×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• 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.

# FEA 2D to 3D extrapolation

## FEA 2D to 3D extrapolation

(OP)
I've ran some 2D FEA simulations on some cylindrical permanent magnets and measured their magnitudes for increasing radii. After a certain distance away from the magnet the magnitudes are constant at a given radius regardless of rotation, and governed by the equation y=a/r^-b. 'b' is an integer equal or greater than 2, depending on the pole count (b=#poles/2+1).

However, by the time these equations become valid the magnet in question could be better approximated as a point source rather than an infinitely long cylinder as simulated. Perhaps an analogous situation is the point charge/line charge/sheet charge series of equations, where electric field strength is a function of r^2, r^1, and r^0 (i.e. constant) respectively. That analogy leads me to believe that I can better approximate reality by increasing the exponent 'b' by 1 (and adjusting 'a' as necessary).

So if the original equation is y=100/r^2, the new equation might be y'=200/r^3.

Does this seem like a valid approach?

### RE: FEA 2D to 3D extrapolation

Yes. But it ignores the 3 dimensional lobe pattern of the field, and so it is a rough guide at best in th near field. In the far field then if it is a point source the answer is the pen and paper solution.

Cheers

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.

#### 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
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™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:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!