“…The simplifying assumptions can concern the formulation of the equations of motion for thin cylinders [8,9,[45][46][47][48][49] or the approach for solving the partial differential equations by using energetic methods such as Rayleigh-Ritz's [50,51] or Hamilton's principle [46,48,52] and introducing the beam flexural vibrations in the displacements eigenfunctions for thin cylinders [10,14,15,20,21,[45][46][47][53][54][55]. However, despite the simplification, a closed-form solution is not always ensured [48,51].…”