Stress intensity factors and plastic zones of stiffened panels with multiple collinear cracks

Abstract

Stiffened panel with multiple site cracks has been a great concern in the aviation industry and academia. In this paper, an analytical method for solving the stress intensity factor and strip yield model with coalesced plastic zone is developed based on the superposition principle, displacement compatibility and weight function method. It is then applied to obtain the stress intensity factors and plastic zone sizes for stiffened panels with two and three collinear cracks. The determined stress intensity factors and plastic zone sizes are compared with those from finite element analysis and existing literature. The present method is demonstrated to be accurate and efficient in calculating the stress intensity factor and plastic zone size for residual strength and fatigue crack growth prediction of stiffened panel with multiple site cracks.