The LabVIEW Based Distributed Optical Fiber Sensing System For The Concrete Bridges

The life-span of large infrastructure projects such as bridges is relatively longand the idea of bridge health monitoring has been proposed for a long time. In recentyears, the increase of the bridges collapse brings huge economic losses to the state andpeople, so more and more attentions have been paid to the security of the bridges.This paper introduces and discusses the headway and the developing direction ofthe distributed optical fiber sensing technology, and then analyzes and compares thehot spots in the sensor technology to establish the direction of research. Thedistributed optical fiber sensor based on Brillouin scattering is a novel optical fibersensor technology. Because of many advantages such as large dynamic range, longsensing distance, high spatial resolution and accuracy, and it has been the focus andleading edge topics in the optical fiber sensing field in recent years.This paper makes a brief to Brillouin scattering phenomenon in the optical fiber,and makes a description that the Brillouin frequency shift will change when the fibermaterials are affected by the temperature or strain. After introducing the Brillouinscattering mechanisms, this paper calculates and analyzes the linear relationshipbetween the Brillouin frequency shift, strain and temperature, which as the theoreticalbasis of the Brillouin scattering distributed optical fiber sensing technology.Based on the results of previous studies and referring to the relevant literatures,this paper compares the two methods on the direct detection and coherent detectionBrillouin scattering signal, brings forward the design of optical fiber Brillouin sensingsystem based on microwave heterodyne technique, and analyzes the signal detectionprinciple, preferences and the system performance in the system.At last introduces the characteristics of the virtual instrument and the LabVIEW,and makes a design of the data collection procedures, data processing and data displayprogram based on HS3-100data acquisition card collection, realizing the design of themicrowave heterodyne Brillouin sensing system based on the LabVIEW to analogsignal transmission in the system through the development of VI programs.