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Region of Interest Identification for Damage Detection via Sub-Band Near-Field Beamforming and Symmetric Arrays

The near-field sub-band beamforming method for damage detection is a technique that addresses some inherent problem in current and past methods for damage detection in civil structures. It has been shown that the above mentioned algorithm is able to provide an approximate space/frequency localization of a damaged region in a simulated structure. This is accomplished by subband energy comparison among scanning directions, using a reference signal from the pristine system. To move towards a more usable algorithm, we need to eliminate the need for the reference measurements, and operate with only one set of data. In this paper we describe the first theoretical step to achieve this goal using two symmetric sub-arrays to identify Regions-Of-Interest (ROI) of the structure at the crossing points of opposite scanning directions. Moreover, an analysis on the effect of damage on the spectral signal from a simulated FE structure is used to help understand how the strain on the physical parameters of the system impacts the response of the structure.