Inspection of Multilayer Pipes Using Torsional Guided Waves

The use of multilayer pipes has increased recently thanks to their superior mechanical and chemical properties as a replacement of homogeneous single-layer pipes. Therefore, applicable inspections and non-destructive tests for multilayer pipes should be investigated. In this study, the governing equations of torsional wave propagation in the multilayer pipe were initially developed, and the relations between the displacement fields and dynamic stresses in the multilayer pipe were calculated. Then, the dispersion curves and group velocity for the multilayer pipe are plotted according to the boundary conditions. The torsional wave propagation in the multilayer pipe was also simulated using the finite element method via ABAQUS software. By comparing the analytical results and the numerical simulations, a complete agreement was observed between the results. Finally, the influence of effective parameters on torsional wave propagation in two- and three-layer pipes was investigated. The obtained results showed how the thickness, lay-up, and mechanical properties of the layers could affect the velocity of torsional wave propagation in the multilayer pipes.