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

Cyclic Fatigue Stress Analysis

Cyclic Fatigue Stress Analysis

Cyclic Fatigue Stress Analysis

Dear All,

For a liquid process system (highly subcooled such as water), is there any general guideline when the system is identified to require cyclic fatigue stress analysis. I am aware that ASME B31.3 and ASME SEC VIII Div.2 part 5 both discuss the relation of number of cycles against the allowable stress at each cycle. However, what is the criteria to be considered to assess that the system requires such analysis or not?


RE: Cyclic Fatigue Stress Analysis

As you mentioned, the number of cyclic condition as stated in the Codes is the basic rule of the requirement for conducting the fatigue analysis for a given operation.
Is there any specific conditions in your system in question?

RE: Cyclic Fatigue Stress Analysis

If a B31.3 piping system is considered High Pressure Fluid Service, fatigue analysis is always required. See K304.8.

For Normal Fluid Service, refer to 302.3.5. Note it’s for displacement stress range, which doesn’t cover cycling stresses due to sustained loads.

Para 302.3.5 refers to appendix W which may provide further guidance.

- You never get what you expect, you only get what you inspect.

RE: Cyclic Fatigue Stress Analysis

Thank you all for the feedback,

I am interested to know if there is any specific criteria for identifying the system of a cyclic process, can we consider a liquid pumping system prone to cyclic conditions due to possible infrequent overpressure by surge. can a cycle be categorized over a time duration or a frequency so we can assess the system being of a cyclic process nature.


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