Sensibility study for the near-field sub-band beamforming method for damage detection in bridges

In this work we analyze the performance of a structural health monitoring technique for bridges. The proposed technique employs the use of compactly supported sub-band space/frequency and time/frequency analysis using local vibration characteristics. Moreover, an adaptive beamformer is used to mitigate the effect of the extremely low signal-to-noise ration of the extracted features. The sensor array scans local portions of the structure, providing accurate spatial selectivity and high signal-to-noise ratio for any given scan direction. The sensor array is in direct contact with the structure; therefore, the measured signal is in the near-field of the array, and spherical near-field compensation is necessary. A study of the performance of this algorithm is presented, using different damage scenarios to assess the level of minimum damage identified by the algorithm.