Coplanar perturbation of a crack lying on the mid-plane of a plate

摘要

Several groups have studied experimen?tally the deformation of the front of mode I cracks propagating quasistatically along the interface between bonded plates. The theoretical interpretation pf such experiments has always been based up to now on a for?mula of Rice (ASME J Appl Mech 52:571-579, 1985); this formula provides the first-order variation of the local mode I stress intensity factor resulting from some small, but otherwise arbitrary coplanar perturbation of the front of a semi-infinite crack in an infinite body. To be applicable to bonded plates, this formula requires that the characteristic distance of variation of this per?turbation in the direction of the crack front be small compared to all other characteristic dimensions of the problem, and first of all the thickness of the plates. This