Research On Theoretical Prediction Method Of Marine Corrugated Cores Steel Sandwich Plate Structure Response Under Typical Load Model

With the development of ships and marine engineering equipment,the requirements for structural safety,functionality and lightweight of ships are increasingly urgent.Compared with the traditional ship stiffened structure,the steel sandwich plate structure has the advantages of high specific strength,small welding deformation,and excellent protection performance,strong design and so on,which is favored by the ship industry.The navies,classification societies and scientific research institutes of various countries have successively carried out the research work on sandwich plates in various aspects.The superior mechanical properties of steel sandwich plates are attributed to their special structures.Therefore,it is of great significance to study the mechanical characteristics and deformation modes of steel sandwich plates under typical load modes for promoting the large-scale application of steel sandwich plates on ships and improving the design level of ships.Steel U-type corrugated cores sandwich plate for warships construction is taken as the research object.The application areas of steel sandwich plates on ships are analyzed,the main bearing forms are classified and summarized,and finally three typical loads(quasi-static compression load,collision load and bending load)borne by the corrugated steel sandwich plates are determined.By designing and carrying out the test of steel sandwich plate under three typical loads and corresponding numerical calculation,the structural deformation process and deformation characteristics of U-type corrugated cores sandwich plate under three typical loads are analyzed and obtained.Then,the deformation modes of steel sandwich plate structure under three typical loads are proposed,and the theoretical models are established.The theoretical prediction method of ship steel sandwich plate structure under typical loads is studied,and the analytical calculation formula is derived.The main research contents are as follows:(1)The basic principles,analysis ideas and solution process of simplified analytical calculation method are summarized.The main bearing forms of steel sandwich plates in the application areas of ships are sorted out,and the marine steel sandwich plates are decomposed into basic components.Similar hull local components,common damage and deformation modes under typical load modes and theoretical analysis methods based on deformation modes are discussed.(2)The quasi-static compression test and corresponding numerical simulation analysis of U-shaped steel sandwich plate were designed and carried out,and the structural deformation process and load curve under the quasi-static compression load were obtained.The main deformation characteristics and damage deformation mechanism were determined,the rigid-plastic mechanics model was established,and the corresponding theoretical prediction formula was deduced.The results were verified and improved based on the experimental and simulation results.(3)Dropping impact test and corresponding numerical simulation analysis of U-shaped steel sandwich plate model were designed and carried out to analyze the structural deformation characteristics and damage deformation mechanism of U-shaped sandwich plate structure under impact load and to discuss the impact of impact dynamic effect.Then the deformation mode was obtained,the rigid-plastic mechanics model was established,and the analytical calculation formula of the collision force was deduced.The correctness of the analytical calculation method and formula was verified by comparing with the experimental and simulation results.(4)The three-point bending test and the corresponding numerical simulation calculation of the steel sandwich plate and its in-plane connection structure model were designed and carried out.The stress,damage and deformation characteristics and their deformation mechanism of the in-plane connection structure of steel sandwich plate under bending load are analyzed.Then the deformation mode is determined,the rigid-plastic mechanics model is established,and the theoretical calculation formula of the deformation resistance of the structure is deduced.Finally,it is verified and improved based on the test and simulation results.