3-DIMENSIONAL DYNAMIC PERTURBATION OF A PROPAGATING CRACK

Asymptotic formulae are derived for the perturbations to the stress in tensity factors induced by a small three-dimensional dynamic perturbat ion of a propagating, nominally plane, crack. The crack propagates thr ough an infinite isotropic uniform medium and full account is taken of the equations of elastodynamics. Previous work by the authors treated the case in which the edge of the crack was subject to an in-plane pe rturbation, so that the crack remained plane, but with a wavy edge. Th e present work completes the study, by allowing for out-of-plane pertu rbations. (C) 1997 Elsevier Science Ltd.