Development And Application Of Wireless Smart Aggregates Structure Health Monitoring System

At present, China is in a period of large-scale infrastructure construction, and concrete structures as the most widely used form in the word, have been widely applied in various types of engineering. During the long service life, because of the inevitable occurrence of material aging and damage, which reduces the reliability of the structure, the structural security issues have been widely concerned. As a kind of effective methods to protect the safety of structure, structural health monitoring (SHM) technology becomes one of the focuses in the field of civil engineering in recent years. The SHM technology which is based on piezoelectric ceramic material has achieved preliminary achievements through scholar researches. However, because of the high cost of signal transmission and the lack of the development of supporting monitoring system, it is not widely used in engineering. Based on the above-mentioned background, the goal of the dissertation is to combine the wireless sensors network technology and piezoelectric ceramic health monitoring technology to build a health monitoring system based on wireless smart aggregate, to meet needs of practical engineering monitoring. The main work of this dissertation includes:(1) To summarize the advantage and weaknesses of the SHM technology which is based on piezoelectric ceramic in the concrete structure, and put forward the goal, the main content and the methodology for the existing problems in this dissertation.(2) To develop a wireless smart aggregate health monitoring node, based on piezoelectric smart aggregates as sensors, by the application wireless radio frequency module, sampling module, power module and the charge amplifier. The developed node can realize the signal data acquisition and transmission function to the gateway through wireless networks, which consists of the basic unit of the system.(3) To develop an active monitoring module, which can monitor the crack of concrete real-timely, and a passive monitoring module, which can monitor dynamic load of concrete structure, based on the theory of piezoelectric wave method. The reliability and stability of the active monitoring module is verified through the concrete beam crack damage experiment, and the reliability and stability of the passive monitoring module is also verified through the internal stress monitoring experiment of reinforced concrete T beam of a bridge under impact loads and the vehicle dynamic weight monitoring test.(4) To develop an SHM system which consists of a laptop and the developed nodes to collect the information of each monitoring node by taking Zigbee802.15.4 protocol as data transmission network, and taking Beedata software as a core platform. The SHM can realize the real-time remote monitoring of the concrete structure cracks, stress and other physical quantities.