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Session: Poster session & drinks
Session starts: Tuesday 18 June, 18:00
Presentation starts: 18:01
Room: Room 1.1

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Zijian Zhu ()
Ying Bi ()
Chen Zhu ()
Zhuolin Ying ()
Jian Zhang ()

Abstract:
Unmanned multi-body aircraft (MBA) represents an innovative aircraft configuration, wherein multiple aircrafts are interconnected at the wingtip. It has substantial applications in increasing aspect ratio, optimizing aeroelasticity characteristics, and mitigating takeoff and landing challenges. However, existing studies on MBA predominantly focus on the rigid-body level, overlooking the geometrical nonlinearities stemming from elastic deformation and the concentrated nonlinearities occurring at connections during flight. This paper centers around the configuration of MBA, utilizing a substructure method and modal reduction technique to establish a reduced-order nonlinear structural model. Additionally, describing function method is employed to formulate its nonlinear aerodynamic force model. The Lagrangian equation is then utilized to couple the nonlinear structural equation with the aerodynamic equation, resulting in an explicit dynamic expression for the high-dimensional aeroelastic system encompassing geometric and concentrated nonlinearities. Numerical simulation is used to Conduct parameter analysis and mechanism exploration based on the established aeroelastic system equations, which reveals correlations and impact mechanisms of various nonlinear factors under the MBA configuration, particularly affecting dynamic phenomena such as limit cycles and chaos. The findings suggest that both concentrated nonlinearities and geometrical nonlinearities significantly contribute to the system's bifurcations, limit cycles, and other dynamic responses under the MBA configuration. Specifically, when the number of joined aircraft is limited, concentrated nonlinearity assumes a dominant role, whereas with an increased number of joined aircraft, geometric nonlinearity takes precedence. Furthermore, adjustments to the number of connected aircrafts and model parameters at the connection point unveil the substantial influence of both types of nonlinear factors on the overall flutter characteristics of the system. This study delves into the vibrational characteristics and nonlinear dynamic behavior of unmanned MBA, providing a reference analysis that contributes to the development of this configuration.