仪器安装板结构阻尼比识别及振动环境预示研究

Study on damping identification and vibration environment prediction of aircraft instrument board

研究了仪器安装板的结构阻尼识别的两种方法,分别为时域滤波对数衰减法方法和扫频曲线多项式拟合方法。首先,给出了仪器安装板的有限元模型,其中单机仪器使用带转动惯量的质点模拟,并通过MPC法与安装板连接;其次,分别通过时域滤波对数衰减法方法和扫频曲线多项式拟合方法辨识了安装板的阻尼特性;最后,通过模态叠加法预示了该仪器安装板在振动条件下的结构动力学响应,并与振动试验结果进行了对比分析。研究发现,两种阻尼辨识方法得出的结果是一致的,且通过试验辨识的阻尼特性能较好的预示板类结构的动力学响应。

the algorithm for damping identification of the aircraft instrument board is investigated, which include filtering logarithmic decrement method （FLD） and the frequency-sweeping signal polynomial fitting method （FSPF）. Firstly, the FEM model of the instrument board is established, where the instruments are simulated by mass point with rotational inertia, and connect with the board by MPC method. Secondly, the damping property is identified by the FLD method and FSPF method. At last, the dynamic response of the instrument board is calculated with multiform damping, and the prediction is compared with the result of the vibration experiment. According to the research, the damping of the two methods are similar, and the prediction is more closed to the experiment by the using the damp which is derived by the experiment.