Singular propagation behavior of cracks in stiffened cylindrical shells

Crack propagation in a 300-mm-long 200-mm-diameter circular cylindrical shells of 1-mm-thick Al alloy, both unstiffened and stiffened with one or two circumferential 22-mm-wide riveted bands of the same material, is investigated experimentally and analytically. Stiffeners are found to have an adverse effect on the fracture strength and burst pressure of the shells, a phenomenon attributed to increased stress-intensity factors associated with the interaction of crack and stiffener. Implications for the design of shell-like structures such as aircraft pressure cabins are indicated.