Self-excited vibration suppression in floating splined rotor systems via a composite spline ring

Floating splined rotor systems with metal splines are susceptible to friction-induced self-excited vibrations under supercritical conditions. To suppress this nonlinear vibration, this paper introduces a novel self-lubricating composite spline design as a replacement for conventional metal splines. The proposed configuration integrates a self-lubricating spline ring between conventional mating internal and external splines, forming a composite structure with two engaging spline pairs (one circular-arc and one involute). A dedicated dynamic model incorporating newly developed spline stiffness and damping formulations is established to give a thorough understanding of self-excited vibration suppression mechanisms. The spline stiffness formulation is derived from deformation compatibility theory and is suitable for both dual-engagement composite spline and single-engagement conventional spline, and the spline damping formulation accounts for both friction-induced damping and material dissipation damping. Comparisons of modal property and dynamic response results validate good accuracy of the proposed models. Both numerical simulation and experimental measurement demonstrate that the composite spline has good self-excited vibration and critical speed resonance suppression capabilities. Intrinsic vibration suppression mechanisms of composite splines are addressed through critical parameter sensitivity analysis. Combinations of higher elastic modulus and lower friction coefficient are desirable for optimal spline ring material selection to enhance suppression performance.