Impact Echo Array Technique for Concrete Structure NDT: Simulation Studies

Abstract

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.