Ceramics FEA

[Jabberwocky]

Hello all,

I am modeling an assembly containing some ceramic components and some titanium - basically a ceramics sandwich. Unfortunately I am not sure which material properties are key for the modeling of the ceramics. I have the basics: Young's modulus, density, Poisson's ratio - but I am not sure what to put for the Tensile limit.

Does anybody have an familiarity with performing FEA analysis on ceramics? I know that there is very little stress shielding, so minor concentrations can lead directly to failure, but what should I be focusing on with this analysis - Principal stress?

For reference, I am using NeiWorks in conjuction with SolidWorks and Nastran.

 

[btrueblood]

Yes, a "simple" principle stress limit criteria is usually used. Note that the tensile limit is typically a small fraction of the compressive limit.

The space shuttle tiles have been modelled many ways, one of the most successful techniques uses a statistical model built into the FEA, to show effects of "real world" property variations. Many, many cases are then run to generate a statistical map of low-margin areas or load conditions that may need more work or tighter inspections, etc. etc.

 

[Jabberwocky]

Thanks for the quick reply!

I had been advised to study up on Weibull modulus as the statistical nature of ceramic strength was mentioned. What should be varied during the different cases? A minor change in the load intensity or direction?