SOME COMPUTATIONAL TOOLS FOR THE ANALYSIS OF THROUGH CRACKS IN STIFFENED FUSELAGE SHELLS

Reliable analytical methods that predict the structural integrity and residual strength of aircraft fuselage structures containing cracks ar e needed to help to understand the behavior of pressurized stiffened s hells with damage, so that it becomes possible to determine the safe l ife of such a shell. Of special importance is the ability to determine under what conditions local failure, once initiated, will propagate. In this paper we shall present a reliable and efficient method for com puting the energy release rate for cracks of varying length in a typic al stiffened metallic fuselage under general loading conditions. The m odels used in the simulation are derived from an extensive analysis of a fuselage barrel section subjected to operational flight loads. Ener gy release rates are computed as a function of the length of the crack , its location, and the crack propagation mode.