目的 研究预应力杆对大型空间桁架天线固有频率影响,提出采用作动器实时对在轨空间天线低阶固有频率进行调整,主动避免共振现象发生.方法 针对大型空间桁架天线结构有限元模型,采用降温法对桁架杆施加预应力,重点分析预应力大小、预应力杆位置、预应力杆数量对整体结构固有频率的影响.结果 增加预应力大小、合理布置预应力杆位置、增加预应力杆数量能够增加空间桁架天线固有频率的改变率.结论 合理优化空间桁架天线上预应力杆,可实现对在轨运行的空间桁架天线低阶固有频率实时调整,可为空间桁架天线避振设计提供参考.%Objective To study influences of prestressed bar on natural frequency of large space truss antenna and propose to adjust natural frequency of a orbiting antenna to avoid resonance.Methods The finite element model of large space truss antenna was presented and the cooling method was used to apply prestress to the truss bar.The influences of the size of prestressing force,the position of prestressed bar and the number of prestressed bars on the natural frequency of the whole structure were analyzed emphatically.Results Increasing the magnitude of prestress,arranging position of prestressed bars reasonably and increasing the number of prestressed bars could increase the change rate of natural frequencies of space truss antennas.Conclusion Reasonable optimization of prestressed bar on space truss antenna can realize real-time adjustment of low order natural frequency of space truss antenna in orbit,which can provide reference for avoidance of vibration in design of space truss antenna.
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