大型环形桁架天线间隙铰径向动刚度的理论与实验研究

Analysis and experiment on dynamic stiffness of clearance hinge in large circular truss antenna

大型环形桁架天线结构由大量的杆件及铰链构成,环形桁架为天线结构的骨架,为天线反射型面的形成提供可靠的支撑.由于结构中存在大量的铰链,在制造及装配等过程中铰链的间隙不可避免,而铰链的动刚度系数对铰链的动力学特性有着重要影响,因此有必要对铰链的动刚度进行研究.本文对大型可展空间环形桁架天线结构间隙铰链的动刚度问题进行了理论与实验分析.建立了铰链动刚度的模型,分析了外激励、铰链间隙及铰链振动幅值对动刚度系数的影响.结果表明,间隙对动刚度系数的影响较为显著,随着间隙的增大,铰链的动刚度系数将会降低.同时,通过实验分析,验证了理论模型的正确性.

Large space structures（LSS） composed of trusses,cables and meshes deployed on orbit,serves as the large antenna for different space missions.Deployable structures which are employed as large space supporting structures of space-borne antennas are widely used in earth observation space missions due to their large stiffness,small folding volume,light weight and easy extensibility.The dynamic research on deployable structures is great importance for the design,analysis,and capacity improvement of such structures.Each LSS contains many joints to combine the substructures,which contain clearance inevitably.The existence of the clearance causes the complicated dynamic characteristics of the LSS.It is necessary to estimate the influence of clearance on the structure.Hinge stiffness is an important factor in determining the dynamic characteristics of articulated structure,this paper will analyze the dynamic characteristics of radial connection part of the plane rotary hinge on large space deployable circular truss antenna structure,the radial kinetic model of hinges is established,the influence of hinge clearance,external excitation and displacement amplitude are discussed.The results indicate that the effect of clearance on the dynamic stiffness of the hinge is significant.On the exciting frequency and natural frequency in the hinge,when the ratio of radial vibration amplitude and the hinge clearance is constant,dynamic stiffness coefficient with the increase of external excitation is reduced.Dynamic stiffness coefficient with the frequency increases with increasing hinge.On the gap size and the hinge vibration amplitude,fixed frequency ratio,with the increase of the gap,the dynamic stiffness coefficient has a decreasing trend with the increase of the amplitude of the hinge,and with the decrease of the gap,the dynamic change of stiffness coefficient is not obvious,when the gap becomes larger,the dynamic stiffness coefficient increases significantly.When the clearance increases,the dynamic stiffness coefficient decreases.The validity of the theoretical calculation is verified by experiments.