Hierarchical optimization of the composite blade of a stratospheric airship propeller based on genetic algorithm

High-altitude propellers equipped with solar energy systems are widely adopted in stratospheric airships because of their light weight, excellent mechanical performance, and high efficiency. To optimize the composite laminated structure of the blade, a hierarchical optimization method based on genetic algorithm is carried out. Global and local layers are combined according to the structural and loading properties of the blade, and each partitioned region in the local layer is optimized independently. Combined with the finite element method, a subprogram based on the classical lamination theory is developed to simulate the stiffness matrix of the blade and obtain the deflection, weight, etc. as objects. The restricted condition, whether the structure has failed, is determined by the Tsai-Wu criterion. In addition, multiple tasks are delivered and read simultaneously by a specific program for the sake of improving computation efficiency. After verification with a case study, the stacking sequence and thickness of the blade of a stratospheric airship propeller is optimized and an ideal result is obtained.