Dynamic Analysis and Structural Reinforcement Optimization Design of Catapult-Launched Blended-Wing-Body UAVs

Owing to its superior aerodynamic efficiency and structural lightweighting potential, the blended-wing-body (BWB) layout has emerged as a promising configuration for next-generation unmanned aerial vehicles. However, the inherent aerodynamic deficiencies of the BWB configuration (e.g., poor low-speed takeoff and landing performance and low control efficiency) necessitate the adoption of catapult launch and recovery modes. In this paper, dynamic analysis and structural optimization are conducted for two extreme operating conditions of BWB UAVs, namely catapult takeoff and arrested landing. Full-airframe and landing gear finite element models are established, and transient dynamic simulations corresponding to catapult takeoff and arrested-landing processes are performed. The results indicate that under the catapult takeoff condition, the upper attachment fitting of the nose landing gear (NLG) serves as the primary stress bottleneck of the structure. Reinforcement measures, including bolt-hole enlargement, additional stiffeners, and dual-path diagonal struts, significantly improve the factors of safety of all critical load-transfer components. Under the arrested-landing condition, the installation of a rear-fuselage diagonal beam reduces the peak stress of the arresting hook by 19.1%. Furthermore, taking the thickness of the wing-fuselage connecting bulkhead as the design variable, a global Adaptive Simulated Annealing algorithm is adopted for lightweight structural design. After optimization, the structure fully meets the strength requirements while achieving an additional mass reduction of 4.735 kg. This paper provides effective analytical methods and data support for the adaptability design of BWB UAVs applicable to catapult takeoff and landing.