基于电反馈自激振动的圆柱壳固有频率测量方法

振动按激励类型分为自由振动、强迫振动、自激振动和参数振动。目前固有频率测量的两种方法:敲击法和扫频法分别基于自由振动和强迫振动的原理。提出基于自激振动的原理测量圆柱壳的固有频率与模态的方法。此处的自激振动是基于电信号反馈激励,从而导致圆柱壳的自激振动;而非普遍被研究的摩擦导致的自激振动或线的风激振。将其命名为电反馈自激振动法,通过该方法对一个圆柱不锈钢钢管的模态与响应幅度-激励频率曲线的测量。与敲击法、扫频法和ANSYS仿真分析的结果进行对比,证明了该方法测量固有频率及模态的可行性;并得到自激振动时的振型分布及稳定激振的频率与传感器的位置有关的结论。该方法相比敲击法和扫频法具有测量设备简单、测量快速的优点。

Natural Frequencies Measurement Method Based on Self-exited Vibration of Cylinder

Vibration is classified to free vibration, forced vibration, parametric vibration and self-vibration by the type of stimulation. Knocking method and frequency sweep method are mostly applied to measure natural frequencies, which are based on free vibration and forced vibration. This article rises a method based on self-exited vibration to measure natural vibration frequencies and vibration modes of a cylindrical shell. And the self-excited vibration is induced by electrical signal feedback sitimulation, rather than the widely studied friction-induced self-excited vibration or wind-induced self-excited vibration of a wire. This article names it electronical feedback self-extied vibration method. A stainless steel tube is measured by this method and the other two methods for contrastions, and also the ANSYS Simulation, which prove the feasibility of electronical feedback self-vibration method. Conclusions are made by the study that mode of vibration and frequency of the vibration is decided by the position of the sensor. The method based on self-exited vibration requires simper measurement devices and has higher measurement efficiency contrasting with knocking methed and frequency sweep method.