温度解耦增敏式光纤光栅应变传感器

飞机载荷参数测试对保障飞行安全至关重要,光纤光栅传感器凭由诸多优势在不断尝试应用在其中。为了实现对结构应变的精确测量,同时排除温度带来的影响,通过对基底及光栅刻写工艺的特殊设计,实现了温度解耦增敏式光纤光栅应变传感器,并对基底进行有限元分析。在10~60℃的温度范围内,该新型传感器温度灵敏度为45pm/℃,较裸光纤光栅增敏4.5倍,线性度良好。在MTS拉伸试验机上测试拉伸试验件在0~700με条件下传感器特性,灵敏度为1.46pm/με,较裸贴方式增敏1.4倍,线性度良好。传感器温度误差小于0.1℃,应变误差小于3με。实验结果表明,传感器解耦性能良好,与理论分析相符,满足飞机载荷谱测试的应用背景。

Temperature decoupling and high strain sensitivity fiber Bragg grating sensor

Aircraft load parameter testing is essential to ensure flight safety. Fiber grating sensors with several advantages are continuously being developed in the constant attempt to apply them in aircraft load parameter testing. To achieve accurate measurement of structural strain and exclude the effects of temperature, we developed high strain sensitivity and temperature decoupling in a fiber Bragg grating sensor via the fiber grating engraving process. Furthermore, we employed finite element analysis to develop special designs for the substrates. In the temperature range of 10-60℃, a temperature sensitivity of 45 pm/℃ was achieved for the new sensor that is 4.5 times higher than that of bare fiber gratings. In addition, good linearity was obtained. The sensor characteristics of the test systems were investigated using an MTS tensile testing machine under microstrains ranging between 0-700 με. Good linearity and sensitivity of 1.46 pm/με were obtained, the latter being 1.4 times higher than that obtained using surface adhesion method. The temperature and strain error of the sensor are observed to be less than 0.1℃ and 3με, respectively. The experimental results confirmed the satisfactory temperature decoupling performance of the sensor that is consistent with theoretical analysis. Thus, the sensor can be used in aircraft load spectrum tests.