On-line Global Acoustic Emission Monitoring Method For Large Storage Tank Floor

On this basis,this paper puts forward that some sensors should be put into the tank interior medium to form an array with the sensors arranged on the tank wall near the tank bottom,so as to increase the area of the tank bottom positioning,and designs an internal detection device to carry a number of underwater sensors from the tank top to the tank interior.The device can be mechanically deployed inside the tank,so that the built-in sensors can form an array for storage.Defect location in tank center area and joint work with external sensors can locate the edge area of tank.Simulated signal reception experiment of bottom plate defect of vertical storage tank is carried out on the basis of this device.The simulation experiment results show that the sensor carried by the internal detection device can receive acoustic emission signals of corrosion and leakage of tank bottom,and the received signal amplitude and intensity are all required.It is higher than the external sensors and can collect low amplitude signals which are difficult to receive by the external sensors,which provides a reasonable basis for the overall monitoring and evaluation of acoustic emission of large storage tanks.On the basis of acoustic emission whole-area monitoring,two new spatial acoustic emission location methods,Geiger location algorithm and three-dimensional overdetermined location algorithm,are proposed in this paper.The time difference between signals arriving at each sensor is calculated by introducing two methods of multiple cross-correlation and all-phase phase difference.At the same time,a comparative experiment of acoustic emission location simulation of tank floor damage process is designed.The results of simulation location test show that the method is effective.The average relative error of the three-dimensional overdetermined positioning method based on all-phase phase phase difference is the smallest,which is suitable for defect location of the whole-area acoustic emission monitoring method for the tank floor.Based on the three-dimensional over-positioning algorithm with all-phase phase difference,a new acoustic emission positioning system,3DNTBPT,is developed and compared with the simulated tank floor defect positioning system with the built-in SAMOS positioning system.The experimental results show that the positioning error of the 3D NTBPT positioning system is lower than that of the SAMOS positioning system,and the positioning points are relatively centralized,which can well reflect the defects.The locationprovides a theoretical basis for safety evaluation of acoustic emission monitoring of large storage tanks.