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Keywords:

finite crack, Absorption, waves, Acoustics, Computer Simulation, scattering, conversion, Manufactured Materials, interface, Materials Testing, Models, Chemical, velocity, solids, Radiation Dosage, Radiometry, layer, Rubber, Steel, Vibration, Science & Technology, Technology, Engineering, Electrical & Electronic, Engineering, FINITE CRACK, WAVES, SCATTERING, CONVERSION, INTERFACE, VELOCITY, SOLIDS, LAYER, 02 Physical Sciences, 09 Engineering, 40 Engineering, 51 Physical sciences

Abstract:

A theoretical study of Lamb mode propagation through an absorptive bilayer consisting of a steel plate coated by highly absorptive rubber with a finite delamination dividing these layers is presented. Essentially, in such a bilayer structure, steel-like A0 and S0 modes still propagate, although with moderate absorption. Two different types of delaminations are taken into consideration: slip delaminations in which noncontact boundary conditions are assumed only for shear displacement and stress, and stress-free delaminations in which noncontact boundary conditions are assumed for all mechanical displacements and stresses. The calculations, which are based on a modal decomposition method, show that delaminations in absorptive bilayers result in a considerable change of the normal displacement amplitude at the bilayer surfaces inside the delamination region, and for an incident mode steel-like A0 mode, also in the transmission region. Stress-free and slip delaminations can be distinguished exploiting their different effect on the steel-like A0 and S0 incident modes.