基于包络H觟lder指数的AE信号初至时刻精确拾取.PDF

第39卷第4期 中国测试 Vol.39 No.4 2013年7月 CHINA MEASUREMENT TEST July，2013 基于包络H觟lder指数的AE信号初至时刻精确拾取 李 力袁 李 骥 （三峡大学）， （水电机械设备设计与维护湖北省重点实验室 湖北 宜昌 443002） 摘 要院声发射（AE）信号初至时刻精确拾取是声发射源定位中的关键问题，该文探讨基于连续小波变换的H觟lder指 数方法拾取AE信号初至时刻，为突出信号初至时刻的奇异性特征，提出对信号包络估计的包络H觟lder指数方法。通 过对模拟AE信号和金属裂纹AE信号应用结果表明：包络H觟lder指数可以精确提取AE信号的初至时刻，误差小于 2滋s，能为AE源定位提供一种有效手段。 （ ；包络 ；奇异性 关键词院声发射 AE）；初至时刻 H觟lder指数 中图分类号院TB553曰TB95曰O429曰TM930.12 文献标志码院A 文章编号院1674-5124渊2013冤04-0001-04 Precise identification of first arrival time for acoustic emission signal based on envelope H觟lder exponent LI Li，LI Ji （Hubei Key Laboratory of Hydroelectric Machinery Design Maintenance, China Three Gorges University， Yichang 443002，China） Abstract: 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 H觟lder 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，H觟lder 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滋s. The research results demonstrated that the proposed method can identified the first arrival time of AE signals precisely. Key words: acoustic emission（AE）；first arrival time；envelope H觟lder expo