Crack propagation and arrest in polymethylmethacrylate

Abstract

Abstract By use of a double‐cantilever‐beam specimen, fast fracture and crack arrest were studied in PMMA. The observation, that the heavily deformed region at the crack tip was confined to a thin wedge of material was confirmed. This result provided support for a onedimensional solid‐mechanics analysis. The computations suggest that the average energy to propagate fast fracture from a sharp crack is only ∼2/3 of that required to initiate it. In addition, the process of very slow crack propagation, leading to arrest, was examined microscopically. At very slow rates the crack was seen to advance in a series of small jumps. The implications of these results with respect to materials development are discussed.