Research On Remote Monitoring System Of Health Status Of Miter Gate

The shiplock of Gezhouba in the Three Gorges has taken on an important navigation task since it was opened to traffic in the last century.Its operation safety concerns the navigation function of the middle and upper reaches of the Yangtze River.In the complex water area,the miter gate of ship lock is frequently opened and closed in the complex water area,and it works under the condition of heavy load and low speed for a long time,which is affected by many vibration sources.Both sides of the door body are affected by water pressure on both sides,dynamic water load on one side,surge,as well as jamming during opening and closing of the door body.At the same time,in the working process of the gate body,each structure of the miter gate system of the lock will be subject to different degrees of stress with different working conditions,resulting in stress concentration phenomenon,and then causing damage to each structure.The damage of miter gate caused by the above reasons is not easy to be found in the daily navigation situation,resulting in navigation safety risks.The remote monitoring system of health status of miter gate can monitor the health status of every structure in the daily working state of miter gate in real time.When there is a risk of resonance of miter gate body and the stress of every structure exceeds the threshold value of normal range,an early warning signal will be sent out in time to remind the staff to take corresponding measures to prevent more serious damage.In this paper,based on the original remote monitoring system of the health status of the miter gate,the health monitoring of the miter gate is further studied.The modeling of the structure of the miter gate system is further refined.The appropriate signal processing method is adopted to process the measured vibration signal.The vibration state of the door body under various working conditions is analyzed to determine whether there is resonance risk of the door body.It provides reference for the daily monitoring of the door body,processes the stress signal and analyzes the strain of the main structure of the door body in the working process.The main work includes:(1)The three-dimensional model of miter gate is built according to its structure,and the modal analysis and transient analysis are carried out by ANSYS software.Through modal analysis,the multi-step natural frequency of the miter gate is obtained,which provides theoretical basis for judging whether there is resonance risk of the miter gate.Get the cloud diagram of each vibration mode,verify the correctness of the position of the collected vibration signal sensor,analyze the transient structural stress of the a-bar structure of the door body,get the cloud diagram of the door body stress and the maximum limit stress value,provide the comparative basis for the later stress analysis,and verify the correctness of the position of the collected stress signal sensor.(2)Singular value decomposition and Hilbert Huang transform are applied to the remote health monitoring system of miter gate.In this paper,the method of singular value noise reduction combined with Teager energy operator is used to process the measured vibration signal,and the energy spectrum of different working conditions in different periods is obtained.The vibration status of the door body is analyzed,and the risk of damage is monitored according to the analysis results.According to the nonstationarity and randomness of vibration signal,Hilbert Huang transform is used to get the Hilbert spectrum and marginal spectrum which reflect the time-frequency characteristics of vibration signal.The amplitude and frequency information obtained are compared with the characteristic frequencies obtained from modal analysis of the miter gate,the vibration conditions and reasons of the gate body under different working conditions are discussed,and the resonance of the miter gate body under various working conditions is predicted.Effective and feasible vibration signal analysis and monitoring methods are sorted out.(3)The door structure is regarded as a cantilever beam structure and the characteristics of the door structure are analyzed.The measured stress data of the a-bar structure of the door body are processed by the combination of singular value decomposition and noise reduction and probability density function fitting.Based on the results of the processing and the transient analysis,the health analysis of the related structures of the a-bar and the door body is carried out,and a general method for the stress signal analysis of other structures of the miter gate is given.