Impact Echo Array Technique for Concrete Structure NDT: Simulation Studies.

This paper simulates an impact-echo array technique for the two-dimensional imaging of defects in thick structures such as concrete. A Finite Difference Time Difference (FDTD) Model was employed for the forward model of the impact-echo method. The absorbing boundary conditions were employed for the efficient modeling of the technique. The signals predicted using the FDTD models from a linear array of impact-echo transmitter-receiver system in a multiplexed configuration was used for 2-D image reconstruction of the cross-sectional region of the structure. The reconstruction algorithm uses time shifting (migration) of the signals based on point-source assumption for the impact sources. The images are represented in a typical “B-scan” representation. Several types of defects were simulated and parametric studies on the different parameters that influence the image quality during imaging of defects in concrete structures were examined. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]