A Study on Three Phases During the Period for Crack Initiation under Impact Load

Abstract

Computer simulations of the dynamic behavior of a three point bend specimen under impact load are performed. Two cases with different load application points at the side and at the middle of the specimen are considered. An elastic-plastic von Mises material model is chosen. Three phases such as impact, bouncing and bending phases are found to be identified during the period from the moment of impact to the estimated time for crack initiation. It is clearly shown that no plastic deformation near the crack tip is appeared at the impact phase. However, it is confimted that the plastic zone near the crack tip emerges in the second phase and the plastic hinge has been formed in the third phase i.e., at the end of which a quasi static state is reached.