Analysis of Guided Wave Propagation in a Multi-Layered Structure in View of Structural Health Monitoring

Abstract

Guided waves (GW) are of great interest for non-destructive testing (NDT) and structural health monitoring (SHM) of engineering structures such as for oil and gas pipelines, rails, aircraft components, adhesive bonds and possibly much more. Development of a technique based on GWs requires careful understanding obtained through modelling and analysis of wave propagation and mode-damage interaction due to the dispersion and multimodal character of GWs. The Scaled Boundary Finite Element Method (SBFEM) is a suitable numerical approach for this purpose allowing calculation of dispersion curves, mode shapes and GW propagation analysis. In this article, the SBFEM is used to analyse wave propagation in a plate consisting of an isotropic aluminium layer bonded as a hybrid to an anisotropic carbon fibre reinforced plastics layer. This hybrid composite corresponds to one of those considered in a Type III composite pressure vessel used for storing gases, e.g., hydrogen in automotive and aerospace applications. The results show that most of the wave energy can be concentrated in a certain layer depending on the mode used, and by that damage present in this layer can be detected. The results obtained help to understand the wave propagation in multi-layered structures and are important for further development of NDT and SHM for engineering structures consisting of multiple layers.

Propagation of Non-Linear Lamb Waves in Adhesive Joint with Micro-Cracks Distributing Randomly

“…where 3) . Considering the free surface condition of the upper and lower surface for the tri-layer structure, the following equation can be obtained, according to Equations (1)-(3):…”

“…It is based on the principle of linear acoustic physics, including transmission, reflection, scattering, and absorption of the acoustic energy. For example, Lugovtsova et al [3] analyzed the propagation of guided waves in a plate consisting of an isotropic aluminium layer bonded to an anisotropic laminate made of carbon fibre reinforced plastics. Their results show that most of the wave energy can be concentrated in a certain layer depending on the mode used, and damage presenting in this layer can be detected.…”

Lamb Wave Scattering Analysis for Interface Damage Detection between a Surface-Mounted Block and Elastic Plate

“…However, the computational costs related to three-dimensional simulations are much higher compared to those of two-dimensional mathematical models, which can be also very efficient for damage detection. For instance, two-dimensional simulations were used to simulate Lamb wave excitation and sensing by rectangular PWATs in an elastic plate with a rectangular elastic obstacle bonded on the surface of the plate [ 26 ] and to estimate the properties of guided waves [ 27 , 28 , 29 ].…”

A Combination of the Scaled Boundary Finite Element Method with the Mortar Method

“…Especially in the frequency domain, the Scaled Boundary Finite Element Method reduces the approximation dimension because only degrees of freedom associated with the boundary of a polygonal element are required. Those desirable properties make the method particularly suitable for simulating the dynamic response in bodies with cracks, as is essential for many non-destructive testing and structural health monitoring applications [17,18].…”