×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Flexure Pivot Bearing Analysis

Flexure Pivot Bearing Analysis

Flexure Pivot Bearing Analysis

(OP)

I am attempting to analyze the stress and torsional spring rate of rotational flexure bearings, such as shown below.
For those not familiar, these friction-less bearings allow only rotational motion while providing some torsional spring rate. They do this by bending a set of thin cross-section springs which are configured perpendicular to each other.
Initially I assumed I could analyze each arm as a cantilevered beam, with a force applied at the end. I found good information about analysis for large deflection angles, and planned to use that.
However, a few things I have seen indicate that the flexure arms have a uniform stress distribution, which I interpret to mean that it would be a moment-loading case to the cantilevered beam rather than force loading at the end of the beam.
I assume the fact that the arms are perpendicular makes the load case of each arm more complex, because they impart forces on each other.
If I can analyze as a cantilevered beam, I am trying to understand what loading case it would have. I cannot reason it out and it is driving me crazy. I'm making a free body diagram to try to understand it, but would appreciate if someone could point me in the right direction while I'm beating my head against the wall and confusing myself worse.
The 2nd image below shows just the core to help with understanding of how it works. Imagine one of the circular sections fixed and the other being deflected.

RE: Flexure Pivot Bearing Analysis

Have you tried some FEA for a truth-check?
It seems like a relatively straightforward setup. I had always assumed it woudl be a dual cantilever analysis for this case, but you are right in that there is cross talk between the flexures. I have not done the analysis to confirm this statement!

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


Resources

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