ANALYSIS OF CRACKED DISK SPECIMENS

A Fredholm integral equation of the plane problem for an arbitrarily loaded disk with an arbitrarily located inner crack is obtained and its solution in the form of double series in power of two parameters is provided. A general formula to define stress intensity factors of central crack is given by which the stress intensity factors for some types of loading are derived and analysed. It is shown that disks loaded by centrifugal forces due to uniform rotation and compressed in the plane of the crack are particularly suitable in fracture toughness testing of brittle materials. It is found that for disks stretched by two forces applied at some distance from the crack the stress intensity factor remains constant in a large range of crack lengths. Therefore they are recommended to be used in subcritical crack growth rate testing. Suitable grips are developed and appropriate correction for their effect is made in the stress intensity factor formula. Recommendations for a choice of optimal dimension ratios for a disk specimen are given. © 1979.