Development And Application Of Fiber Acceleration Sensor To Check Floor's Vibration Caused By Human Walking Stimulation

With the continuous improvement of the comfort requirement of building structure,the problem of vibration comfort has been paid more and more attention.Due to the low stiffness of the large span building system,the first order vertical self-vibration frequency of the floor is low.It's easy to generate a large vibration under the excitation of the pedestrian load,thus affecting the user's comfort.Because of the low sensitivity and poor anti-interference ability of traditional electric accelerometer,it is difficult to meet the increasing demand of vibration monitoring precision.This paper takes the vibration detection of floor vibration caused by pedestrian load as aim,a new optical fiber grating acceleration sensor is designed and developed by FBG with high sensitivity and high resistance to electromagnetic interference.The details are as follows:(1)Introduce the significance of displacement monitoring in engineering structure,and the development and research of the vibration monitoring of large-span roof and the acceleration sensor of fiber grating are described.(2)Introduce the sensing principle of fiber grating and the theory of vibration of floor slab,and describe the structure,classification and sensing principle of optical fiber and the dynamic characteristics of floor slab in detail.(3)Describes the design principle of the sensor and the determination of the material and size of the sensor and the processing and assembly process of the sensor.Moreover,study the sensor is calibrated,and the frequency response and sensitivity of the sensor.(4)Describes the application of the sensor to the actual monitoring and the performance of the sensor based on the long corridor of Kangping high school and Shenyang Jianzhu university.In this paper,we design a sensitivity adjustable fiber grating acceleration sensor based on the previous research results,and this sensor is especially suitable for the acceleration monitoring of floor vibration caused by the pedestrian load.We use the L-type rotary shaft structure,it can effectively reduce the lateral interference of the sensor.And the sensor's mass block has three gears that can slide to adjust sensitivity and range,the working range of sensor is 17Hz?20Hz and 25Hz,and sensitivity is 27.703pm/ms-2?17.569pm/ms-2 and 7.761pm/ms-2 respectively.The conclusions are drawn from two test cases:The sensor has high sensitivity and strong ability of anti-interference,which fully meets the monitoring demand of floor vibration caused by pedestrian load.