A study on improvement of ultrasonic inspection.

为了提高超声检测的质量，本研究从多个方面进行了研究，取得了许多重要成果。本文首先对超声波检测在土木工程领域应用的重要课题进行了研究。阐明了提高超声波探伤质量必须解决的问题。第二部分通过有限元分析，确定了超声波的传播路径和探头的最佳位置。第三部分研究了超声波检测数据的分析方法。为了提高超声检测的时间分辨率，研究了数值反卷积分析、最大熵方法。该方法能有效地抑制噪声的影响，具有较高的时间分辨率。此外，还研究了孔径综合系统，利用该系统获得了高的时间分辨率。此外，为了表征钢构件的缺陷，研究了超声层析成像方法的应用。第四部分，作为超声检测在实际问题中的应用实例，研究了界面裂缝的应用。最后，对超声波检测在实际钢桥中的应用，特别是自动化超声波检测中存在的问题进行了评述。

In order to improve ultrasonic inspection, in this study many aspects of this field were studied and many important results were obtained. Firstly, the important topics of application of ultra sonic inspection for civil engineering field were researche. Some problems, which must be solved to improve the ultrasonic inspection, were clarified. In second section, FEM analysis were carried out to know the moving path of ultrasonic wave and the best location of probe. In third section, the way to analyze the data of ultrasoic inspection were studied. To improve the time-resolution of ultrasonic inspection, numerical deconvolution analysis, maximum entropy method were studied. This methods could prevent noise effect and have high time-resolution. In addition, aperture synthesis system were studied and by using this system high time-resolution were obtained. Furthermore, to characterize the flaws of steel members, the application of the imaging method of ultrasonic tomography was studied.In fourth section, as a example of application of ultrasonic inspection for actual problems, the application for interface cracks was studied. Finally, in last section, problems in the application of ultrasonic inspection for actual steel bridges, especially automatic ultrasonic inspection, were reviewed.