基于相切关系的圆柱体构件内部缺陷重构算法研究

发布时间：2018-05-13 22:10

本文选题：超声检测 + 缺陷重构　；参考：《中北大学》2017年硕士论文

【摘要】：以管材、棒材及轴类为典型代表的圆柱体构件广泛应用于多个领域,对其进行缺陷检测是确保生产和使用安全的重要环节。本文针对圆柱体构件,以超声技术为检测方法,研究了其内部缺陷重构算法。本文针对圆柱体构件及其内部缺陷类型,介绍了超声检测方法、原理及超声传播特性,并采用PZFlex软件仿真的声压图分析了超声波在界面和缺陷处的传播情况;通过实例分析了传统渡越时间重构方法的不足及其产生的原因,结合超声波的传播特性,提出了基于相切关系的缺陷边界重构方法;根据圆、椭圆、矩形与圆的几何关系,研究了圆孔、椭圆孔、裂纹缺陷边界重构方法及其实现算法,并针对椭圆与圆相切不易求解闭合解得问题,提出了局部区域采用圆逼近的方法实现了椭圆孔缺陷与波前圆弧相切的求解问题。然后通过实际人工缺陷的采集数据和PZFlex仿真缺陷回波信号对上述的重构实现算法进行了验证和精度考核,结果表明重构结果的平均相对误差都不超过5%,重构结果良好;为了准确提取用于缺陷重构的缺陷回波时间特征量,将缺陷回波通过反卷积计算,准确地提取了时间延时信息。
[Abstract]:Cylindrical components, which are typically represented by pipes, bars and shafts, are widely used in many fields. Defect detection is an important step to ensure the safety of production and use. In this paper, the internal defect reconstruction algorithm is studied based on ultrasonic technique for cylindrical components. In this paper, the ultrasonic testing method, principle and ultrasonic propagation characteristics are introduced for cylindrical components and their internal defect types. The ultrasonic propagation at the interface and defects is analyzed by using the sound pressure diagram simulated by PZFlex software. This paper analyzes the shortcomings of the traditional transit time reconstruction method and its causes through an example, and proposes a defect boundary reconstruction method based on tangent relation, which is based on the geometrical relations of circle, ellipse, rectangle and circle, combined with the propagation characteristics of ultrasonic wave. In this paper, the boundary reconstruction method of circular hole, elliptical hole and crack defect and its realization algorithm are studied. The closed solution is not easy to be solved by ellipse and circle tangent. A circular approximation method is proposed to solve the problem of elliptical hole defect and wave front arc tangent. Then the reconstruction algorithm is verified and the accuracy is checked by the actual data collected by artificial defects and the PZFlex simulation defect echo signal. The results show that the average relative error of the reconstruction results is not more than 5 parts, and the reconstruction results are good. In order to accurately extract the time characteristic of defect echo for defect reconstruction, the time delay information is accurately extracted by deconvolution calculation.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB559

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