DISAPPEARING FIRST-DERIVATIVE OF WEIGHT-FUNCTIONS

Weight functions are very often determined using the Petroski-Achenbac h procedure with some additional conditions. Besides the near-tip disp lacement field and the condition of self-consistence used in the origi nal procedure conditions regarding displacements and their derivatives were applied. Recently, the vanishing first derivative of the weight function has been proposed as such a condition. This condition, expect ed from some numerical results and fit relations, can be proved analyt ically, which will be demonstrated for the edge-cracked half-space and for the infinitely long double edge-cracked plate. (C) 1997 Elsevier Science Ltd.