CONTROLLED CRACK-GROWTH IN CERAMICS - THE DCB SPECIMEN LOADED WITH PURE MOMENTS

The energy release rate of a double cantilever beam (DCB) loaded with pure bending moments is independent of crack length, allowing stable c rack growth in even truly brittle materials. The method is thus suitab le for measuring fracture toughness and R-curve behaviour of ceramics. This paper describes the development of a new test configuration and reports the testing results from two ceramics: one with constant fract ure-toughness and one possessing R-curve behaviour due to phase transf ormation Stable crack growth was obtained for both materials. (C) 1996 Elsevier Science Limited.