摘要
利用杜芬方程Lyapunov指数提出了一种敏感的超声导波识别方法,并通过对钢管中导波信号的检测验证了该方法的有效性。首先,对比了输入Hanning窗调制导波信号与纯噪声信号对系统Lyapunov指数的不同影响,给出了利用Lyapunov指数识别弱超声导波信号的基本原理,并确定了检测系统参数。然后,利用压电传感器在3 m长的钢管中激发和接受超声导波,并将实测导波信号输入杜芬检测系统。研究结果表明,Lyapunov指数可以有效地识别出回波信号中是否存在导波信号,而对于噪声信号Lyapunov指数表现出一定的免疫力,该方法有助于提高管道微缺陷识别的灵敏度。同时,利用输入含噪声的实测导波信号与输入实测纯噪声信号后的两个最大Lyapunov指数之比定义损伤指标,当缺陷在一定范围之内时,该指标具有单调递减性,可用于评估缺陷大小。应用本方法,可有效地提高导波检测的灵敏度。
A sensitive damage detection method was proposed here based on analyzing ultrasonic guided waves signals using Lyapunov exponents of Duffing equation.The feasibility of the method was verified by identifying guided wave signals in a steel pipe.Firstly,a Duffing inspection system and its inspection principle were explained.The determination of system parameters was described in detail.Secondly,the propagation of guided wave in a 3 m-of-length steel pipe was measured experimentally,and the measured signals were analyzed with Duffing inspection system.The test results showed that Lyapunov exponents of Duffing inspection system can be used to effectively identify small defect echos and has a strong immunity to noise simultaneously;in addition,a damage index is defined with the ratio of Lyapunov exponent when inputting measured guided wave signals with noise to that when only inputting measured pure noise signals, it can be used to evaluate the damage level of defects.This method was significant to improve the sensitivity of small defect detection using ultrasonic guided wave.
出处
《振动与冲击》
EI
CSCD
北大核心
2014年第24期82-87,共6页
Journal of Vibration and Shock
基金
国家自然科学基金(11072089
11102125)
山西省自然科学基金(2012021019)
太原科技大学博士启动基金(20102019)
关键词
无损检测
超声导波
LYAPUNOV指数
实验研究
nondestructive examination
ultrasonic guided wave
Lyapunov exponent
experimental study
