基于包絡(luò)Holder指數(shù)的AE信號初至?xí)r刻精確拾取
中國測試李 力， 李 驥
聲發(fā)射（AE）信號初至?xí)r刻精確拾取是聲發(fā)射源定位中的關(guān)鍵問題，該文探討基于連續(xù)小波變換的H?觟lder指數(shù)方法拾取AE信號初至?xí)r刻，為突出信號初至?xí)r刻的奇異性特征，提出對信號包絡(luò)估計的包絡(luò)H?觟lder指數(shù)方法。通過對模擬AE信號和金屬裂紋AE信號應(yīng)用結(jié)果表明：包絡(luò)H?觟lder指數(shù)可以精確提取AE信號的初至?xí)r刻，誤差小于2 μs，能為AE源定位提供一種有效手段。
The identification of the first arrival time of acoustic emission （AE） signal is one of the key problems in AE source location. This paper presented a method of envelope Holder exponent to identify the first arrival time of AE signal. Firstly， the envelope by Hilbert transform was extracted to highlight the singularity character of signal. Then， Holder exponents of the envelope signal were estimated and the curve based on these exponents showed the first arrival time distinctly. Applied the method to AE signals produced by pen lead and metal crack propagation， the first arrival time can be identified correctly. The identified error was less than 2 μs. The research results demonstrated that the proposed method can identified the first arrival time of AE signals precisely.
