Inflatable Rubber Seal Design References 1

[tomecki]

I'm looking for any references on how to analyze and design an inflatable seal.
The seal will be an inflatable rubber ring that will be located in an outer groove of a disc which is to seal against the internal diameter of a pipe.
In my research so far I've found many companies that do custom design and fabrication of these things but I haven't found any references on how to actually analyze one.
We have to perform a design check on an existing product, so need to be able to understand how they are typically designed and analyzed.

Thanks

 

[btrueblood]

FEA analysis with non-linear materials capabilities, typically MSC-Marc and/or Abaqus is useful here. You need to get a sample of the rubber(s) you are intending to make the seal from, and send it to a lab that has experience with non-linear modelling requirements, so that you can find the proper finite element formulation and numerical constants for it. We had good luck outsourcing this to Rubber Consultants in London, UK. Google is your friend. Please post here with any success you have in making your device work.

Once we had done the above, I gained a bit of confidence in our cheap linear FEA analysis methods, and have used it to somewhat optimize a similar design.

Realize one thing, which our company had to learn the hard way despite my a-priori prediction of trouble: A torus, or toroidal segment, which inflates in the inwards direction, has an inherent instability. The centerline of the torus, i.e. the line which will make initial contact for sealing on an internal cylinder, will be in compressive stress in the hoop direction; this can cause all kinds of weird behavior. We (behind the bosses back, until he realized that it was a dumb idea and why) called our product a Sphinct-O-Seal - think about what other sphincters you may have seen look like, and the wrinkles that form in such. We had a trademark design and everything (imagine superimposing a capital "O" with a "*").

Good luck.

 

[GrahamBennett]

I used to work for Rubber Consultants. Their web address is

http://www.rubberconsultants.com.

Mailing address is Rubber Consultants Ltd, Brickendonbury, Hertford, Hertfordshire, SG13 8NL, England.

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