微型布拉格光栅土压力传感器的设计与试验

Design and Test of Micro Bragg Grating Soil Pressure Sensor

基于金属膜片受压径向拉伸特性。依据土压力传感器与土介质的匹配原则,设计了一种微型布拉格光栅土压力传感器。传感器充分利用金属膜片受到外界压力而产生的最大应变。传感器理论压力灵敏度为2.337 6 nm/MPa。用ANSYS建立金属膜片有限元模型,提取膜片中心点径向位移,得到仿真灵敏度为2.332 0 nm/MPa。用台式气压源、光纤光栅解调仪等设备组建气压标定平台,对传感器进行标定试验。试验表明,在0.3~1.0 MPa范围内,压力灵敏度为1.962 9 nm/MPa,较裸光栅提高654倍,线性度为99.4,具有低啁啾、稳定性高的特点。

Based on metal diaphragm＇s radial tensile properties and according to the principle of matching the soil medium and the soil pressure sensor,a miniature Bragg grating soil pressure sensor was designed. The sensor leveraged the metal flake by external pressure resulting from the maximum strain. The theoretical pressure sensor sensitivity was 2. 337 6 nm / MPa. Using ANSYS to build up the finite element model of metallic flake could obtain the result that the model＇s pressure sensitivity was2. 332 0 nm / MPa by extracting the radial displacement of the flake＇s center. Using the pressure calibration platform which was formed by a desktop air pressure source,fiber grating demodulation instrument and other devices could calibrate the sensor. In the measurement range of 0. 3 ~ 1 MPa,test shows that the sensor＇s pressure sensitivity is 1. 962 9 nm / MPa,representing an increase of 654 times than bare grating. Its linearity was 99. 4%. The sensor has characteristics of low chirp and high stability.