两端固定输流管道的参数共振实验

将非接触式测振方法引入到输流管道的参数共振问题的实验研究。首先，通过激光测振技术获取了实验管道中部在脉动流激励下的振动信息；其次，通过确定管道振动频谱图中1/2倍频出现和消失时对应的激励频率，并在多组测试结果的基础上拟合出了管道第一振型1/2次谐波参数共振区域，且实验结果与利用平均法计算得到的理论结果定性一致;最后，对实验结果的误差成因进行了较深入地分析。得到如下结论：在一定平均流速下，两端固定管道在适当脉动幅值和脉动频率下可以发生参数共振现象，且参数共振区域的位置与流速关系较大；管道实际发生参数共振的范围要大于理论计算结果，这可能与选用平均法进行理论计算有关。

Experimental Study on Parametric Resonance of Pipe Conveying Fluid Based on Laser Vibration Measurement Technique

The experimental method of non-contact vibration measurement is applied to investigate the parametric resonance of a clamped-clamped pipe conveying fluid. A laser vibration measurement is used to obtain vibration information of the middle part of the pipe excited by a pulsating flow. It is very important to find out the corresponding exciting frequency when the 1/2 frequency appears and disappears in the spectrum graph of pipe vibration. Then, based on the results of many experiments, the regions of the 1/2 sub-harmonic parametric resonance of the first mode shape are fitted, which are qualitatively consistent with the theoretical results calculated by the averaging method. The conclusions obtained show that at a certain flow velocity, the phenomena of parametric resonance can occur with the proper pulsating amplitude and frequency, and the position of parametric resonance regions are closely related to flow velocity. It is also concluded that the actual region of the parametric resonance is larger than the theoretical one, which may be relevant to the results calculated by the method of averaging. In addition, some analysis on experimental errors is given.