中文摘要：

提出一种基于布拉格光纤光栅（fiber Bragg grating，FBG）传感技术测量湿蒸汽湿度的新方法。在理论推导FBG测量湿度模型的研究基础上，利用FBG涂敷湿膨胀材料的技术，把测量湿度的问题转换为FBG测量微应变的技术问题。建立悬臂梁振动频率测量装置，采用FBG精确地测出了前4阶振动频率，与加速度传感器（AD和振动及动态信号采集分析系统（CRAS）等不同方法进行了对比试验，测量结果吻合。对FBG的粘贴位置、激励位置等也进行了试验研究。试验结果证明FBG对悬臂梁微应变（振动）测量有很高的精度和动态特性，且试验的可重复性很好，为下一步测量湿度的试验研究奠定基础。

英文摘要：

This paper presents a method measuring the moisture of wet steam based on the static and dynamic sensing characteristics of fiber Bragg grating （FBG）. And the theoretical model of moisture measurement based on FBG was deduced. Moreover, utilizing the technique of coating the moisture sensitive materials, the moisture of wet steam was measured through measuring the strain response of FBG To strengthen the reliability of measuring the moisture, the experimental devices measuring the frequency of the cantilever was set up. This paper measured the former four modal frequencies accurately based on FBG Comparing with the results based on acceleration transducer and force transducer on the experimental platform using the vibration and dynamic signal acquire analysis system （CRAS）, they are almost the same.Furthermore, the distribution of FBG and the position and magnitude of motivation were investigated in the experiments. The results indicate the excellent dynamic characteristics of FBG and the high precision of measuring the frequency of the cantilever, and demonstrate the good repeatability. Therefore, it lays a firm foundation to research the moisture measurement of wet steam.