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


Failure using Whitney-Nuismer

Failure using Whitney-Nuismer

Failure using Whitney-Nuismer

I am attempting to make some quick predictions for failure of some notched composite specimens using the Whitney-Nuismer point stress or average stress criterion. I have no data (yet). The default values of d0 and a0 are approx d0=.04 inches and a0=.15 inches respectively but I think I can make much more accurate failure predictions if I calculate these values specific to the laminate. Does anyone know of a purely analytical technique for calculating d0 and/or a0 ?

RE: Failure using Whitney-Nuismer

d0 and a0 are empirical values (not constants) that are a function of material, layup, environment, loading, etc, and cannot be "calculated"

RE: Failure using Whitney-Nuismer

The W-N criteria are simply an attempt to capture the "hole size effect" for composite laminates. As SWComposites stated, d0 (or a0) can only be determined via test (at least in an accurate manner). Also note that the predicted capability can significantly change with relatively small changes of d0.

While there are some approximate d0 values for different material systems and typical layups, these should only be used as reference and to get a feel for what to expect. If you want to make a quick prediction, you are probably better off using preliminary design values that are established for your given type of material system (these would account for notches, mechanically fastened joints, environment, post-impact strength, etc.)


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