Experimental validation of Lamb wave dispersion curves using the Scaled Boundary Finite Element Method (SBFEM)

Dispersion curves are essential for characterizing Lamb wave propagation. A key challenge in estimating these curves is ensuring both computational efficiency and agreement with experimental results, particularly in complex, multilayered materials. This study focuses on bilayer structures, specifically metallic substrates with viscoelastic coatings, and employs the Scaled Boundary Finite Element Method (SBFEM) to generate dispersion curves. SBFEM discretizes the waveguide cross-section using high-order spectral finite elements and a Gauss–Lobatto–Legendre (GLL) node distribution, assigning a single spectral element per material layer. To validate the SBFEM curves, estimation is compared with experimental data obtained from metallic plates and bilayer structures consisting of viscoelastic coatings on steel substrates. The strong correlation between numerical predictions and experimental results highlights the effectiveness of SBFEM in accurately capturing Lamb wave behavior in bilayer waveguides with viscoelastic coatings while maintaining computational efficiency. These findings reinforce the method’s applicability for the analysis of wave propagation in complex, layered, and dissipative materials.