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Wave conversion process in lightweight structures: diffusion through defects in the transition bandwidth

Book Contribution - Book Chapter Conference Contribution

Structural waveguides involving heterogeneous cross-sections or based on periodic patterns are often subjected to wave conversion phenomena. This paper is concerned with a specific type of conversion observed in sandwich structures called bending-to-shear conversion. It occurs in the ”transition” bandwidth, where the flexural wave is partially localized in the core of the sandwich, hence mainly governed by its shear modulus. This conversion has consequences on the wave reflection characteristics through a defect’s interface. The need for wave-based Structural Health Monitoring strategies providing sub-wavelength detection capabilities has been increasing with the development of advanced, often periodic lightweight components. It is therefore advantageous to predict and take into account conversion effects at the earliest design stage of SHM systems. This paper explores the consequences of such conversions on the reflection coefficient of flexural guided waves in lightweight structures. A Diffusion Matrix Method (DMM) is employed to estimate the diffusion of guided waves obtained using refined unit-cell FE models. Case-study is a composite sandwich waveguide with honeycomb core. Results show significant variations of the wave’s sensitivity to small-scaled core defects and delaminations during the conversion process
Book: Proceedings of the 2nd Euro-Mediterranean Conference on Structural Dynamics and Vibroacoustics
Pages: 208 - 211
Publication year:2017
Accessibility:Open