The structure must be able to contain a fracture while subjected to combined loads typical in a pressurized fuselage. Machined integrally stiffened curved fuselage panels were tested under simulated fuselage loading conditions. Panels contained either a circumferential or longitudinal crack.
Photos show the machined panel and test fixture to evaluate the longitudinal crack case.
The panel has machined stringers and pad-up areas with riveted frames. Panel was precracked under cyclic loading at 8.6 psi to a crack length of 38 . Panel then loaded by increasing pressure. Rapid crack extension occurred at about 9.7 psi and the crack arrested at rivets that attach the frames. Final crack length was approx.