【摘要】：利用杜芬方程Lyapunov指數(shù)提出了一種敏感的超聲導(dǎo)波識(shí)別方法,并通過對(duì)鋼管中導(dǎo)波信號(hào)的檢測(cè)驗(yàn)證了該方法的有效性。首先,對(duì)比了輸入Hanning窗調(diào)制導(dǎo)波信號(hào)與純?cè)肼曅盘?hào)對(duì)系統(tǒng)Lyapunov指數(shù)的不同影響,給出了利用Lyapunov指數(shù)識(shí)別弱超聲導(dǎo)波信號(hào)的基本原理,并確定了檢測(cè)系統(tǒng)參數(shù)。然后,利用壓電傳感器在3 m長(zhǎng)的鋼管中激發(fā)和接受超聲導(dǎo)波,并將實(shí)測(cè)導(dǎo)波信號(hào)輸入杜芬檢測(cè)系統(tǒng)。研究結(jié)果表明,Lyapunov指數(shù)可以有效地識(shí)別出回波信號(hào)中是否存在導(dǎo)波信號(hào),而對(duì)于噪聲信號(hào)Lyapunov指數(shù)表現(xiàn)出一定的免疫力,該方法有助于提高管道微缺陷識(shí)別的靈敏度。同時(shí),利用輸入含噪聲的實(shí)測(cè)導(dǎo)波信號(hào)與輸入實(shí)測(cè)純?cè)肼曅盘?hào)后的兩個(gè)最大Lyapunov指數(shù)之比定義損傷指標(biāo),當(dāng)缺陷在一定范圍之內(nèi)時(shí),該指標(biāo)具有單調(diào)遞減性,可用于評(píng)估缺陷大小。應(yīng)用本方法,可有效地提高導(dǎo)波檢測(cè)的靈敏度。
[Abstract]:A sensitive ultrasonic guided wave identification method is proposed by using Lyapunov exponent of Duffin equation. The validity of this method is verified by detecting the guided wave signal in steel tube. Firstly, the different effects of the input Hanning window modulated guided wave signal and pure noise signal on the Lyapunov exponent of the system are compared, and the basic principle of using Lyapunov exponent to identify the weak ultrasonic guided wave signal is given, and the parameters of the detection system are determined. Then, the ultrasonic guided wave is excited and received by piezoelectric sensor in a steel tube 3 m long, and the measured guided wave signal is input into Duffin detection system. The results show that the Lyapunov exponent can effectively identify whether there is a guided wave signal in the echo signal, and the Lyapunov exponent of the noise signal shows a certain immunity. This method is helpful to improve the sensitivity of the pipeline micro-defect identification. At the same time, the damage index is defined by using the ratio of the two largest Lyapunov exponents after the input noise signal and the input pure noise signal. When the defect is within a certain range, the index is monotone decreasing. Can be used to evaluate defect size. By using this method, the sensitivity of guided wave detection can be improved effectively.
【作者單位】： 太原科技大學(xué)力學(xué)系;暨南大學(xué)理工學(xué)院;
【基金】：國(guó)家自然科學(xué)基金(11072089,11102125) 山西省自然科學(xué)基金(2012021019) 太原科技大學(xué)博士啟動(dòng)基金(20102019)
【分類號(hào)】：TN911.7

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