The effect of crack-tip point loads on fracture (Q1584898)

Conclusion: The presence of surface stress on the faces of a straight crack does not produce any change in stress intensity factors (SIF). It may, nevertheless, interact with a SIF-producting load so as to alter the configurational equilibrium condition. Similar effect may be brought about by the placement of point loads at crack tips. In fact, the toughness of a solid is reduced by an amount equal to the applied point force. We discuss these facts in the context of configurational equilibrium or fracture theory.