A specimen for a constant stress intensity factor

✍ Scribed by J. Schuve; A.U. De Koning

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 699 KB
• Volume: 9
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(77)90026-1

✦ Synopsis

The purpose of the present investigation was to design a simple specimen for which the stress intensity factor (K) is constant for a substantial range of the crack length. Moreover the crack growth direction should be stable without the necessity of side grooves. The geometry adopted was a rectangular specimen with a central crack loaded by two pins. Values of K were determined in three ways: (1) calculations based on an analytical function in the literature, (2) calculations with the finite-element method and (3) empirical determination based on observed crack growth rates. The agreement between the latter two methods was good, whereas the first method yielded deviating results. By a judicious choice of the width, the height and the locations of the holes for the two pins an approximately constant K-value for a large range of the crack length could be obtained. The tests were carried out on 7075-T6 sheet material.