Abstract Special equipment is prone to crack damage due to long-term pressure bearing during service. If the cracks in the structure are not detected in time and maintenance work is conducted, severe safety risks will be incurred. To overcome these problems, it is necessary to conduct full-time and full-domain structural on-line monitoring for special equipment to effectively prevent cracking of the special equipment and other safety accidents. Due to the satisfactory detection performance of optical fiber ultrasonic sensor technology, this paper conducted a finite-element simulation calculation and a detection experiment using a cracked plate and a special equipment model. Based on theoretical, simulation and experimental results, a distributed layout scheme of optical fiber ultrasonic sensor units for special equipment was proposed. The crack length, depth and external load conditions were discussed. The influence law of ultrasonic testing signals is employed for the identification and expansion analysis of the internal defects of special equipment with the optical fiber ultrasonic online monitoring technology that is investigated in this paper. A two-dimensional image of the internal defects of the structure is inverted via the time-of-flight method to realize the accurate positioning and quantification of defects, which endows the optical fiber ultrasonic nondestructive testing technology with a visualization functionality.

中文翻译：

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基于光纤超声传感的特种设备健康监测与缺陷成像技术研究

摘要 特种设备在使用过程中，由于长期承压，容易发生裂纹损坏。如果不及时发现结构裂缝并进行维护工作，将会带来严重的安全隐患。为克服这些问题，需要对特种设备进行全时、全域的结构在线监测，有效防止特种设备开裂等安全事故。由于光纤超声波传感器技术的检测性能令人满意，本文利用裂纹板和专用设备模型进行了有限元仿真计算和检测实验。基于理论、仿真和实验结果，提出了一种特种设备光纤超声波传感器单元分布式布置方案。讨论了裂纹长度、深度和外部载荷条件。本文采用光纤超声在线监测技术,利用超声检测信号的影响规律,对特种设备内部缺陷进行识别和扩展分析。通过飞行时间法对结构内部缺陷的二维图像进行反演，实现缺陷的精确定位和量化，赋予光纤超声无损检测技术可视化功能。本文采用光纤超声在线监测技术,利用超声检测信号的影响规律,对特种设备内部缺陷进行识别和扩展分析。通过飞行时间法对结构内部缺陷的二维图像进行反演，实现缺陷的精确定位和量化，赋予光纤超声无损检测技术可视化功能。本文采用光纤超声在线监测技术,利用超声检测信号的影响规律,对特种设备内部缺陷进行识别和扩展分析。通过飞行时间法对结构内部缺陷的二维图像进行反演，实现缺陷的精确定位和量化，赋予光纤超声无损检测技术可视化功能。