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Development of Ultrascnic Flaw Detection System for Quantitative Evaluation of Fatigue Damage of Existing Steel Structures

现有钢结构疲劳损伤定量评价超声波探伤系统的研制

基本信息

批准号：
15206055
负责人：
MIKI Chitoshi
金额：
$ 28.79万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

This study considered following items and show the possibility of developing UT system for quantitative evaluation.1. Development of a database for the fatigue crack detection in existing steel structures and consultation system based on the database :The database of the location, cause, and retrofit work of the fatigue damage was developed and it was showed that the importance of the detection of cracks from defect for the maintenance.2. Numerical simulation about characteristic of ultrasonic echo :In order to develop linear array flaw detection system, wave propagation simulation was carried out to optimize the arrangement of piezoelectoric device in proves. Then effective arrangement for 2 MHz and 5 MHz were proposed.3. Verification of the characteristics of ultrasonic echo from fatigue crack :It was showed that crack tip opening and closing behavior could be detected as the change of ultrasonic echo intensity non-destructively, and that possibility of fatigue crack identification by visualization using SAFT technique.4. Development of array ultrasonic flaw detection system :Three dimensional flaw detection systems in steel using tandem or two dimensional array probes were developed.5. Improvement of the accuracy of ultrasonic flaw detection systems by signal processing :Three dimensional visualization techniques with high objectivity and accuracy was developed. Accuracy of visualization to detect the location of crack tip by SAFT technique etc was evaluated.6. Verification by experiment using steel structural models :Ability of the weld defects detection was verified by using the model of steel bridge frame piers, which is fatigue problem was found recently, then it was checked that internal weld defects can be detected accurately even if the defect had three dimensional shapes.From the these results, it can be established that ultrasonic flaw detection system to evaluate fatigue damage objectively.

本研究考虑了以下几点并展示了开发UT系统进行定量评估的可能性： 1．现有钢结构疲劳裂纹检测数据库及基于该数据库的咨询系统的开发：开发了疲劳损伤的位置、原因和改造工作数据库，表明了缺陷裂纹检测对于维修的重要性。 2．超声回波特性数值模拟：为了研制线阵探伤系统，进行了波传播模拟，优化了压电器件的布置。然后提出了2 MHz和5 MHz的有效安排。 3．疲劳裂纹超声回波特征验证：表明可以通过超声回波强度的变化无损地检测出裂纹尖端的张开和闭合行为，并通过SAFT技术可视化识别疲劳裂纹的可能性。 4．阵列超声探伤系统研制：开发了采用串联或二维阵列探头的钢材三维探伤系统。 5．通过信号处理提高超声波探伤系统的精度：开发了具有高客观性和准确性的三维可视化技术。对SAFT技术等可视化检测裂纹尖端位置的准确性进行了评价。 6．钢结构模型实验验证：利用最近发现的疲劳问题的钢桥框架桥墩模型验证了焊缝缺陷检测的能力，验证了即使缺陷具有三维形状，也能准确检测出内部焊缝缺陷。由此可以建立客观评价疲劳损伤的超声波探伤系统。