Determination of the multiaxial failure criteria for alumina ceramics under tension–torsion test

Abstract

Failure probability of ceramic components in multia xial stress state can be predicted using the uniaxi al test results (e.g. Tension Test, 4-Point-Bending Te st) when a suitable multiaxial criterion, which introduces the triaxiality of stress state, is know n. In this article, tension-torsion tests were perf ormed with alumina (Alsint 99.7) specimens from a standard manufacturer under two different load cases. Next experimental results were compared with the numerically calculated effective volume and effective surface values according to different multiaxial fa ilure criteria. It was concluded that the specimens failed due to surface flaws and the normal stress criterio n is the most appropriate criterion for the strengt h prediction of alumina ceramics under multiaxial str ess state. Furthermore, it was shown that the Weibu ll modulus does not play a big role for the prediction of strength of alumina ceramics.