Controlled Fracture Test for Brittle Ceramics

Controlled fracture tests that ensure the full conversion of supplied energy into crack surface energy are required for the accurate determination of the toughness parameters of materials. In this work, a new experimental configuration to perform three-point-bending single-edge V-notch beam stable fracture tests controlled by the crack mouth opening displacement (CMOD) is presented. The CMOD is chosen as the control variable because it is the only parameter that increases throughout the whole fracture process. Results obtained by applying the proposed approach to a fine-grained test sample of the spinel-structured phase of magnesium aluminium oxide are presented. The results obtained demonstrate that the proposed configuration allows stable fracture tests to be performed on extremely brittle ceramics.