The tensile strength of brittle materials may be determined using a variation of Equation...

The tensile strength of brittle materials may be determined using a variation of Equation 9.1. Compute the critical crack tip radius for an Al2O3 specimen that experiences tensile fracture at an applied stress of 275 MPa (40,000 psi). Assume a critical surface crack length of 2 × 10–3 mm and a theoretical fracture strength of E/10, where E is the modulus of elasticity.

 (9.1)