FBG可变灵敏度压力传感器设计

为了实现对压力的多灵敏度状态下监测，设计了一种利用光纤Bragg光栅（ FBG）的可变灵敏度压力传感探头。将裸光栅固定在薄膜片中心与下部外壳之间，传感器探头表面的压力通过薄膜片传递给裸光栅，并可通过灵敏度变换阀改变膜片大小从而改变传感器的灵敏度。对薄膜片进行有限元仿真优化计算，得到其变形特性。薄膜片厚1 mm，工作半径分别调节为10，9，8 cm状态下，最大变形出现在膜片中心区域，在0.1 MPa的表面压力作用下，膜片中心处变形分别为3.875，2.561，1.579 mm，裸光栅固定后，对应的灵敏度分别为：38.44，25.62，15.79 mm/ MPa，实现灵敏度变换。

Design of variable sensitivity pressure sensor using FBG

In order to achieve pressure surveillance in multi-sensitivity state,a kind of variable sensitivity pressure sensing probe is designed using fiber Bragg grating( FBG). Bare grating is fixed between center of thin film sheet and the lower housing. Pressure from surface of sensor probe is transmitted through film sheet to bare grating,and the size of the film sheet is changed by sensitivity switching valve so as to change sensitivity of sensor. Finite element simulation optimization calculation on film sheet is carried out,results in its deformation characteristics. Thickness of the film sheet is 1mm,and working radius is adjusted to 10 cm,9 cm and 8 cm,the maximum deformation occurs at the center of the film sheet under the 0. 1 MPa surface pressure,and the deformation at the center of the film sheet is 3. 875 mm,2. 561 mm and 1. 579 mm. After the bare grating is fixed, corresponding sensitivities are 38. 44 mm/MPa,25. 62 mm/Mpa and 15. 79 mm / MPa,so sensitivity transformation is achieved.