Non-Destructive Evaluation of Elastic Targets Using Acousto-Electromagnetic Wave Interaction and Time Reversal Focusing

The objective of this research is to demonstrate the efficacy of using acoustic and electromagnetic (acousto-EM) wave interaction and time-reversal focusing in the non-destructive evaluation of an object. Acousto-EM wave interaction occurs when an electromagnetic wave scatters from an object under seismic or acoustic illumination; the acoustic vibration of the object gives rise to a frequency modulated scattered electromagnetic field which is a function of the object and both the electromagnetic and acoustic source parameters. A recently developed model, which is capable of predicting the first Doppler component of the frequency modulated scattered field for arbitrary two-dimensional objects over a wide bandwidth, is used in the analysis. Time reversal focusing is also used to improve sensitivity and obtain information about the location of flaws within the target. Both the unshifted electromagnetic fields scattered from the stationary target and the Doppler component are analyzed. The sensitivity of the Doppler component to the presence of flaws, which perturb the mechanical mode shape and resonance frequency, is demonstrated for application in non-destructive evaluation.