Article Article
"Simulated Transient Electromagnetic Response for the Inspection of GFRP-Wrapped Concrete Cylinders Using Radar NDE"

Assessing the subsurface condition of glass fiber reinforced polymer (GFRP)-retrofitted concrete structures is an important inspection problem for the maintenance of reinforced concrete structures retrofitted with high performance composites like GFRP. The objective of this paper is to investigate the radar response of GFRP-concrete cylinders through a parametric study, using the finite difference time domain (FDTD) method. Intact and artificially damaged GFRP-wrapped concrete cylinders were modeled in a two dimensional domain. Considered parameters include the thickness of GFRP wrap=layer, width and depth of artificial defects, and the incident frequency. Modulated Gaussian signals with a carrier frequency ranging from 8GHz to 18GHz were used as the incident wave. Field and power responses in both time and frequency domains were investigated. A nonlinear effect due to the variation of defect dimensions is found in both time and frequency responses, indicating the multiple, interlayer scattering effect in the system.

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