Effect of a central dent on the ultimate strength of narrow stiffened panels under axial compression

Abstract

This paper studies the effect of a central dented imperfection on the load carrying capacity of stiffened panels considering the residual stress caused by the indentation, and identifying the type of boundary conditions to adopt for a model to be used in an experimental programme for damaged panels. A quasi-static nonlinear finite element analysis is used to simulate the production of the local dent, followed by an ultimate strength analysis of the stiffened panels under uniaxial compressive load. The structural plastic strain causes the residual stress and the dent, which are included in the ultimate strength analysis of the stiffened panels under compressive load. To prescribe appropriately the boundary conditions for the central span of stiffened panels, two and three spans models are adopted in the FE analyses. The effects of residual stress, geometric range and dent depth on the ultimate strength of the stiffened panels with a central dented imperfection are investigated using nonlinear quasi-static finite-element analysis.