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文章针对一个典型的卫星桁架结构建立了三自由度运动模型,分别引入间隙非线性和Iwan模型描述了非线性连接结构;利用数值方法研究了系统的频率漂移,讨论了间隙大小、预紧力(重力)、系统阻尼、随机间隙及Iwan模型的参数对频率漂移的影响;对比了两种非线性连接结构下系统频率漂移的特点。研究表明,间隙结合预紧力条件可令结构呈现“硬弹簧-软弹簧”特性的频率漂移,迟滞和间隙两种非线性引起的频漂在幅频曲线上表现出不同的特点。
In this paper, a 3-DOF motion model is built for a typical satellite truss structure. The nonlinear connection structure is introduced by introducing the gap nonlinearity and the Iwan model respectively. The frequency drift of the system is studied numerically. The effects of gap size, Gravity), system damping, stochastic clearance and Iwan model’s parameters on frequency drift. The characteristics of system frequency drift under two kinds of nonlinear connection structures are compared. The research shows that the gap preload condition can cause the structure to exhibit the frequency shift of the “hard spring - soft spring” characteristic. The hysteresis and gap caused by the nonlinearity of the two kinds of frequency drift show different characteristics in the amplitude-frequency curve.