Fractal dimension–based Lamb wave tomography algorithm for damage detection in plate-like structures

Abstract

This study presents a new signal-processing technique that utilizes the fractal proprieties of guided ultrasonic waves for structural health monitoring in complex structures. In particular, we use the fractal dimension of Lamb waves as a damage-sensitive feature. In the last decade, a fractal analysis has been extensively used in image analysis problems, especially in the medical field. In this article, a damage index based on the fractal dimension of Lamb waves is proposed using a modified box-counting algorithm. The proposed damage index has been also combined with a tomographic imaging algorithm to identify damages in plate-like structures. The performance of the proposed approach is validated through experimental tests performed on an aluminum plate instrumented with eight circular piezoelectric (lead zirconate titanate) transducers.