铝蒙皮蜂窝板粘接质量的超声导波检测技术基础研究

发布时间：2018-05-30 08:27

本文选题：超声检测 + 导波　；参考：《北京航空航天大学》2016年博士论文

【摘要】：为了实现铝蒙皮蜂窝板粘接质量的快速无损检测,研究了铝蒙皮蜂窝板粘接质量超声导波检测的相关理论和方法,设计了一套铝蒙皮蜂窝板粘接质量超声导波检测系统。首先研究了单层板和双层板中导波的相关理论。建立了薄铝板和双层板中导波的数学模型,编程计算了导波的频散曲线,分析了导波的波结构,采用有限元法分别对薄铝板和双层板中的导波做了数值仿真。针对胶接结构中一般比较薄的胶层,研究了胶层对铝蒙皮蜂窝板中导波产生的影响。接着设计了铝蒙皮蜂窝板的超声导波检测系统。确定了探头频率,选择了导波检测模式,设计了超声导波的激励和接收方式,编写了超声导波检测系统的控制软件,在此期间,提取了检测脱粘缺陷的第一个特征值:信号电压幅值。然后针对导波信号的非平稳特性和频散现象,研究了超声导波信号的处理方法。采用均值平滑滤波法和小波降噪法对信号进行了降噪处理,消除了信号中的大部分随机噪声;分别用短时傅立叶变换和小波变换两种时频分析方法对导波信号进行了时频分析,得到了导波传播过程中模式发生变换的相关情况;采用Mallat算法对导波信号进行了多分辨率分析,提取了脱粘缺陷判别的第二个特征值:d3小波细节信号。最后分别采用S0和A0模式分别对不同的脱粘缺陷和对铝蒙皮蜂窝板试样的脱粘缺陷进行了检测试验,针对一发一收检测方式不能对缺陷进行定位和大小判断的不足,提出了X-Y二维线扫描叉乘叠加法对一发一收检测方式下的导波线扫描成像方法。试验结果表明:采用频厚积为1.5MHz-mm的A0模式对铝蒙皮蜂窝板脱粘缺陷的检测效果较好,利用X-Y二维线扫描叉乘叠加法可有效实现一发一收检测方式下导波信号成像。与传统超声波穿透法相比,采用导波法检测蜂窝板试样,其检测效率可提高27.5倍。
[Abstract]:In order to realize the fast nondestructive testing of the bonding quality of aluminum coated honeycomb plate, the theory and method of ultrasonic guided wave testing for bonding quality of aluminum coated honeycomb plate were studied, and a set of ultrasonic guided wave testing system for bonding quality of aluminum coated honeycomb plate was designed. Firstly, the theory of guided wave in single layer plate and double layer plate is studied. The mathematical model of guided wave in thin aluminum plate and bilayer plate is established, the dispersion curve of guided wave is calculated by programming, the wave structure of guided wave is analyzed, and the numerical simulation of guided wave in thin aluminum plate and bilayer plate is done by using finite element method. In this paper, the influence of adhesive layer on the guided wave in aluminum honeycomb plate is studied. Then the ultrasonic guided wave detection system of aluminum honeycomb plate is designed. The probe frequency is determined, the guided wave detection mode is selected, the excitation and receiving mode of ultrasonic guided wave is designed, and the control software of ultrasonic guided wave detection system is compiled. The first characteristic value for detecting debonding defect is extracted: the amplitude of signal voltage. Then, the processing method of ultrasonic guided wave signal is studied according to the nonstationary characteristic and dispersion phenomenon of guided wave signal. The mean smoothing filtering method and wavelet denoising method are used to reduce the noise of the signal to eliminate most of the random noise in the signal, and two time-frequency analysis methods, the short-time Fourier transform and the wavelet transform, are used to analyze the pilot wave signal. The correlation of mode transformation in the process of guided wave propagation is obtained, and the Mallat algorithm is used to analyze the guided wave signal with multi-resolution, and the second eigenvalue: D3 wavelet detail signal is extracted for the discrimination of debonding defects. Finally, the S0 and A0 modes were used to detect the different debonding defects and the debonding defects of aluminum honeycomb plates, respectively. In this paper, the X Y two dimensional scanning cross multiplication superposition method is proposed for the guided line scanning imaging under one source and one receiving detection mode. The experimental results show that the A0 mode with frequency thickness product (1.5MHz-mm) is effective in detecting the debonding defects of aluminum honeycomb plates. The X-Y two-dimensional scanning cross multiplication superposition method can effectively realize the guided wave signal imaging under the mode of "one send and one receive" detection. Compared with the traditional ultrasonic penetration method, the efficiency of detecting honeycomb plate by guided wave method can be increased by 27.5 times.
【学位授予单位】：北京航空航天大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG115.285

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