Multi-objective Optimization Study Of Ring-stiffened Circular Cylindrical Shell Of Submarine

Pressure shell structure is a key component of the submarine.It has important implications for the submarine's safety,combat performance and many other aspects.Due to its excellent structural properties,the ring-shaped cylindrical shell has been widely used in the submarine's main structure design.The basic principle of pressure-resistant structural design is the balance of many goals such as strength,stability and weight.That is a typical multi-objective optimization problem.In this paper,the submarine ring-stiffened cylindrical shell is taken as the research object.It aims at the key contents of its multi-objective optimization design process,which attempts to provide reference for the structural design of the ring-stiffened cylindrical shell.Firstly,the influence of structural parameters such as length of cabin section,rib spacing,shell thickness,mid-plane radius and rib model on the strength,stability and free vibration frequency of submarine ring-stiffened cylindrical shell are analyzed.It aims to provide the principle of establishing the submarine ring rib shell optimization model.Secondly,the design variables,objective functions and constraints of each optimization model are analyzed and determined.In order to get the effect of frequency constraint on optimization results,a multi-objective optimization model is established based on the allowances,to fix the problem that the optimization objectives of cylindrical shell are not balanced with the allowable value.In order to further strengthen the relationship between the stress and load,the information entropy theory is applied to the optimal design of cylindrical shell,and a weight-based multi-objective optimization model is established.Thirdly,based on NSGA-?,four kinds of multi-objective optimization model are solved to get the characteristics of each optimization model and the relationship between Pareto solution set.The correlation theory is used to analyze the relationship between the structural parameters and the target attributes of the cylindrical shell.The analysis results are visualized as scatter matrix to obtain the interrelationship of the variables.At last,in order to solve the decision-making problem of the multi-objective optimization,the Pareto solution of all the offspring is determined and sorted by using TOPSIS method and analytic hierarchy process(AHP),eventually obtaining a satisfactorysolution.