An Analysis Method of the Efficiency for a Finite Stringer to Retard Crack Growth

Bonding a finite stringer over a local cracked region in a plate has been testified to be able to retard efficiently the crack growth. It is investigated theoretically in this paper. For the case that a finite stringer is symmetrically bonded over a crack in a plate,an analysis method for calculating the stress intensity factors at the crack tips,the fronts of the internal adhesively bonding region and the ends of the stringer is developed,which can be used to evaluate the efficiency of the stringer for retarding the crack growth. Based onthis,a large numerical results are worked out to show the effects of a stiffness parameter of the stringer and some geometrical characteristic parameters of the problem on the efficiency of the stringer for retarding crack growth. From these numerical calculations it can be seen that the analysis method in this paper is effective and rapid and hence can be conveniently used in the optimum design of the damage tolerance for aerospace structures.