Fatigue life analysis of a fixed-wing UAV rear fuselage based on topology optimisation

To achieve the lightweight design of the fixed-wing UAV fuselage and enhance its performance and load-carrying capacity, this paper focuses on the rear fuselage of a fixed-wing UAV for structural optimization. Initially, the topology optimization method is employed to improve material utilization and reduce structural weight. To ensure the accuracy of the optimization results, models with volume constraints of 30 percent and 40 percent are compared and analysed under multiple loading conditions. The optimal structural design for the rear fuselage of the fixed-wing UAV is then determined using two post-processing methods, encapsulation and reconstruction. This final design results in a weight reduction of 24.9 percent. Additionally, topology optimization significantly influences the stress distribution of the structure, making fatigue life analysis essential to ensure the long-term reliability of the lightweight design under cyclic loading.