Saturated Impulse Of Marine Structures Under Cabin Explosion

To build ocean power with the times,improve China’s comprehensive maritime power continuously and form a systematic and strategic marine constitution,China’s maritime defense construction needs to follow up and develop at the same time.It is a necessary link of marine defense construction to carry out the research on the safety and impact protection of ship and marine engineering structures,so as to provide the basis for explosion and impact resistance of ship and marine structures.With the improvement of armor piercing weapons,cabin explosion load became the common explosion load currently.This thesis makes a comparative analysis of air explosion and cabin explosion,concerns the saturation impulse which plays an effective role in the dynamic plastic response of ship structure under cabin explosion,and discusses the influence of implosion parameters and type of stiffeners based on saturation impulse on the dynamic plastic response of ship structures under cabin explosion.In order to facilitate practical engineering application,complex load is usually equivalent to simple load to simplify calculation.In this thesis,several load equivalent methods are analyzed,where the saturation equivalent method performs better in the calculation of the dynamic response of the ship structures under cabin explosion,and the application of the method is summarized.The main research contents are as follows:(1)The basic characteristics of explosion wave are studied.A series of empirical formula calculation results and finite element numerical simulation results are compared and analyzed for the three important parameters representing the intensity of explosion wave.The load characteristics of air explosion and cabin implosion are compared through empirical formula calculation and finite element numerical simulation.(2)Based on the study of dynamic plastic response of ship structures under cabin explosion considering saturation impulse,the linear relationship between the dimensionless saturation deflection and the dimensionless saturation impulse at the center point of the cabin plate is obtained,and the relationships between the explosive amount,plate thickness,type of stiffeners and the dimensionless saturation deflection and quasi-static overpressure at the center point of the cabin plate are analyzed and summarized,The influence of type and combination of stiffeners on cabin explosion resistance is determined;(3)The complex cabin explosion load is simplified according to impulse equivalence,and four simplified load models are obtained.The rigid plastic theory derivation and elastic-plastic finite element comparative analysis of these four simplified load models are carried out.The dynamic plastic response of ship structures is basically equal under different equivalent load models with equal impulse;(4)The Youngdahl equivalent method,the whole pulse equivalent method and the saturation equivalent method are applied to the simplified load model obtained from the cabin explosion simplification and the complex cabin explosion load respectively,from which their applicability in cabin explosion is discussed and the conclusion that the saturation equivalent method performs the best is obtained.Furthermore,the application process of saturation equivalent method in cabin explosion is provided.In this thesis,the research on the phenomenon of saturated impulse and the relationship between relevant parameters in cabin explosion,as well as the research on the equivalent method of cabin explosion load,provide a reference for the study of the dynamic plastic response of ship structures under cabin explosion,which is of engineering and academic importance for the anti-explosion and anti-impact design of marine and ocean engineering structures.