Study On Corrosion Acoustic Emission Signals Based On Fractal Methods

Acoustic emission detection technology is a common method to detect the corrosion ofthe oil tank bottom. The vast majority of oil leakage accidents are caused by corruption, so forthe detection of oil tank corrosion, each country and oil exploitation and transportationcompany has paid special attention to it. The fractal method is a new analysis method. In ashort period of time, this method has been applied by researchers all around the world in theactual detection. To solve the problem of corrosion detection, this paper explores therelationship between fractal dimension and steel corrosion.Two aspects of work have been carried out based on the theoretical and experimentalresearch: testing the extract effect of acoustic emission by fast independent componentanalysis（Fast ICA）and the relationship between fractal dimension and steel corrosion.Because fractal dimension is affected large by noise characteristics, Fast ICA has beenadopted to extract and denoise the acoustic emission signals after comparing all kinds ofacoustic emission signal analysis methods. A galvanic corrosion experiment has between analuminum plate and a steel plate has been designed. Through comparing the correspondingrelationship between the fractal dimension before and after denoising and the number ofacoustic emission events, the ability of pretreatment could be tested.In order to explore the relationship of fractal dimension and corrosion, an experiment ofsteel corrosion in different corrosion rate has been designed. In order to judge whether fractaldimension can characterize the corrosion state, observe whether there is a relationship betweenfractal dimention and corrosion after obtaining the fractal dimensions of filtered signals.Through the theoretical and experimental study above, the following conclusions couldbe drawed: Fast ICAcan extract and denoise the acoustic emission signals well; there is also agood relationship between fractal dimension and steel corrosion; and it’s feasible to use fractaldimension to characterize the corrosion state, otherwise shows the feasibility and effectivenessof application with fractal fault diagnosis application in tank bottom corrosion detection.