Plate buckling

Abstract

In the report the plate buckling verification for stiffened plates subjected to combinations of biaxial in-plane normal stress, in-plane shear stress and out-of-plane loads is performed based on Eurocodes and relevant literature. A normative panel is selected from the structure to go through the calculations step-by-step. As not much literature or information is available for the combination of in-plane stress and out-of-plane load, the main objective is to develop a reliable verification analysis for this load combination.

It was found that by combining the reduced stress method as given in EN-1993-1-5 and the simplified design method as given in EN-1993-1-7 (section 5.2.3.4) for the combination of in-plane stress and out-of-plane load, a verification is possible.

The obtained results were compared to the unity checks given by another design code (DNV-RP-C201) that has a validated design approach for this load combination for stiffened plates. The results showed large similarities in unity checks found for plates subjected to longitudinal in-plane normal stress and out-of-plane loads. In cases with high values of shear stress and for large plate thicknesses, the results for the unity check for out-of-plane loads showed less similarity.

It was recommended to perform the verification of panels subjected a combination of in-plane longitudinal normal stress, in-plane shear stress and out-of-plane loads according to the standard verification analysis given in EN-1993-1-5 (reduced stress method) and EN-1993-1-7 (simplified design method, section 5.2.3.4). For plates subjected to combinations of biaxial in-plane normal stress, in-plane shear stress and out of plane loads, it is recommended to verify the stiffeners according to EN-1993-1-5 section 9, and to check the local buckling according to the reduced stress method, as the local buckling should be normative in case the stiffeners comply with section EN-1993-1-5 section 9.