基于递归理论的泵站压力管道运行状态监测

针对不利因素导致的管道运行异常问题，提出一种基于递归理论的泵站管道运行状态监测方法。首先，通过振动传感器提取压力管道关键部位的实测信息，并将同一位置不同方向的数据信息进行融合，得到一组反映结构整体动力特性的综合数据；其次，利用伪近临法与互信息法分别选取相空间重构参数m和τ；最后，绘制并计算代表管道动力特性的递归图及递归量化指标。将该方法应用于景泰川工程二期七泵站管道运行监测，通过设置不同的运行工况进行验证，结果表明：机组开关瞬间与稳定运行工况下，管道结构振动信号的递归图呈现不同模式，递归量化指标-确定性、对角线平均长度L、递归率及递归熵也呈现明显差异，能有效区分管道振动状态。该方法为压力管道的无损动态监测提供了新思路。

Monitoring the Operating Condition of Pipeline of Pumping Stations Based on Recurrence Theory

It is important to accurately identify structural modal parameters for structural health monitoring and damage identification. In this paper, a new structural modal parameter identification approach is developed based on multiple signal classification algorithm (MUSIC), empirical wavelet transform (EWT) and synchroextracting transform (SET). In the proposed method, the measured vibration signal is decomposed by MUSIC-EWT to obtain a single mode signal. Secondly, SET is used to remove noise from each mono component. Then, the free vibration response of each mono component is obtained using natural excitation technique (NExT). Finally, Hilbert transform (HT) and curve fitting method are used to estimate the natural frequency and the damping ratio. A numerical simulation of a three-story frame structure is employed to validate the effectiveness and robustness of the method. Furthermore, the measured acceleration responses of CITIC Plaza during Typhoon Damrey are analyzed based on the approach. The accuracy of the developed method is further verified by comparing the identified modal parameters of this super-tall building with those determined by some other existing methods.