Design On Multi-objective Optimization Of Fiber Reinforced Composite Structure

Fiber reinforced composites have been widely used in various industrial fields due to their good properties in many aspects,and have broad application prospects with the gradual maturity of 3D printing technology.Based on the investigation and summary of the domestic and foreign literatures on the topology optimization of fiber reinforced composite structures,this paper finds that the research on the simultaneous optimization of the characterization of fiber angle and topology configuration in the dynamic environment of the material structure is relatively rare.Considering the wide application of fiber reinforced composites in practice,this paper attempts to take minimizing the compliance value and maximizing the fundamental frequency of the structure as the content of multi-objective optimization design to carry out research on related problems.The main work contents are as follows:(1)According to the principle of finite element for global coordinates orthogonal material constitutive matrix obtained under the total stiffness matrix of fiber reinforced composite material structure,in order to structure the compliance value of minimizing goal to establish the optimization model based on SIMP interpolation format,and then the sensitivity of the objective function to the density design variable and the fiber laying Angle variable was derived,and the iterative optimization was performed with the help of MMA algorithm.Some examples is given to verify the effectiveness of the method.(2)Based on the improved SIMP interpolation scheme,the first-order frequency maximization problem of fiber reinforced composite structures is studied to avoid the local modal problem which often appears in the dynamic optimization problem of SIMP method.The sensitivity of the objective function with respect to the two design variables is further derived by solving the structural total stiffness matrix and structural total mass matrix under the improved SIMP interpolation scheme.The classical physical models is selected to verify the effectiveness of the method.(3)An appropriate evaluation function method was selected to establish a multiobjective optimization model,and the sensitivity of the objective function under the corresponding model was deduced respectively.The optimization results of each objective with different weights and the optimization results of structural topology configuration and fiber orientation were respectively solved under the two evaluation methods.Based on the ideal solutions of each objective of the research object obtained in previous work,the decision function was used to obtain the optimal compromise solution.Finally,the optimal result under the weight corresponding to the optimal compromise solution is closer to the ideal solution.The multi-objective optimization design of fiber reinforced composite structure studied in this paper has obtained good results in topology optimization under each objective,which can be used as a reference for the future research work of the material structure under more complex working conditions.