Initiation of cracks in Griffith's theory: an argument of continuity in favor of global minimization (Q625632)

The author proposes to reinforce the interest of the least energy principle criterion for the initiation of a crack in a sound body, by an argument of continuity. In fact it is considered the issue of the initiation of a crack at a notch whose angle is considered a parameter. The result predicted by an old criterion (the Griffith criterion, or so-called, the concept of critical energy release rate) is not continuous with respect to the angle, since no initiation occurs when the angle is positive while a crack initiates when the angle is null. In contrast, the proposed criterion delivers a response which is continuous with respect to the angle, even though the onset of cracking is necessarily brutal when the angle is strictly positive.