Structural And Hydroelastic Integrated Optimization Design Of Composite Propeller

With the deepening of ocean exploration and resource development,the marine environment faced by marine crafts becomes more complicated,which puts higher demands on the design of marine aircraft propellers.The wide application of composite materials and optimization methods in marine vehicles provides new possibilities and directions for the improvement of the overall performance of propellers.In order to design a composite propeller with higher comprehensive performance,this paper proposes a composite propeller structure and hydroelastic integrated optimization design method.The method considers the influence of structural and shape parameters on the propulsion performance and vibration performance of the composite propeller.By using the accurate prediction ability of surrogate model,it avoids multiple times of fluid-structure interaction calculation during the optimization design process,decreasing the demanding of computational time and resources significantly.During the research,the following achievements have been made.(1)The shape and structure parameterization model of composite propeller were established respectively.In order to enhance the reliability of the design,the accuracy of the modeling and manufacture,and the controllability of the optimization,the main parameters of the composite propeller are splined by the non-uniform B-spline method.The method not only reduces the number of shape design variables significantly,but also improves the smoothness and parameter controllability of the propeller shape.The layup method for highly twisted blades is simplified,and the finite element model of composite propeller blades is established with a laminating solid element,which ensures the high efficiency and automation of FEM modeling.(2)The hydro-elastic numerical method of composite propeller is established.Besides,the influences of grid,turbulence model and added mass effect are discussed.The reliability of the method is verified by engineering examples.The fluid-solid coupling method based on viscous flow and finite element is studied.The method considers the fluid viscosity and makes the hydrodynamic load prediction of the propeller more realistic.When solving the hydro-elastic unsteady response,it can be more perfect considering the effects of unsteady pressure fluctuations caused by turbulent pressure fluctuations,flow separation,vortex dissipation,etc.In order to enhance the reliability of the numerical method,the uncertainty of the abovementioned fluid-structure interaction method is analyzed from the aspects of grid independence,turbulence model uncertainty and added mass effect.In addition,the robustness setting of the composite propeller numerical method is proposed.(3)A Radial Basis Functions Multi-objective Optimization algorithm(RBFMO)is proposed,and a composite layup optimization design model is established with the consideration of vibration performance.Aiming at the expensive black-box problem,the radial basis function is used to establish the surrogate model.Based on which,the multi-objective genetic algorithm is used to optimize multiple targets at the same time.In addition,by adding new samples with a selection criterion and updating the RBF model in each iteration process,the prediction accuracy of the RBF model is further enhanced.Compared with the traditional optimization design method,the method has the advantage of avoiding multiple calls to the expensive fluid-structure interaction calculation in the optimization design,saving a lot of computing resources and calculation time.In addition to the use of mathematical examples to verify the RBFMO method,the multi-objective optimization design problem of composite layup considering vibration performance is optimized by RBFMO,and good optimization design results are obtained.(4)Based on the RBFMO method,the multi-objective optimization design model of composite propeller structure and hydroelasticity is established.The feasibility of the optimization design model is verified by engineering examples,and the optimization design automation process frame is realized based on the modular design idea.From the two perspectives of energy saving and vibration and noise reduction,structural vibration and propulsion performance under hydro-elasticity are targeted together.By establishing a parameter space with integrated structure and shape,the joint effects of the ply orientation and shape parameters on the propulsion and vibration performance are considered.Adopting the modular design idea,the optimization design automation process frame is built,and the problems of fault tolerance,storage,data structure and program execution efficiency are considered,and a stable,efficient and automated design process is generated.The feasibility of the integrated design method is verified by concrete engineering examples,and good design results are obtained.