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Development of Ultrasonic Angle Beam Technique of Quantitative Nondestructive Evaluation of Small Closed Cracks

微小闭合裂纹定量无损评价超声角束技术的发展

基本信息

批准号：
10450042
负责人：
SAKA Masumi
金额：
$ 4.8万
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：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450042/
关键词：
Nondestructive Testing Ultrasonics Crack Crack Closure Ultrasonic Angle Beam Technique Small Angle of Incidence Inverse Problem Theoretical Model 超音波斜角探傷

项目摘要

The main results obtained are as follows :1. Clarification of mechanism to enhance the sensitivity of ultrasonic inspection of closed cracks using the ultrasonic angle beam techniqueA new evaluation approach, namely the optimum incidence method, has been developed, which provides the way to deal with sensitivity to the smaller cracks, specially the closely ones. It has been verified experimentally by using both fully open and tightly closed 2-D cracks that the evaluation sensitivity can be enhanced significantly when the beam is directed with a small angle of incidence, θィイD2iィエD2 【similar or equal】 2 deg., the response of which is characterized by the nearly antisymmetric variation in amplitude of the back-wall echo signal around the position of the crack.2. Establishment of theoretical modeling of ultrasonic angle beam response for the evaluation of small closed cracksFor 2-D fatigue cracks having depth of 0.5〜5.0 mm, we have developed method for sizing their depths together with the information of crack closure, by solving an inverse problem on a personal computer. The evaluation method has been extended for plates having different thickness and also for different materials, where it has been found that the evaluation sensitivity is enhanced significantly for the case of thinner plates.3. Extension of the evaluation method to small 3-D closed cracksThe evaluation method developed above has well been extended to small 3-D closed cracks.4. Verification of the method by using small closed 3-D surface cracksWe have verified that the method can be successfully applied for the evaluation of depths of small 3-D closed cracks together with the information of their crack closure.

取得的主要结果如下： 1．澄清利用超声波角束技术增强闭合裂纹超声波检测灵敏度的机制开发了一种新的评估方法，即最佳入射法，它提供了处理较小裂纹（特别是紧密裂纹）灵敏度的方法。通过使用全开和紧闭二维裂纹进行实验验证，当波束以小入射角θィイD2iィエD2【相似或等于】2°定向时，可以显着提高评估灵敏度，其响应表现为裂纹位置周围后壁回波信号幅度的近反对称变化。 2．建立用于评估小型闭合裂纹的超声波角束响应理论模型对于深度为 0.5〜5.0 mm 的二维疲劳裂纹，我们开发了通过在个人计算机上求解逆问题来确定其深度以及裂纹闭合信息的方法。该评价方法已扩展到不同厚度和不同材料的板材，发现对于较薄的板材，评价灵敏度显着提高。 3．将评估方法扩展到小的3-D 闭合裂纹上面开发的评估方法已经很好地扩展到小的3-D 闭合裂纹。4．使用小型闭合 3-D 表面裂纹验证该方法我们已经验证，该方法可以成功应用于评估小型 3-D 闭合裂纹的深度及其裂纹闭合信息。