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# FEA simulation? for " O-RINGS" "not what I want"

Member Posts: 3
edited July 2017
Creating an O-Ring is a very simple task as well Creating O-Ring grooves I used an O-Ring Calculator to verify tolerances and fluid type this calculator is really easy to use http://www.applerubber.com/oring-gland-calculator
anyway I just don't believe an o-ring with a material spec of  Silicon Rubber against 6061 aluminum can't be spec'd to
compress instead of just passing right into the 6061. if the parameters of the material could be changed to dynamic within its self and against other objects that would be amazing..
During the "Squish" of the O-Ring the sides expand equally in the groove based on the total amount of compression  applied.
The O-Ring i'm using is a 1 x 3 x 5 (t, id, od) or (dimensions) (thickness) (inside diameter) (outside diameter)  = .039  x .118 x .195, total Squish = .012 which translates to .003 on each side of the O-Ring in the groove,  forces from the id and the outside diameter are combined which is .006 each for a total of .012 / 4 = 3 the groove is .124 and the bore is .186  and groove width is .054 so imagine an ellipse if you will once compressed I realize anFEA Simulator would show potential flaws, I don't have that problem... I want those O-Ring to Squeeze into the bore and expand when released when animated.. I know I can make them elliptical.. That's not what I want to do, it's great for a picture just not great for a demonstration video..
Stephen Normyle (COWBOY)

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Moderator, Onshape Employees Posts: 5,440
edited July 2017
You need a non-linear transient analysis. Take a look at some of our partner apps.
Senior Director, Technical Services, EMEAI
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Onshape Employees, Developers, csevp Posts: 198
Typically to animate this behavior for illustrative purposes, you would use some kind of keyframe animation tool. Clara.io will allow you to keyframe this deformation from circular to squished.

While you could use FEA for a very accurate shape. That seems like overkill. It would require a high end tool. Something like multi physics product will do this.

You could also model the xsection of the oring with a ellipse in Onshape. Then using the H and W values of the ellipse you can then change the values from squished  to a circle... a before and after.

Joe Dunne / Onshape, Inc.
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Member, Moderator, Onshape Employees, Developers Posts: 1,381
edited July 2017

While this isn't exactly what you asked for - many people read these threads and some may be interested to learn that there is a public custom feature that will create 'squashed' O rings - preventing them from showing up as 'interfering' parts.

Philip Thomas - Onshape
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Member Posts: 3
I'm assuming the Public Feature is a script? I did look at the ?DRUM? and that's about all I could do with it

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Member Posts: 3
Thank you Guy's, I did change the shape to and ellipse and now no crashing, I don't understand what Joe is saying about using H & W before and after? During animation or screen shots? Also I figured out how to make a TORX  T-8 & T-10 recess among many other things. Onshape has got me hooked, I love it, I came from Generic CADD 6.1 and never took to Auto-Cad and am totally self trained... a long time ago.. lol
Thanks: Neil, Joe and Phillip
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Member, Moderator, Onshape Employees, Developers Posts: 1,381
@stephen_normyle - A custom feature is a feature written in the same language that our developers use to create the native features in Onshape. When you use a custom feature, it is a first class citizen (meaning that it behaves like any native feature) and will always work moving forwards. You are free to write your own (to help you we have open sourced our source code - see the link below) as well as use those written by others (many are public documents). There is a reference for you here with a collection to get you started and some learning and reference materials.  https://www.onshape.com/customfeatures.

Have fun

Philip Thomas - Onshape