The Time-frequency Analysis Of Tank Bottom Corrosion Acoustic Emission Signal

Acoustic emission testing technology is a kind of nondestructive testing, which isused for vertical atmospheric storage tank bottom corrosion detection. Acoustic emissiontesting technology doesn’t open cans, more convenient, more economy. Those aspects aredifferent from the traditional storage tank bottom testing. This paper aims at the corrosionacoustic emission signal generation, corrosion signal denoising, corrosion acousticemission test.Corrosion mechanism of acoustic emission signal and its conditions arecomprehensively analysed. With PCI-2acoustic emission acquisition system and theallocation of10%FeCl₃·6H₂O, it researched the way of the tank bottom to prodce acousticemission. In the process, the signal of steel corrosion acoustic emission is studied. As moredeeply corrode, as more corrosion points and corrosion signal appear. It is showed by theexperimental analysis.At present, there are four main ways to reducing the noise of the tank bottomcorrosion acoustic emission signal, classic spectrum analysis, the modern spectral analysis,wavelet analysis and pattern recognition methods. However, discrete cosine transform isthe hot spot of the corrosion acoustic emission signal noise reduction processing research.This paper mainly studies the tank bottom corrosion acoustic emission signalcharacteristics, classic spectrum analysis, the modern spectral analysis, wavelet analysis,pattern recognition method of characteristics. It is very important that the characteristicsand calculation process of the discrete cosine transform. According to the tank bottomcorrosion acoustic emission signal characteristics, it put forward short time shapedimension reinforcement method. This paper specially research the short time shapedimension method’s background, application principle and applicable condition. And ithave many advantages for researching the time-frequency analysis of the tank bottomcorrosion acoustic emission signal. Through the simulation of the actual tank bottomcorrosion occurrence conditions, it can obtain the acoustic emission. The short time shapedimension reinforcement method and discrete Fourier transform method for acoustic emission signal with noise will compare of several methods, and get the best processingmethod.