Smart Array Antenna for NDE of FRP-Wrapped Concrete Bridge Members:Final rept. (Jan 2005-Oct 2006)

摘要

This project developed a new nondestructive method for the condition evaluation of fiber-reinforced polymer (FRP) concrete bridge members using small antenna array to detect microwave signals. Work in the initial stage focused on specifications development for frequency range, scan interval, coverage area and other mechanical properties of the proposed antenna system. The configuration and the optimum number of array antennas were also established. The system consists of three modules: a controller and a power supplier, a transceiver, and array antennas with a feed network. An embedded single board computer with a data acquisition board was used as the controller. The design of the power supply was modified to minimize its size. A transceiver with several RF parts was assembled that included filters, power amplifiers, attenuators and detector. The design of the smart antenna system was finalized. The housing design was also improved and refabricated. The software for system operation and real-time data processing and image visualization was developed and integrated with the hardware. The software verified that the feed network was working well and the control parameters were correct. The software program can control the parameters for the transceiver operation and parameters for beam scanning and also diagnose the status of the system. Work in the final stage focused on performance evaluation of the prototype on a variety of concrete-FRP specimens. Debonds of various areas and gaps were artificially created between the FRP and concrete. The prototype was shown to be effective in detecting and even quantifying debonding at the concrete-FRP interface.