Effects of crack growth on the load-displacement characteristics of precracked specimens under bending

✍ Scribed by T.-J. Chuang; L. Chuck; R.J. Fields; E.R. Fuller Jr.

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 906 KB
• Volume: 18
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(83)90003-6

✦ Synopsis

critical evaluation of the feasibility of obtaining crack growth parameters from quasi-static 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 (u = u_(K,/Iu,#).

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 in order to calculate K,c accurately based on the peak load data, the loading rate has to be set sufficiently fast compared to u,,,, (but below dynamic rates), otherwise, it will generally overestimate its true value whenever slow crack growth occurs during the test; and that for high N materials 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.