Research On Multi-objective Optimization Design Of Stiffened Cylindrical Shell Structure

The stiffened cylindrical shell structure is a widely used structural system in modern engineering structure.Therefore,the optimization design of the structure in the shipbuild ing industry,aerospace and other fields has attracted people's attention gradually.The opt imization design is beneficial to discover more potential for application of structure,redu ce the cost,improve the structure performance and safety.In this paper,several commonly used optimization algorithms and their principles briefly.The Subproblem Approximation Method and the First-order Optimization Meth od of ANSYS optimization module are studied,and the mathematical principle and op timization process of the two methods are discussed in detail.In this paper,three different stiffened cylindrical shells are designed,and two dim ensional optimization design is carried out under two different conditions.The size opt imization is based on the optimization module of ANSYS software.In the optimizatio n control document,the specific parameter setting,the convergence precision,the curv e fitting method are properly adjusted.The reasonable optimization tool is selected an d the optimal optimization scheme is selected.Based on the Subproblem Approximatio n Method and the First-order Optimization method,the size optimization program for t he stiffened cylindrical shell structure are designed respectively.The topology optimizat ion function of ANSYS is used to finish the natural frequency topology optimization of the three cylindrical shell models mentioned above.The topology optimization prog ram is written in APDL language.The frequency topology optimization is based on th e theory of density-varying method,SCP algorithm is used as the optimization solutio n method.The topology optimization of the stiffened cylindrical shell structure with the objecti ve of the smallest weight is carried out based on the BESO method using the computing software developed by the project group.Because the manufacturability of the optimal t opology is not good,especially when the edges of optimal topology are jagged.Therefor e,this paper proposes a second optimization stage with response surface method to make the connection part more smooth and improve its manufacturability.Finally,The multi-objective optimization design is carried out on the stiffened cylind rical shell structure with the weight and the natural frequency as the target based on the main objective method.The multi-objective optimization strategy and the importance of e ach target are considered,the multi-objective optimization mathematical model is establis hed,and the solution is solved by the Subproblem Approximation Method.