failure for hyperelastic material

Hi jisb007;

Failure in hyperelastic testing is pretty straightforward:

In uniaxial (simple) tension, it is the breaking of the specimen.

In pure shear (planar tension), it often is also the breaking of the specimen, HOWEVER, the specimen will typically break at the grips. An additional problem is that, once the width:height ratio of the test specimen is no longer greater than 10:1, it's not really pure shear anymore, so, in a way, the test 'should' end when we're no longer measuring pure shear.

In equal biaxial extension, failure cannot be measured (since the highest stresses are in the tabs, not in the effective gage area)

In simple compression, there really is no such thing as failure; you compress the material as hard as you can, until you / your test frame / your load cell runs out of force.

OK, so that's a little more difficult than I made it sound in the first line of my post... I guess I haven't really heard of elastomers being used for destructive applications, so failure isn't an issue nearly as often as it is for plastics or metals etc.

Hope I helped, sorry if not...

Ron

A strain-based failure criteria should be used in such cases. Hope this can help:

Hi rtmpxr,

Thanks, but the link doesn't work??

It seems it's something wrong out there. There is a html version of the article. Do a search on google using "hyperelasticity failure criteria" and look for the link I sent you.