Dynamic Buckling Of Ship Structures Subjected To Solid-fluid Impact

Buckling is one kind of important failure modes of ship structures, which deserves notice especially when slamming is involved. Ship structures always buckle on the following two occasions. One is the buckling of local structures when subjected to compression caused by slamming directly. The other one is the possible buckling of ship structures under total stresses when ship hull flutters.So far, most of the researches on ship structural buckling are made by assuming that the loads acted on the ship are static. However, nearly every kind of load the ship encountered during its life is dynamic in nature, so it is more rational to discuss ship structural stability based on dynamic buckling theories.Static buckling is up to the value of acting load, while dynamic buckling depends not only on the value of loads, but also on some other factors, such as the frequency and the duration of loading, the initial imperfections and so on.Based on the basic equations of dynamic buckling, perturbation Method and Galerkin Method are adopted to analyze the dynamic elastic buckling of beam and sheet plate subjected to solid-fluid impact respectively, and computer codes are formed to do numerical analysis. A simplified method is then proposed to solve the elastic-plastic buckling of beam based on the related papers. The results show this simplified method is simple and practical enough to analyze dynamic elastic-plastic buckling of beam.When the B-R criterion of buckling is applied, the maximum displacement is evaluated at every load-step of different peak values of impacts, then a characteristic curve of dynamic buckling is plotted based on the maximum displacement, from the curve a dynamic buckling load is determined. In this paper, the influences of initial geometric imperfections, as well as the duration of loading on the dynamic buckling loads, are investigated and finally some useful conclusions are reached.