Responses of Angle-Beam Ultrasonic Shear Waves to Closed Cracks and Highly Sensitive Quantitative Nondestructive Evaluation of Crack Sizes Together With Closure Stresses

角束超声波剪切波对闭合裂纹的响应以及裂纹尺寸和闭合应力的高灵敏度定量无损评估

• 批准号: 12450041
• 负责人: SAKA Masumi
• 金额: $ 10.11万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450041/
• 关键词: Ultrasonics; Closed Crack; Shear Wave; Ultrasonic Angle-Beam Technique; Inverse Problem; Crack Closing Stress; Crack Depth; Sensitivity; 斜角探傷

1. Clarification of angle-beam shear wave responses to closed cracks and its mechanismSpecimens containing two-dimensional (2D) fatigue cracks with different crack depths and closing stresses were prepared, and the cracks situated vertically on the specimen back-wall were inspected. The beam angle for achieving considerable sensitivity in shear wave response for a wide range of cracks was estimated as 50°.2. Construction of theoretical model of angle-beam shear wave response to closed crackBy taking care of the shape of the response curve that contains the simultaneous information of crack depth and closing stress, the model of angle-beam shear wave response has been proposed.3. Evaluation of crack size and closing stress by inverse analysis(1) Verification for small two-dimensional closed cracksA relation between the amplitude of the crack echo and the crack depth for open cracks was determined. Then, another relation between the reflection coefficient, which is defined by the ratio of echo-height of closed, crack to that of open crack, and crack closure stress was obtained. Finally, by using the model of closed crack response constructed in the previous section 2, which contains these relations, the values of crack closure stress and crack depth of an unknown 2D crack have been determined by solving an inverse problem.(2) Extension to shallow three-dimensional closed cracksThe methodology of evaluating 2D closed crack was extended to shallow 3D closed crack. Since a small segment of length of a 3D shallow crack can be approximated as a segment of 2D crack, the inverse analysis for the response measured at the center of each segment was individually performed.(3) Verification for shallow three-dimensional closed cracksCrack closure stress and the crack tip contour of a 3D closed crack were determined by the technique developed in the above section (2).

1.角梁横波对闭合裂纹响应及其机理的研究制备了含有不同裂纹深度和闭合应力的二维疲劳裂纹的试件，并对试件背面垂直方向的裂纹进行了观察。对于较大范围的裂纹，获得相当敏感的横波响应的梁角估计为50°2。角梁剪切波对闭合裂纹响应理论模型的建立通过考虑同时包含裂纹深度和闭合应力信息的响应曲线的形状，提出了角梁剪切波响应模型。用逆分析计算裂纹尺寸和闭合应力(1)二维闭合小裂纹的验证确定了张开裂纹的裂纹回波幅度与裂纹深度之间的关系。然后，得到了由闭合裂纹与张开裂纹的回波高度之比定义的反射系数与裂纹闭合应力的关系。最后，利用上一节建立的包含这些关系的闭合裂纹响应模型，通过求解一个反问题来确定未知二维裂纹的裂纹闭合应力和裂纹深度。(2)推广到浅三维闭合裂纹将二维闭合裂纹的计算方法推广到浅三维闭合裂纹。由于三维浅裂纹的一小段长度可以近似为一段二维裂纹，因此对每一段中心测得的响应分别进行了反分析。(3)浅三维闭合裂纹的验证利用上一节(2)中发展的技术确定了三维闭合裂纹的裂纹闭合应力和裂纹尖端轮廓。

项目成果

M.A.Salam Akanda (M.Saka): "Influence of Crack Length on the Ultrasonic Evaluation of Depth of Small Surface Cracks"Proc.Asian Pacific Conf.on Fracture and Strength '01 and Int.Conf.Advanced Technology in Experimental Mechanics '01. 1. 253-257 (2001)

M.A.Salam Akanda (M.Saka)：“裂纹长度对小表面裂纹深度超声评估的影响”Proc.Asian Pacific Conf.on Fracture and Strength 01 和 Int.Conf.Advanced Technology in Experimental Mechanics 01。

M. A. Salam Akanda ( M. Saka ): "Toward a Sensitive Detection and Sizing of Small Closed Cracks by Ultrasonic Shear Waves"Proc. Asian Pacific Conf. on Fracture and Strength '01 and Int. Conf. Advanced Technology in Experimental Mechanics '01. 258-263 (200

M. A. Salam Akanda (M. Saka)：“通过超声波剪切波实现小型闭合裂纹的灵敏检测和尺寸测量”Proc。

坂 真澄: "閉じたき裂の非破壊評価"日本機械学会関西支部第77期定時総会講演会 講演論文集. (印刷中). (2002)

Masumi Saka：“闭合裂纹的无损评估”日本机械工程师学会关西分会第 77 届年会论文集（2002 年）。

M.A.Salam Akanda (M.Saka): "Ultrasonic Shear Wave Technique for Sensitive Detection and Sizing of Small Closed Cracks"JSME International Journal. (印刷中). (2002)

M.A.Salam Akanda (M.Saka)：“用于小型闭合裂纹的灵敏检测和尺寸测量的超声波剪切波技术”JSME 国际期刊（2002 年）。

S. R. Ahmed (M. Saka): "Effect of Plate Thickness on the Ultrasonic NDE of Small Closed Surface Cracks"Proc. Int. Workshop on Sensing and Evaluation of Materials System. 48-55 (2000)

S. R. Ahmed (M. Saka)：“板厚度对小闭合表面裂纹超声无损检测的影响”Proc。