毕业论文（设计）脉冲涡流检测的频域分析研究.doc

脉冲涡流检测的频域分析研究

摘要:脉冲涡流检测采用脉冲激励,能够检测到不同深度的缺陷,获取更为丰富的缺陷信息,对保证飞机安全也有着非凡的意义,因此引起了众多研究人员的兴趣。
脉冲涡流含有非常丰富的频率谱信息,因此脉冲涡流检测频域分析的研究具有重大的意义。
本论文首先设计、制作了脉冲涡流检测频域分析所需要的圆形探头,在被检缺陷试块上采集脉冲涡流检测信号。
论文对采集的信号通过FIR滤波、IIR滤波以及小波进行降噪方面的研究,比较了三种去噪方法,最后选取了去噪效果更好的小波去噪方法对检测信号进行去噪。
论文接着对时域的缺陷信号进行差分处理,然后再对差分处理过的时域信号利用MATLAB编写分析算法进行傅里叶变换,进行频谱分析方面的研究。分析了不同频率对腐蚀缺陷信号的影响。通过分析发现低频分量有利于检测深层缺陷,高频分量有利于检测浅层缺陷。
关键字:脉冲涡流检测腐蚀缺陷频域分析
指导老师签字:
Frequency domain analysis of pulsed eddy current testing
Student name:Ding Beibei class: 110813
Supervisor:Fu Yuewen
Aastract: Pulsed eddy current testing using pulsed excitation, able to detect defects at different depths, get richer defect information, to ensure the safety of the aircraft also has a special significance, and therefore aroused the interest of many researchers.
Pulsed eddy current frequency spectrum is very rich in information, so research pulsed eddy current testing frequency domain analysis is of great significance.
In this thesis, the design, production of the circular probe pulsed eddy current testing frequency domain analysis required to collect pulsed eddy current testing signal defect in the subject test block.
Thesis for signal acquisition through FIR filtering, IIR filtering, and wavelet research noise reduction, comparing the three de-noising method, and finally selected denoising method the detection signal de-noising.
Then the paper defect differential time domain signal processing, and then treated the difference time-domain signal analysis algorithms using MATLAB prepared Fourier transform, spectral analysis of the study. The effects of different frequencies of corrosion defect signal. The analysis revealed that low-ponent is conducive to deep defect detection, detection of high ponents in favor of shallow defects.
Keywords: Pulsed eddy current testing Corrosion defects
Frequency domain analysis

Signature of supervisor:
目录
1 引言
选题的依据和意义 1
国内外研究概况及发展趋势(含文献综述) 2
国外研究现状 2
国内研究现状 3