Abstract
The paper analyzes the influence of nonlinear (cubic) internal damping (in the Kelvin–Feucht model) and cubic nonlinearity of elastic forces on the dynamics of a rotating flexible shaft with a distributed mass. The shaft is modeled by a Bernoulli–Euler rod using the Green function, the discretization and reduction of the problem of rotating shaft dynamics to an integral equation are performed. It is revealed that in such a system there is always a branch of limited periodic movements (self-oscillations) at a supercritical rotation speed. In addition, with low internal damping, the periodic branch continues into the subcritical region: when the critical velocity is reached, the subcritical Poincare–Andronov–Hopf bifurcation is realized and there is an unstable branch of periodic movements, below the branch of stable periodic self-oscillations (the occurrence of hysteresis with a change in rotation speed). With an increase in the internal friction coefficient, the hysteresis phenomenon disappears and at a critical rotation speed, a soft excitation of self-oscillations of the rotating shaft occurs through the supercritical Poincare–Andronov–Hopf bifurcation.