Chaotic search algorithm for detection of discontinuities using guided waves and beamforming data

Abstract

The goal of inspection and continuous health monitoring of engineering structures is to detect defects particularly during their early stages of development. In this work, a method using an optimization scheme for localization of a target using ultrasonic guided waves in a thin plate and data sampled from a beamforming is studied. The proposed optimization scheme finds the target by using a search algorithm based on random and chaotic walk search to reduce the number of evaluation points within the search space. The data used for the scheme is extracted from the using only a reduced number of evaluation points from the energy reconstruction map of a delay and sum beamforming algorithm. The proposed approach is numerically studied and implemented experimentally for discontinuity detection in a plate using guided Lamb waves. The combined experimental and numerical analysis indicates that the searching algorithm was able to find an acoustic target generated by a discontinuity in a plate even when the signals were contaminated by noise.