温度自补偿光纤光栅应变传感器研制及其在索力测量中的应用

光纤光栅应变传感器在测量过程中存在温度和应变交叉影响的问题,且温度对应力测量结果影响较大。为获得精确的应力测量结果,必须大幅度减少或消除温度的影响。目前参考光栅法或温度测量系数修正法,难获得理想的结果。文中提出以截面对称的悬臂梁结构作为敏感元件,利用其上下表面拉压异号等应变和温度变化同应变的原理,通过在悬臂梁上下表面对称粘贴两根光纤光栅,利用结果差来消除温度影响,并提高测量灵敏度。文中对此种温度自补偿新型光纤光栅应变传感器的传感性能进行了研究,并将此类传感器安装在拉索的锚具上进行索力测量。研究结果表明:研制的光纤光栅应变传感器,能大幅度降低温度的影响,达到温度自补偿的目的;将此类传感器用于索力测量,具有较高的精度及灵敏度,能满足工程应用的实际需要。

Development of temperature self-compensated fiber Bragg grating strain sensor and its application in cable force measurement

Fiber Bragg grating strain sensors have the problem of cross-influence between temperature and strain during measurement, and temperature has a significant impact on stress measurement results. To obtain accurate stress measurement results, it is necessary to significantly reduce or eliminate the impact of temperature. Currently, the reference grating method or temperature measurement coefficient correction method is difficult to obtain ideal results. This paper proposes to use a cross-sectionally symmetrical cantilever beam structure as a sensitive element, using the principle of opposite strain and temperature change on the upper and lower surfaces of the cantilever beam, and symmetrically pasting two fiber Bragg gratings on the upper and lower surfaces of the cantilever beam, using the result difference to eliminate the temperature effect and improve the measurement sensitivity. This paper studies the sensing performance of this new type of temperature self-compensated fiber Bragg grating strain sensor, and installs this type of sensor on the anchor of the cable for cable force measurement. The research results show that the developed fiber Bragg grating strain sensor can significantly reduce the impact of temperature and achieve the purpose of temperature self-compensation; using this type of sensor for cable force measurement has high accuracy and sensitivity, which can meet the practical needs of engineering applications.