厚度无损检测仪器的精度长期稳定性研究

无损检测和结构健康监测是保障工业生产安全、降低维护成本的重要技术。在结构健康监测领域，原位测量仪器的长期稳定性尤为重要。首先介绍电磁、超声无损检测在厚度检测的应用现状，针对随后讨论厚度无损检测检测仪器精度长期稳定性问题。对厚度无损检测仪器现在长期使用过程中的精度变化规律进行研究，探讨三种测厚仪器的工作原理、精密度和准确度与仪器的稳定性的关系。采用三种厚度测量仪器（超声测厚仪、涂覆层测厚仪与楼板测厚仪）测量预标定样本的仪器试验测量方法，得到五年测量数据。再通过分析数据的年平均误差、相对误差和变化速率来讨论电涡流测厚仪、超声测厚仪的长期稳定性，并进行三类仪器间的比较，分析各类型仪器的特点。结果显示电涡流厚度测量仪器具有相对较好的长期稳定性；超声测厚仪和楼板测厚仪精密度维持能力受时间影响，仪器精密度逐年下降，准确度也趋于不稳定。为电磁无损检测技术应用到结构健康监测领域，自校准和补偿奠定了基础。

Investigating Long Term Stability of Nondestructive Testing Equipment in Thickness Measuring

Non-destructive Testing (NDT) and Structural Health Monitoring (SHM) are important technologies well used in industrial production for ensuring safety and reducing cost. In the field of SHM, the long-term stability of in situ measuring instrument is particularly important. The application of thickness measurement using electromagnetic and ultrasonic non-destructive testing respectively is introduced, then the challenges existing in maintaining the long term stability of thickness non-destructive testing is analysed. In order to explore the accuracy variation of the instruments in the process of long-term use measurement, data are obtained by using three thickness measuring instruments to detect pre-calibrated samples for a five-year term. The long-term stability of eddy current and ultrasonic thickness gauge is discussed by analysing the annual mean error, relative error and change rate of them. It shows that the electromagnetic thickness measuring instrument has a better long-term stability, the accuracy of ultrasonic thickness measuring instrument changed over time, and the accuracy of floor thickness measuring instrument tends to be unstable, which lays a foundation for the application of electromagnetic non-destructive testing technology in SHM for self-calibration and compensation.