Chen Zhu, Ying Bi, Zijian Zhu, Zhuolin Ying, Xiaoping Ma
DOI Number: N/A
Conference number: IFASD-2024-037
For the unmanned multi-body aircraft (MBA), free plays are commonly found at the flexible hinges between adjacent flight units, and its nonlinear characteristics will result in the
deviation of aircraft aeroelastic stability boundary, so it is necessary to carry out the research that takes into account the free-play nonlinearity in the context of aeroelastic response analysis. The research focuses on the free play in the rotation direction at the wingtip of an unmanned multi-body aircraft. Based on the fictitious mass method, an appropriate fictitious mass is selected at a suitable position, and the modal shape is linearized to establish a unified modal array capable of expressing deformations across the entire response spectrum. Besides, rational function fitting is used to convert the unsteady aerodynamic forces in the frequency domain to the time domain, and the limit cycle response characteristics corresponding to different free-play parameters are analyzed. The results show that when there is a free play between the wings of an unmanned
multi-body aircraft, nonlinear limit cycle oscillations occur within a specific region below the linear flutter threshold, and the parameters defining these free plays have a notable impact on the amplitude of these limit cycle oscillations and the speed at which divergence occurs.