Analytical and finite element prediction of Lamb wave scattering at delaminations in quasi-isotropic composite laminates

• Published in: Journal of sound and vibration Vol. 331; no. 22; pp. 4870 - 4883
• Main Authors: Ng, C.T., Veidt, M., Rose, L.R.F., Wang, C.H.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 22.10.2012; Elsevier
• Subjects: Acoustics; Delaminating; Exact sciences and technology; Finite element method; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Inhomogeneity; Lamb waves; Laminates; Linear acoustics; Mathematical analysis; Mathematical models; Physics; Scattering; Solid mechanics; Structural acoustics and vibration; Structural and continuum mechanics; Correlation; Thin plate; Surface wave; Modeling; Born approximation; Composite material; Finite element method; Lamb wave; Forward scattering; Wave scattering; Scattering amplitude; Mindlin model; Delamination; Isotropic material; Damaging
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2012.06.002

This paper presents a theoretical and finite element (FE) investigation of the scattering characteristics of the fundamental anti-symmetric (A0) Lamb wave at delaminations in a quasi-isotropic (QI) composite laminate. Analytical models based on the Mindlin plate theory and Born approximation are presented to predict the A0 Lamb wave scattering at a delamination, which is modelled as an inhomogeneity, in an equivalent isotropic model of the QI composite laminate. The results are compared with FE predictions, in which the delamination is modelled as a volume split. The equivalent isotropic model and QI composite laminate are used to investigate the feasibility of the common theoretical approach of modelling the delamination as the inhomogeneity. A good correlation is observed between the theoretical solutions and FE results in the forward scattering amplitudes, but there exists a larger discrepancy in the backward scattering amplitudes. The FE results also show that the fibre direction of the outer laminae has a pronounced influence on the forward and backward scattering amplitudes, which is not predicted by the analytical models.