Contact Strength and Fracture Toughness from Opposite Cylinder Loading Tests

Abstract

Bars loaded by oppositely concentrated forces via rollers are appropriate test specimens for the determination of strength and fracture toughness under contact loading. Test devices are described and solutions for the stress, the stress intensity factor, and the T-stress term are reported. Experimental results are compiled for the contact strength. For most investigated materials, measured contact strengths showed strongly reduced Weibull exponents compared with those from 4-point bending tests. This important effect is attributed to the strong stress gradients near the contact zone.