RELIABILITY-ANALYSIS OF UNIAXIALLY GROUND BRITTLE MATERIALS

The fast fracture strength distribution of uniaxially ground, alpha si licon carbide was investigated as a function of grinding angle relativ e to the principal stress direction in flexure. Both as-ground and gro und/annealed surfaces were investigated. The resulting flexural streng th distributions were used to verify reliability models and predict th e strength distribution of larger plate specimens tested in biaxial fl exure. Complete fractography was done,on the specimens. Failures occur red from agglomerates, machining cracks, or hybrid flaws that consiste d of a machining crack located at a processing agglomerate. Annealing eliminated failures due to machining damage. Reliability analyses were performed using two and three-parameter Weibull and Batdorf methodolo gies. The Weibull size effect was demonstrated for machining flaws. Mi xed mode reliability models reasonably predicted the strength distribu tions of uniaxial flexure and biaxial plate specimens.