Static, free and forced vibration analysis of arbitrary non-uniform shells with tapered stiffeners

Abstract

The behaviour of the stiffened plates and shells having varying thicknesses both in the skin, as well as in the stiffening members, has been investigated under various static and dynamic loading conditions by employing a new higher order arbitrarily stiffened triangular shallow shell finite element which includes thickness variations. The shell element can accommodate arbitrary disposition of any number of stiffeners, which in turn allows the irregular mesh generation scheme independent on the alignment of the stiffness in the stiffened shell structures. The quadratic variation of thickness both in the shell elemenl and the stiffeners have been considered. Before carrying out the investigation on the dynamic response analysis in the time domain, the undamped free vibration of the same to compute the natural time period of oscillation has also been performed. A number of problems of bare plates and shells of varying thickness have been analyzed and the comparison of the numerical results with the available theoretical and/or experimental results shows close agreement, even with the coarse finite element mesh scheme. The convergence test with element gridwork refinement for each analysis has also been carried out to show the monotonic and exceedingly rapid convergence. The new results for the above analyses of the stiffened plates and shells, where the thickness is varying for both the plate/shell and the stiffeners have also been presented, which will be valuable for future researchers in this field.