Numerical investigations on a new method for reconstruction of baseline signals for damage detection with Lamb waves

Abstract

Guided wave-based damage detection techniques have received a lot of attention over the past two decades. Majority of the techniques utilise baseline subtraction approach to detect presence of structural damage. In this approach, the baseline signal previously recorded for a healthy-state structure is subtracted from the actual signal during routine inspections. A significant deviation between these two signals is treated as the presence of a critical damage. However, the accuracy of this approach can be significantly compromised by various uncontrolled factors affecting wave propagation, which include temperature changes, degradation of mechanical properties of PZT, adhesive bond or the structure itself. This paper presents the numerical investigations on a new method to reconstruct the baseline signal, which aims to incorporate the aforementioned variations. The proposed method is based on the latest advances in 3D laser vibrometry in conjunction with high-fidelity FE simulations of guided wave propagation. The current paper describes the numerical implementation of this new method for both beam and plate-like structures.