Effects of Imperfect Interface on the Dispersion Curves of Torsional Waves in a Composite Hollow Cylinder

Abstract

This paper investigates the influence of interfacial imperfections on the dispersion relationship of torsional waves in a composite hollow cylinder. The imperfect interface between the inner and outer tubes is modelled by a linear spring interface model, where tractions are continuous across the interface and the displacement jump is assumed to be proportional to the tangential shear stress acting on the interface. The dispersion curves of normalized frequency as a function of normalized wavenumber can be determined by solving an eigenvalue problem. It is shown that for a fixed wavenumber, the modal frequency decreases with increasing interfacial spring compliance, especially for smaller wavenumbers. Besides, at larger wavenumbers, the loss of perfect continuity at the interface has a reduced impact. The thickness effect of the outer tube is further analyzed. The computational results indicate that the modal frequency rises in the case of the thinner coating layer. These torsional wave propagation features may provide insights and guidelines for nondestructive evaluation of composite hollow cylinders with imperfect interfaces. The paper finishes with a summary and concluding remarks.