Critical Velocity Evaluation of Rotating Laminated Composite Doubly-Curved Shells

This research aims to investigate the dynamic behavior of rotating shells. This topic is extremely innovative and deserves to be studied in depth, especially as far as doubly-curved geometries are concerned. In fact, the few papers that deal with this structural problem are limited to singly-curved shells of revolution, such as cylinders and cones. In contrary, the proposed formulation can easily describe the dynamic behavior of shell structures characterized by variable radii of curvature. In addition, a completely general rotating mechanism can be studied, since the angular velocities can be indifferently applied along each principal direction of the three-dimensional space. A combination of more velocity components can be applied as well. A massive set of parametric investigations is performed to evaluate the critical velocities of different rotating structures. This parameter, in fact, is important in shell design, in order to avoid instability phenomena. From the mechanical point of view, several advanced constituents are analyzed, such as laminated and granular composites. The theoretical framework is based on Higher-order Shear Deformation Theories (HSDTs). The solution of the dynamic problem in hand is solved numerically by means of the Generalized Differential Quadrature (GDQ) method, due to its accuracy, stability, and reliability features. The proposed approach is validated through the comparison with the results available in the literature for simpler geometries.