Global buckling and post-buckling of web-core sandwich and stiffened panels: sensitivity to general corrosion

Abstract

Corrosion can lead to reduction of structural stiffness and strength. This paper investigates the influence of a reduction in the thickness of the plates as a result of general corrosion on sandwich panel buckling load and onset of plasticity. The results are compared to the stiffened panel of the same in-plane and bending stiffness. Current guidelines for corrosion protection threat these two structures equally. Load-shortening curves are obtained with the finite element method, with the kinematics being represented using two approaches: (1) equivalent single-layer with first-order shear deformation theory, and (2) a three-dimensional model of the actual geometry of the structure, modeled using shell and connector elements. The former is also used to identify the influence of corrosion on the stiffness coefficients and, consequently, the buckling load, also via analytical equation. The decrease of the buckling load is found higher in sandwich panel than in stiffened panel. The reduction is especially high in the case of the diffusion of moisture (water) into the core. The reason for the higher sensitivity of sandwich panel is a larger reduction of transverse shear stiffness opposite to the stiffener direction due to corrosion.