基于解析模态分解和希尔伯特变换的模态参数辨识新方法

A new method for modal parameter identification based on analytical modal decomposition and Hilbert transformation

针对航天器结构低频、密频的模态参数辨识问题,提出一种将解析模态分解(AMD)与希尔伯特变换(HT)相结合的模态辨识方法(AMD+HT),根据结构上任意一点的脉冲响应信号,对系统结构的频率和模态阻尼比进行参数识别。以箱型卫星模型为例,分别对固定状态下卫星帆板和卫星整体结构的低阶模态进行模态辨识,并与LMS数据采集系统分析结果和ANSYS有限元仿真结果对比,验证了该方法对低频、密频结构模态辨识的正确性和优越性。

In order to identify modal parameters of spacecraft structures with low frequencies and closely spaced modes, a new identification method based on analytical modal decomposition （AMD） and Hilbert transformation （HT） was proposed. The modal frequencies and modal damping ratios of a structure were obtained with its impulse responses at any point. A satellite model composed of a central rigid body and two panels was taken as a typical example of spacecraft structures. The low-order modal parameters of a single panel and the satellite model under fixed boundary conditions were identified using this method. The comparison between the results obtained with this method and those obtained with tests and other simulation methods showed that the new proposed method is valid, especially, for spaceraft structures with low frequencies and closely spaced modes.