Shore A properties under compression

[Emma Gibney]

Hello,
I am looking at a 19mm thick 63mm diameter disk of shore A rubber. It is being used alternating with aluminum disks to simulate a cervical spine. I know the stiffness of the spine required and the modulus of elasticity of the aluminum but I need to find the required compression on the rubber from elastic modulus. Is there a table or graph of the change in stiffness vs. compression? Or is there a better way of going about finding a modulus of elasticity under specific loading?
Thanks,
Emma

 

[3DDave]

Since rubber typically has low compressibility, the face contact conditions and geometry have a larger contribution than bulk properties would indicate. You will probably have to model this via FEA or make a test model. The problem is that the peripheral surface of the rubber will bulge out and be in tension while other parts will be in compression and the surfaces contacting the aluminum will be in shear. It's too complex for a single number and depends too much on geometry.

 

[GrahamBennett]

3DDave is right. This is a very complex area and you need to talk to someone well versed in FEA to appreciate this. I recommend you email rubberconsultants.com and ask them.

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