Abstract

Ceramic laminates with residual stress arising from thermal mismatch, show higher strength and larger apparent fracture toughness than their monolithic counterparts. For an effective improvement under in-service conditions, such enhancement should be reflected on the blunt-contact behaviour, characterized by an inhomogeneous multiaxial stress state. The contact strength test is an interesting alternative to traditional testing methods to evaluate contact-focused resistance of brittle materials. Because of the Hertzian-like stress state, high stresses can be generated far from the surface, producing failure from the weakest part of the structure, and this is especially true in pre-stressed materials, such as the one herein studied. In this work, experimental tests on a laminated ceramic are reported together with a FE analysis, showing a noteworthy improvement, although in some cases the composite structure may fail in an inner layer, and providing general tools for designing contact-resistant structures.