旋转叶盘的非接触激光多普勒定点跟踪测试与振动分析

提出了一种旋转叶盘的非接触激光定点跟踪测振方法,以研究叶盘结构在旋转状态下的振动特性。通过控制扫描系统中x、y振镜的偏转实现对叶盘上任意定点的跟踪测试,同时搭建了旋转跟踪试验测试系统,以16叶片旋转叶盘的同步跟踪测试为例,对激光跟踪测试方法进行验证。通过对旋转叶盘定点跟踪测试得到的时域振动信号进行滤波处理和频谱分析,获得了旋转状态下叶盘的叶片前3阶固有频率对应的不同节径的模态族频率。结果显示:激光对旋转叶盘上一点的跟踪测试数据中,可以提取出整个叶盘的振动频率特性。对比不同转速下旋转叶盘的有限元仿真计算与跟踪测试结果,两者振型具有很好的一致性，且频差在5%以内,验证了该激光跟踪测量方法的可行性和有效性。为航空发动机等旋转机械运行状态下的振动测试提供了一种有效的技术手段。 

Measurement and vibration analysis of rotating bladed disk with non-contact fixed point tracking-laser Doppler vibrometry

A non-contact measurement method of laser tracking fixed point for the vibration of rotating bladed disk was proposed to study the vibration characteristics of rotor structures in rotating state. Any point on the bladed disk can be tracked by controlling the deflection angles of x and y galvanometer mirrors in the scanning system. Meanwhile, a rotation tracking measurement system was set up and the synchronous tracking measurement of a rotating 16-blade disk was taken as an example to verify feasibility of the tracking method. By filtering the output of laser Doppler vibrometry and Fourier transform, the natural frequencies of the first 3 families of modes of the bladed disk in the rotating state were derived from the vibration signal, showing that the modal characteristics of the whole rotating bladed disk can be extracted from the frequency spectrum of laser tracking at a point. Comparing the results of the rotating disk measured at different rotating speeds with those derived from finite element model, the mode shapes had good consistency and the relative error of natural frequencies was within 5%. The feasibility and effectiveness of the laser tracking measurement method was validated, providing an effective technology for dynamic test of rotating machinery such as aeroengine.