you some clue.

If that is not possible or something else, if you have Altair software there is a tool, called Hvtrans, that reads the op2 file and extracts only the subcases and stresses that you select. It could be the solution.

I hope it helps.

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!


eBook - Efficient and Effective Production Support with 3D Printed Jigs and Fixtures
Jigs and fixtures offer manufacturers a reliable process for delivering accurate, high-quality outcomes, whether for a specific part or feature, or for consistency across multiples of parts. Although the methodologies and materials for producing jigs and fixtures have evolved beyond the conventional metal tooling of years past, their position as a manufacturing staple remains constant due to the benefits they offer. Download Now
Overcoming Cutting Tool Challenges in Aerospace Machining
Aerospace manufacturing has always been on the cutting edge, from materials to production techniques. However, these two aspects of aerospace machining can conflict, as manufacturers strive to maintain machining efficiency with new materials by using new methods and cutting tools. 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