Research Of Vibration Signal Analysis Methods Based On Ship Lock Miter Gate

As one of the important buildings of the water conservancy hub,the large-sized shiplock miter gate plays an important role in shipping channel of many hydropower stations.Because of its long-term work under conditions oflow speed and heavy load,it is affected by complicated environmental factors such as wind and waves,moving water load,hoist traction and other non-stationary vibration during the operation.If the vibration frequency is close to the natural frequency,thatwill cause resonance.When the amplitude is too large,it will bring structural damage to the door,make a direct threat to the normal operation safety of the lock and sailing vessels upstream and downstream.The subject systematically processes and analyzes the non-stationary time-varying vibration signals during the operation of the miter gate,and extracts the operation characteristic information of the structures from the vibration signals to provide theoretical guidance for the detection and diagnosis of the operation status of the miter gate.In this paper,the miter gate of No.3 Shiplock in Gezhouba Dam is taken as the research object,the structural analysis and working status analysis are carried out,and the modal analysis is carried out by means of the finite element analysis software.The vibration signal acquisition system is set up and the vibration data are processed to eliminate noise and interference,the vibration signal is analyzed in time domain and time-frequency jointdomain,the following research results have been achieved:(1)The structure,work status and vibration signal of the miter gate are systematically analyzed.The miter gate is modeled three-dimensionally by the finite element analysis software ANSYS.The natural frequency and vibration mode got from the reasult provides a theoretical basis for the analysis of the vibration signal of the miter gate.(2)The software and hardware modules of the vibration signal acquisition system of No.3 miter gate of Gezhouba are designed and constructed,the layout of sensors is determined,the software system of PC based on labview is programmed,and the vibration data of the shiplock miter gate is collected,giving a effective miter gate vibration signal acquisition method.(3)The current mainstream vibration signal processing methods to eliminate the trend term and noise of the measured vibration signal are used,the impact of external interference on the real vibration signal is reduced,and the denoise performances of various methods are compared.Time-domain parameter analysis of vibration data is carried out and the time-frequency analysis of signals is carried out by using short-time Fourier transform,wavelet transform and Hilbert-Huang transform.The time-domain parameters and the changes of time-frequency distribution are analyzed and interpreted when the shiplock is opened and closed.The research shows that the operating status of miter gate is in safe range,and the detection and diagnosis method of miter gate based on vibration signal analysis is feasible and effective.