中文摘要：

利用光纤Bragg光栅（FBG）来测量汽轮机叶片的模态频率．在无约束条件下，FBG测得叶片4阶模态频率分别为1005．00、2048．00、2297．25和2786．00Hz．当叶片受约束时，FBG测得叶片3阶模态频率分别为921．50、1482．00和2454．75Hz．为分析FBG测量结果的可靠性，采用加速度传感器（AT）进行对比测量，在无约束条件下其结果分别为1005．00、2048．00、2297．00和2786．00Hz；在有约束条件下，其结果分别为917．00、1480．75和2454．25Hz．结果表明，FBG和AT对叶片模态频率的测量结果十分吻合．通过研究FBG的解调和波分复用方式，实现两个FBG对叶片进行同时测量．因此FBG可组成传感网络，进行多点测量，用于汽轮机叶栅频率的测量．通过实现进入FBG和出射的光路非接触耦合方式，FBG可用于旋转部件的测量和叶片的动频测量．

英文摘要：

Modal frequencies of turbine blade were measured based on fiber Bragg grating （FBG）. Four stagesof modal frequencies were obtained without constraint condition by the FBG, i. e. , 1 005.00,2 048.00, 2 297.25 and 2 786.00 Hz. Three stages of modal frequencies were also obtained with constraint condition, i. e. , 921.50,1 482.00 and 2 454.75 Hz. An acceleration transducer （AT） was utilized to testify the reliability of FBG measuring method. The results without constraint condition were 1 005.00,2 048. 00, 2 297.00 and 2 786.00 Hz, and the modal frequencies with constraint condition were 917.00,1 480.75 and 2 454.25 Hz. Experimental results demonstrated the modal frequencies based on FBG agreed with those by using the AT. The modal frequencies of blade were simultaneously measured by two FBGs by investigating the interr.ogator and wave division multiplexing method of FBG. So FBG can be constructed into sensing network and measure the frequencies of blade cascade. FBG can measure the frequencies of rotating parts and the dynamic frequencies of turbine blade by using non-contact coupled mode.