3D sloshing frequency analysis of partially filled cylindrical laminated composite containers

A 3D finite element approach is presented for the free vibration analysis of partially filled cylindrical composite containers, emphasizing direct coupling between a flexible composite container and fluid sloshing. For the motion of small amplitude, the fluid is assumed to be inviscid and linearly compressible. The fluid domain is modelled based on the Helmholtz wave equation, derived from the Navier-Stokes equation, using 20-noded brick elements. The structure domain is modelled by using the degenerated solid elements based on Reissner-Mindlin assumptions. Thus, in terms of mid-surface nodal variables, the 3D field has been reduced to a 2D field by taking into account shear deformation and the rotating inertia effect. A direct coupled analysis is performed for the fluid-structure interaction to obtain a coupled response. A MATLAB code has been developed, and the results have been validated with results available in the open literature and found to be in good agreement. Results from the parametric study indicate the significance of ply orientations and a dimension ratio of the composite container while finding the coupled sloshing frequencies of the coupled system.