Fan blades are prone to failures due to dynamic loads and their optimal design ensures the stability of aircraft engines. Compared with the shape and parameter optimization, topology optimization design has a larger design space and frequency adjustment range. However, fan blades are limited by performance requirements such as aerodynamics and load-bearing, and are often designed as hollow structures with fixed main path of load transfer. The existing fan blade design methods impose strict requirements on the construction of frequency topology optimization design space. This paper constructs a frequency topology optimization method of fan blades that considers both stress stiffening and spin softening. The effect of element pseudo density on stress stiffness matrix and spin softening matrix is taken into consideration. A local structural topology optimization method based on the initial path of load transfer is proposed, and a casting constraint method was used to achieve small amplitude frequency control without changing the blade basic structure through erosion and dilation. This paper also constructs the topology optimization formulations of the fundamental frequency maximization, the frequency gap maximization and frequency avoidance constraint. A simple plate example and a hollow fan blade example are used to verify the effectiveness of the optimization method.
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Xu et al. (2024) studied this question.