Vibrations of complex shells of revolution using B-spline finite elements

This paper presents and evaluates a local-global B-spline finite element method for the modal analysis of joined thin shells of revolution, Each shell component is modelled by a super element. For smooth meridian, local displacements of the shell middle surface and their first derivatives are matched at the junction. However, for discontinuous shells, the C-1 continuity of tangential displacements is relaxed and a local to global frame transformation is applied for normal and longitudinal displacements. The super element formulation in local-global frame reference and the minimum number of degrees of freedom (three nodal displacements augmented by the bending rotation at the joints only), provided by the uniform cubic B-spline interpolation, are the main originalities of the present work. Efficiency and accuracy of the proposed technique are evaluated through various well known two-branch shell combinations. Results are compared to analytical, experimental and numerical solutions found in the literature. A very satisfactory behaviour of the approach was observed. (C) 2000 Elsevier Science Ltd. All rights reserved.