Effect of First Reflections in Dynamic Tear Test

Abstract

The dynamic tear (DT) test is often used to obtain key dynamic fracture parameters. Previous work indicates that the first impact waves arriving at the test specimen notch may not create a stress state critical for fracture. In this article, a finite element program for the transient dynamic simulation of an actual DT test is first compared with an analytical solution for the time interval prior to the arrival of wave reflections from the specimen surfaces. The program, which uses a uniform spatial mesh size and does not require singular elements, is then used to determine the transient notch stress field at any time. It is found that the arrival of the first reflected waves generate the stress field necessary for fracture. A critical dynamic stress intensity factor value for the DT test is then estimated. This estimate shows good agreement with other experimentally based results.