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The general corrosion and local corrosion of Q235 steel were tested by acoustic emission(AE) detecting system under 6%FeCl_3-6H_O solution to effectively detect the corrosion acoustic emission signal from complex background noise.The short-time fractal dimension and discrete fractional cosine transform methods are combined to reduce noise.The input SNR is 0~15 dB while corrosion acoustic emission signals being added with white noise,color noise and pink noise respectively.The results show that the output signal-to-noise ratio is improved by up to 8 dB compared with discrete cosine transform and discrete fractional cosine transform.The above-mentioned noise reduction method is of significance for the identification of corrosion induced acoustic emission signals and the evaluation of the metal remaining life.
The general corrosion and local corrosion of Q235 steel were tested by acoustic emission (AE) detecting system under 6% FeCl_3-6H_O solution to effectively detect the corrosion acoustic emission signal from complex background noise.The short-time fractal dimension and discrete fractional cosine transform methods are combined to reduce noise. The input SNR is 0 to 15 dB while corrosion acoustic emission signals being added with white noise, color noise and pink noise respectively. The results show that the output signal-to-noise ratio is improved by up to 8 dB compared with discrete cosine transform and discrete fractional cosine transform. The above-mentioned noise reduction method is of significance for the identification of corrosion induced acoustic emission signals and the evaluation of the metal remaining life.