A STATISTICAL MODEL OF BRITTLE FRACTURE （脆性断裂的统计模型）.pdf

J. Mrch. Phys. SolidsVol. 34, No. 5, pp. 417-491, 1986 0022-5096/86$3.00+0.00 Printedin GreatBritain. Pergamon Journals Ltd. A STATISTICAL MODEL OF BRITTLE FRACTURE BY TRANSGRANULAR CLEAVAGE TSANN LIN, A. G. EVANS? and R. 0. RITCHIE Materials and Molecular Research Division, Lawrence Berkeley Laboratory, and Department of Materials Science and Mineral Engineering, University of California, Berkeley, California, U.S.A. (Received 17 .Jlane 1985 ; in revised,form 24 December 1985) ABSTRACT A MODEL for brittle fracture by transgranular cleavage cracking is presented based on the application of weakest link statistics to the critical microstructural fracture mechanisms. The model permits prediction of the macroscopic fracture toughness, K,,, in single phase microstructures containing a known distribution of particles, and defines the critical distance from the crack tip at which the initial cracking event is most probable. The model is developed for unstable fracture ahead of a sharp crack considering both linear elastic and nonlinear elastic ~‘elastjc~plastic”) crack tip stress fields. Predictions are evaluated by comparison with experimental results on the low temperature flow and fracture behavior of a low carbon mild steel with a simple ferrite/grain boundary carbide m