A GLOBAL-LOCAL APPROACH TO LENGTHWISE CRACKED BEAMS - DYNAMIC ANALYSIS

A simple model is developed for the calculation of dynamic stress inte nsity factors for lengthwise cracked beams subjected to impact or tran sient loading. The model is based on a Global/Local approach that sepa rates the Global structural dynamics from the Local crack tip zone dom inated by singular stresses. The Global model is that of connected wav eguides while the Local model is based on a novel application of the J -integral that converts dynamic structural resultants directly into st rain energy release rate. The accuracy of this approach is assessed by comparing it to a fully two-dimensional finite element analysis in wh ich the modified crack closure integral is used to calculate the dynam ic strain energy release rate. Both mode I and mode 11 examples are gi ven, and situations with multiple wave reflections are emphasized.