Viscoelastic analysis of composite rotor for pulsed power applications

The time-dependent properties of a composite can result in a significant change of stress and strain profiles in a rotating component over a period of time, which is critical in terms of machine performance and durability. A viscoelastic analysis has been developed to investigate creep and stress relaxation in a multilayered composite cylinder subjected to rotation. The analysis accounts for layer-by-layer variation of material properties, composite fiber orientations, temperature, and density gradients through the thickness of cylinders. A closed-form solution based, on the corresponding elastic problem is,derived for a generalized plane strain state in a thick-walled multilayered cylinder. A Laplace transform is then applied to obtain the numerical solution of the viscoelastic problem. The paper illustrates the derivation of the analytical model and solution, procedure. A numerical simulation shows potential creep and stress relaxation in thick-walled cylinders constructed with graphite/epoxy at an elevated temperature (75degreesC). The analysis can be used to investigate the creep behavior of rotating machines constructed with multilayered components. Accordingly, the performance of a rotating machine over a period of time can be predicted and improved through machine design and material selection.