Analytical prediction and experimental measurement for mode conversion and scattering of plate waves at non-symmetric circular blind holes in isotropic plates

Abstract

ABSTRACT.A model for guided wave scattering from non-symmetric blind holes in isotropic plates using Poisson and Mindlin plate wave theories for in-plane and flexural wave modes, respectively, is presented. It makes use of the wave function expansion technique and coupling conditions at the defect boundary in order to evaluate the scattered far fields of the three fundamental guided wave modes. The results were compared to other analytical models as well as experimental measurements for mode conversion from S0 to A0. Measurements agreed well with predictions confirming the validity of the model, highlighting at the same time the strong frequency dependence of the scattering and mode conversion behaviour.

Scattering of the fundamental anti-symmetric Lamb wave at delaminations in composite laminates

“…This is different for the case of isotropic materials with a symmetric defect in which the SDP is perfectly symmetric. 9,30,31 It indicates that the SDP of composite laminates is more complicated than that in isotropic materials. The non-symmetric behavior of the SDP is due to the nonsymmetric layup for the upper and lower sub-laminate at the delamination region and the non-symmetric distribution of incident wave amplitude [as shown in Fig.…”

“…Different research activities have been conducted to study the interaction of Lamb waves at different types of damage in various materials. A number of developments [8][9][10] have been achieved for isotropic materials. In recent years, the use of fiber-reinforced composite laminates has steadily increased in engineering applications, such as aerospace, civil, maritime, and automotive, because of their high specific stiffness, light weight, and corrosion resistance as compared with traditional metallic materials.…”

On Accuracy of Analytical Modeling of Lamb Wave Scattering at Delaminations in Multilayered Isotropic Plates

“…A variety of research has been conducted in an effort to improve the understanding of Lamb wave propagation and scattering at defects [5][6][7][8][9][10][11][12] , and to develop innovative techniques for safety inspection of layered materials, such as adhesive and diffusion bonded isotropic plates [13][14][15] and composite laminates 16,17 . Among the developed damage inspection techniques, Lamb wave diffraction tomography (LWDT) 18,19 is proving attractive as it is not only able to determine the existence and location of defects, but can also provide quantitative information from the damage inspection, such as defect sizes and shapes.…”

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

“…Cegla et al [21] presented an analytical model to predict the mode coupling effect of Lamb waves scattering at a circular blind hole. The S 0 and SH 0 Lamb waves were modelled using Poisson plate theory, while the A 0 Lamb wave was modelled using Mindlin plate theory.…”