Effects of Crack Growth on the Load-Displacement Characteristics of Precracked Specimens Under Bending

摘要

A critical evaluation of the feasibility of obtaining crack growth parameters from bend tests is presented. First derived are the governing differential equations which characterize the time-history of bend test parameters for a given elastic material exhibiting power law crack growth behavior. A numerical solution scheme is then developed which is capable of solving the initial value problem, thus quantitatively assessing the influence of crack growth on the load-displacement output. The results of this analysis indicate that for high N materials (where N is the exponent in the power law crack growth equation) the flexural test method gives a broad error band in N prediction and hence is not a reliable technique. However, it can be used by a designer to quickly screen the new materials with high N values which are potential candidates for structural application.