基于磁致伸缩导波的拱桥吊杆无损检测实验研究
发布时间：2019-03-22 13:24
【摘要】：拱桥吊杆是现代中下承式拱桥重要的传力构件,其结构健康状况关系着桥梁的安全使用。本文结合国家自然科学基金项目"基于磁致伸缩导波动态聚焦原理的拱桥吊杆腐蚀断丝在线检测方法"(NO.61271084),开展了拱桥吊杆导波无损检测实验研究。本文针对传统导波检测方向识别方法中存在的不足,提出了基于时延估计的导波检测信号方向识别方法。通过将基本互相关时延估计方法和LMS自适应滤波时延估计方法引入到传统导波检测方向识别方法中,克服了传统方法中方向识别能力受实际波速影响和检测频率受换能器限制的问题。最后通过实验对本文提出的方法和传统方法进行了对比研究,证明本文提出的方法在换能器和检测频率匹配时比传统方法的方向识别能力略强,在换能器和检测频率失配时方向识别效果远远好于传统方法。针对吊杆中导波信号严重频散引起的检测分辨力下降和信号衰减问题,开展了时间反转聚焦技术的基本理论研究及其在拱桥吊杆的导波检测信号频散补偿中的应用研究。通过Abaqus软件对拱桥吊杆进行建模和仿真研究,验证了时间反转聚焦方法能够在特定位置使得拱桥吊杆中导波信号形成聚焦,从而实现对导波检测信号的频散补偿。
[Abstract]:Arch bridge hanger is an important force transfer component of modern middle-bottom arch bridge, and its structural health is related to the safe use of the bridge. In this paper, combined with the project of National Natural Science Foundation of China, "on-line testing method of corrosion broken wire of arch bridge hanger based on magnetostrictive guided wave dynamic focusing principle" (NO.61271084), experimental research on non-destructive testing of arch bridge hanger by guided wave is carried out. In this paper, a new direction recognition method for guided wave detection based on time delay estimation is proposed, aiming at the shortcomings of the traditional direction recognition method for guided wave detection. The basic cross-correlation time delay estimation method and the LMS adaptive filtering delay estimation method are introduced into the traditional direction identification method of guided wave detection. It overcomes the problem that the traditional method is influenced by the actual wave velocity and the detection frequency is limited by the transducer. Finally, a comparative study of the proposed method and the traditional method is carried out through experiments. It is proved that the proposed method is a little stronger than the traditional method in direction recognition when the transducer and the detection frequency are matched. When the transducer and the detection frequency are mismatched, the direction recognition effect is much better than the traditional method. In order to solve the problem of decreasing detection resolution and signal attenuation caused by severe dispersion of guided wave signal in hanger, the basic theoretical research of time reversal focusing technique and its application in dispersion compensation of guided wave detection signal of arch bridge hanger are carried out. The modeling and simulation of arch bridge hanger is carried out by Abaqus software. It is verified that the time reversal focusing method can focus the guided wave signal in the arch bridge hanger at a specific position, thus realizing the dispersion compensation of the guided wave detection signal.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U446
[Abstract]:Arch bridge hanger is an important force transfer component of modern middle-bottom arch bridge, and its structural health is related to the safe use of the bridge. In this paper, combined with the project of National Natural Science Foundation of China, "on-line testing method of corrosion broken wire of arch bridge hanger based on magnetostrictive guided wave dynamic focusing principle" (NO.61271084), experimental research on non-destructive testing of arch bridge hanger by guided wave is carried out. In this paper, a new direction recognition method for guided wave detection based on time delay estimation is proposed, aiming at the shortcomings of the traditional direction recognition method for guided wave detection. The basic cross-correlation time delay estimation method and the LMS adaptive filtering delay estimation method are introduced into the traditional direction identification method of guided wave detection. It overcomes the problem that the traditional method is influenced by the actual wave velocity and the detection frequency is limited by the transducer. Finally, a comparative study of the proposed method and the traditional method is carried out through experiments. It is proved that the proposed method is a little stronger than the traditional method in direction recognition when the transducer and the detection frequency are matched. When the transducer and the detection frequency are mismatched, the direction recognition effect is much better than the traditional method. In order to solve the problem of decreasing detection resolution and signal attenuation caused by severe dispersion of guided wave signal in hanger, the basic theoretical research of time reversal focusing technique and its application in dispersion compensation of guided wave detection signal of arch bridge hanger are carried out. The modeling and simulation of arch bridge hanger is carried out by Abaqus software. It is verified that the time reversal focusing method can focus the guided wave signal in the arch bridge hanger at a specific position, thus realizing the dispersion compensation of the guided wave detection signal.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U446
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