Computational and Experimental Investigation of Elastic-Plastic Fracture under Dynamic Conditions.

摘要

Our studies on dynamic fracture have led to the concept of a transition time. The response of a ductile fracture specimen can be characterized by a short-time response dominated by discrete waves, an intermediate-time response dominated by the structural inertia and kinetic energy and a long-time response dominated by deformation energy (or stress work). The transition time, tT, is defined as the time beyond which the total deformation energy exceeds the total kinetic energy of the specimen. Using dimensional and elementary model analyses, we have obtained a simple formula for the transition time. The formula has been verified by two-dimensional and three-dimensional full-field finite element analysis of a dynamically loaded three-point-bend ductile fracture specimen. While the transition time can serve to distinguish the short-time from the long-time response, it has an additional role in nonlinear fracture mechanics which is discussed in the next paragraph.