Selective mass scaling for multi-layer solid-shell discretization of thin-walled structures

The computational burden of an explicit dynamic analysis of thin-walled structures discretized with solid-shell elements can be very high, since the stability condition leads to extremely low time steps because of the small thickness. A selective mass scaling procedure ([1], [2],[3]) can be introduced to overcome this limitation. The technique proposed in [4] for single-layer 8-node solid-shell elements is here generalized to the case of multi-layer shells. The idea is to modify the mass matrix, scaling down the highest structural eigenfrequencies, so that the critical time step is determined only by the in-plane size of the elements, as with standard four-nodes shell meshes. Moreover, the resulting critical time step is shown to be independent of the number of layers used for the throughthe- thickness discretization. The accuracy of the proposed procedure and the computational gain are tested with the aid of numerical examples.