A topology optimization method of composite laminate considering density change rate constraint

To avoid the problem of alternating layers of different materials in the thickness aspect, a topology optimization method of composite laminate considering density change rate constraint is proposed. This method utilizes the density of a specific layer to constrain the upper limit of density for its neighboring layers, so that the relative density of the upper and lower layers is greater or less than the middle layers. The middle layers of the laminate are one material and the adjacent upper and lower layers are another material. The low-density material in the middle layers is taken as an example, the density of the specified layer in the design space is used to constrain the upper limit of the density of its adjacent layers. The middle layers are limited by the constraint strategy, and the relative density is smaller than that of the two sides. The purpose of replacing the middle layer where is in the design domain with low-density material can be effectively realized. The mathematical model for patch topology optimization of composite laminate considering density change rate constraint is established, and the reasonable space layout of fiber composite and low-density material is obtained by solving. The numerical example of the composite laminate and the wind turbine blade structure show that the optimized two-phase materials distribution follows the corresponding manufacturing constraints, and also reduces the total mass of the structure while ensuring the mechanical properties. And the mass of their structures are reduced while ensuring the mechanical properties. The feasibility and effectiveness of the method are verified.