Research on Residual Strength and Evaluation Methods of Metal Aircraft Stiffened Panel Structures with Perforations

This study investigates the interaction between the skin and stiffeners under tension and the structural failure mechanisms of aluminum alloy stiffened panels after battle damage, employing an integrated approach of experimental testing and numerical simulation. The variation in the residual strength of the stiffened panels with the characteristics of ruptures was explored, and an assessment method for residual strength was proposed based on the net-section failure criterion. The results indicate that the residual strength of the stiffened panels is closely related to the location and size of the rupture. For panels with ruptures of equal area, the residual strength is lowest for those with web damage, followed by those with flange damage, and highest for those with skin damage only. By employing an area-based conversion method, the three-dimensional stiffened panel was simplified to a two-dimensional plate. A stress averaging coefficient was introduced for large eccentric ruptures, while a conversion factor was applied for small eccentric ruptures to modify the residual strength assessment. The results demonstrate high accuracy. This study provides an efficient and precise method for evaluating the residual strength of damaged stiffened panels, offering a theoretical basis for aircraft battle damage repair.