Dynamics of quasistatic directional crack growth

Abstract

We report extended experimental results on the dynamics of quasistatic directional crack growth in a brittle material. Straight propagation, characterized by both the propagation threshold and the crack tip equilibrium position, enables, within the Griffith energy balance framework, the extraction of the fracture energy and its dependencies with temperature and crack velocity. It is shown that the apparent variations of the fracture energy with crack velocity are an effect of the local temperature at the crack tip, which controls the relative humidity. The oscillating instability of the propagation is described and the results are compared with recent theoretical work, showing that the sensitivity to details of the experimental conditions implies special care for quantitative comparison.