Static crack extension prediction in aluminium alloy at low temperature.

The evaluation of the crack initiation and crack extension under different environmental conditions is very important for many engineering applications. Several crack extension criteria have been proposed in the last decades, but each criterion can be employed only for particular materials, loading configurations, environmental conditions. In the present paper, the R-criterion (minimum extension of the core plastic zone) is modified in order to take into account the temperature dependence. The modified criterion is herein employed to predict the crack path and the crack extension force for an edge-cracked finite plate under tension, by using a simplified procedure to determine the stress-intensity factor (SIF) for different initial crack configurations. Then, results concerning some experimental tests performed on edge-cracked aluminium alloy sheet specimens at different temperatures are reported. Finally, the theoretical results are compared (in terms of crack extension force and crack path) with the experimental data.