Presented at 44th International SAMPE Symposium: Long Beach, CA, Volume 44, May 23, 1999, pages 2358-2367.
This study presents an experimental investigation of fracture mechanics for isotropic material, aluminum alloy D16AT. The problem of stable crack growth (SCG) has been addressed in this paper. Experimental results are presented for symmetrically stiffened and unstiffened three point bend specimens subjected to different modes, mode I and mixed mode. The stiffeners are doubly bonded to the fatigue pre-cracked specimens parallel to the length at a certain distance behind the crack tip using an adhesive Redux 410 NA. Results concerning load displacement variation, growth of plastic zones, instantaneous crack edge profiles, and tunneling are presented. There is evidence that the whole stable growth can be characterized by the crack opening angle criterion. The stiffening helps to increase both initiation and maximum fracture loads substantially.