Fracture Mechanics In Ceramic Plate

[SiggiN]

Hi!

Suppose you have a case like this:

A simply supported ceramic disc under uniform pressure loading

I am wondering the best way to determine the suitability of the ceramic, and thought I would compare the fracture toughness K_I with K_Ic

However, the geometry factor "Y" and crack size "a" eludes me

K_I = Y*sigma*sqrt(Pi*a)

How is the "Y" determined?

In the absence of a measured "a", what can I assume/do?

What is the correct sigma? Principal stress?

I did a simple linear FEA (assuming isotropic material E = 510GPa and nu = 0.28) to get the stress as indicated above.

Any thoughts on "Y", "a" and "sigma"?

All literature i can find illustrate basic shapes and in-plane tension

Regards
Siggi

 

[Compositepro]

What does fracture toughness have to do with this? You have described a strength problem.