Design Optimization Of Stiffened Plate-Shell Structures For Buckling Performance

The stiffened plate-shell structure is the main load carrying component in aerospace equipment,and buckling instability is one of its main failure modes.The research on the design optimization of stiffened plate and shell structures can not only meet the load demand but also realize weight reduction,or improve the mechanical performance of stiffened structures without weight gain has important research significance.In this thesis,the design optimization of stiffener layout,section type and size of stiffened plate-shell structure is carried out,for the structural buckling load performance improvement.The relationship between structural weight and buckling load capacity in the optimization design is explored.The main research contents are as follows:1.Topology optimization design of stiffeners is carried out layout based on SIMP(Solid Isotropic Material with Penalization).The aggregate function is used to construct the objective function.The distribution of stiffeners is limited by manufacturing constraints and maximum size constraints,and the compliance constraint function is added to ensure the overall stiffness of the structure.The design optimization model of structural layout is established.In order to improve the optimization efficiency,patch design variables are introduced,and the adjoint method and direct method are used to solve the sensitivity of objective function and constraint function.The MMA(Method of Moving Asymptotes)is used to solve the optimization problem,and the optimization convergence conditions are given.2.Based on the results of layout design optimization,and by combining ISIGHT and ANSYS software,the section type and size design optimization of stiffeners are studied.The influences of compliance constraint and maximum size constraint function on the layout optimization of stiffeners are investigated for the examples including rectangular plate and semi-truncated cone tube structure.The section type and size optimization design of traditional stiffened plate and semi-truncated cone stiffened tube structure are carried out.The optimization results are compared with the stiffened plate and the semi-truncated cone tube structure obtained by the optimization method in this thesis,and the effectiveness of the method is verified.3.Buckling test analysis of optimized stiffened plate and traditional stiffened plate structures is conducted.The buckling tests of optimized stiffened plate and traditional stiffened plate structures are compared.The relative error between the numerical simulation results and the testing results of the buckling load of the stiffened plate structure is explored.4.Quantitative analysis of structural weight and buckling load capacity is investigated.The relationship between volume fraction and buckling load capacity in the layout optimization of stiffened plates is explored,and the relationship between structural weight and buckling load capacity in the optimization design of stiffened cylindrical structures is also analyzed,which provided reference for designers to quickly determine the relationship between the weight and the buckling load capacity in the initial design stage.