Bridge Structural Health Monitoring System Integration Using Wireless Sensor

With the recognition of structural safety and the development of monitoringtechnique, Structure health monitoring (SHM) has already become a research hotspot inthe field of engineering structures. Most existing SHM implementations use wired dataacquisition systems to collect vibration data from various locations in the structureinduced by ambient sources for analysis. In recent years, low-cost wireless sensors haveemerged as an enabling new technology to avoid the high cost of traditional genericwired systems for structural monitoring applications. This dissertation combineswireless sensor technology with structural health monitoring technology which studiesthe hardware module of the wireless smart sensor node and develops related applicationprograms. A wireless data acquisition system applied to monitor structural vibrationsignals has been designed and performance of the system has been tested throughexperiments, which reveals the bright future of wireless sensor network.First, in this dissertation, acceleration sensor ADXL335has been choosed as thesmart sensor chip according to the demand of acquisition high precision vibration signalfor structural health monitoring. Circuit design of the sensor module and the wirelesssmart sensor board fabrication are both achieved. Combining with IRIS mote which isthe fifth generation of MICA series, the sensor drive program and wirelesscommunication program have been compiled in nesC language based on TinyOS. Also,serial communication between base station and PC is completed by using of LabVIEWDevelopment Tool. All of the above integrate a wireless acceleration acquisition systemwhich achieves the high precision demand of the acceleration signal acquisition.Then, time synchronization signal acquisition of wireless data has been deeplystudied. Several kinds of time synchronization method with their merits and demeritsare provided in the dissertation. In order to achieve the demand of time synchronizationin structural vibration monitoring system, time synchronization configuration withFTSP algorithm of micro-seconds lever has been designed. Tests of the timesynchronous error were carried out using the IRIS mote.Finally, the wireless vibration testing platform was developed in laboratory.Performance of wireless smart sensor node and the acquisition system were testedwhich can get the modal parameters of bridge model. Comparing with wired data acquisition system, the result verifies that wireless acquisition system can identifystructural dynamic characteristic parameters accurately, which proves the feasibility andits good performance of structural vibration system monitoring based on wireless sensornetwork.