Failure criteria for FEA of glass

[wz07bw]

I am trying to predict failure of a glass panel subjected to varoius loads.

My FE model consists of solid elements. My question is what do I use for a stress criteria which will predict failure. The model will be used for multiple load cases.

Thank you.

Jim

 

[jedward]

glass fails in tension so you should look for the maximum stress intensity
actual failure levels quite strongly dependent upon surface finish/or roughness, polished surfaces are best and failures generally initiates at the edges

typical values would be 2000 psi for tension but upwards of 40,000 psi in compression
schott has data relating to rate-of-stress application vs failure

Weibull analysis generally used for this kind of failure

be very cautious about the restraints/boundary conditions for any material that is subject to brittle failure
look for works by P Yoder and V Genberg

 

[jedward]

see also "design strength of glass" by Doyle and Kahan

 

[wz07bw]

Thankyou for the insight. I will look into the reference. Initially I was using a max tensile principal stress and I will dig a little deeper. Thanks again.

Jim

 

[Compositepro]

Glass is a brittle material which makes it very flaw sensitive. Glass fibers have a tensile strength of 500,000 psi, far high than monolithic glass. Tempering glass makes it far stronger by simlpy changing the distribution of internal stresses. The right FEA model should be able to take this all into account.

 

[ludvik]

You always want to use principle stresses for glass analysis, not von mises. Von mises = ductile materials, principle = brittle.