Analyses of cleavage crack arrest experiments: influence of specimen vibration

The crack propagation resistance of a low alloy bainitic steel used for nuclear pressure vessels was studied. Thermal shock experiments were carried out on pre-cracked discs. These tests were analyzed using the finite element method according to various assumptions, from elastic-static to full transient elastic-viscoplastic analysis. The crack propagation was modeled using node release technique. It was shown that crack deceleration at the end of the propagation greatly modifies the stress field at crack tip, due to interactions with structural vibrations. Therefore, it may be inaccurate to transfer the arrest toughness obtained from specimens under static analysis to components.