基于BOTDA的温度和应变测试探讨

Temperature and Strain Test Based on BOTDA

基于布里渊散射的分布式光纤传感系统同时具有远距离测量和高精度测量的特点,因此在土木工程监测领域中的运用越来越广泛。根据光纤布里渊频移与光纤应变、温度之间的关系,可以确定光纤各小区间上能量转移达到最大时的频率差,从而得到温度和应变信息,实现分布式测量。基于BOTDA的分布式光纤测量系统可以同时测量温度和应变,大大提高了光纤测量的效率。研究发现,在温度测试中光纤的保护层厚度制约了光纤测温的精度,对光纤保护层改进可以提高测温的准确性。在应变测试中,基于BOTDA的分布式光纤测量系统对应变测试可以很简便地进行温度补偿,简化了传统应变片测量中的温度补偿,提高了应变测量的准确性,具有很高的性价比。

Distributed optical fiber sensing system based on Brillouin scattering is capable of remote and highly accurate measurement.Accordingly,it has been used widely in the monitoring field of civil engineering.According to the relationship between Brillouin frequency shift and the optical fiber strain,and between Brillouin frequency shift and temperature,the frequency difference among various areas when the optical energy transfer reaches the maximum can be determined,thus the authors can get the temperature and strain information to achieve distributed measurement.As the distributed optical fiber measurement system based on BOTDA can simultaneously measure temperature and strain,it has greatly improved the efficiency of optical measurements.Temperature test shows that the accuracy of temperature measurement is restricted by the protective layer thickness of optical fiber.Therefore,it can be increased by improving the protective layer.As for the strain test,distributed optical fiber measurement system based on BOTDA proves to have excellent performance-price ratio as it makes the temperature compensation easy,and consequently simplifies the temperature compensation in the traditional strain gauge measuring method,and improves the accuracy of strain measurement.