镁合金超声检测的相关增强小波去噪技术  

Ultrasonic Testing of Casting Magnesium Alloy Based on Wavelet De-noising Methods of Correlation Enhancement

作　　者：陈振华[1] 赵二虎[1] 胡怀辉[1] 

机构地区：[1]无损检测技术教育部重点实验室(南昌航空大学),南昌330063

出　　处：《失效分析与预防》2012年第2期69-71,90,共4页Failure Analysis and Prevention

基　　金：国家自然科学基金(11104129);无损检测技术教育部重点实验室开放基金(ZD201029001)

摘　　要：提出了一种基于相关增强与小波阈值相结合的超声信号去噪方法,将该方法用于AZ91镁合金的超声检测能够有效地去除噪声,提高检测精度。由于同类缺陷信号之间相关性较大,因此对同类缺陷的超声信号进行相关处理能够增强缺陷信号;结合小波分析的多分辨分析特点,从频率和时域对增强后的信号进行阈值处理,最终获得了良好的去噪效果。实验结果表明:该方法能够有效去除由粗晶散射引起的结构噪声,对微弱缺陷信号的检测是很有效的,且灵活便捷。A signal processing method based on the combination of cross-correlation strengthening algorithm and wavelet threshold value was put forward. This method was used during ultrasonic testing of magnesium alloy AZ91 to remove the noise signal and improve the testing accuracy. The signals from the same kind of defects has much correlation, so the defect signals can be strengthened by cross-correlation algorithm. Besides, the threshold method of wavelet analysis is adopted to strengthen signal after using cross-correlation algorithm and good de-noising results are obtained. The results indicate that the noise caused by coarse grain scattering can be eliminated by using this method and this method can effectively detect tiny defects.

关 键 词：镁合金 超声检测 小波分析 相关性 

分 类 号：TG115.28[金属学及工艺—物理冶金]