Self-excited frictional oscillations of one-mass system with regard to momentary change of velocity sign to opposite one
The frictional torsional oscillations of a one-mass elastic model are considered. The upper section of the elastic element is twisted with a constant angular velocity, but the moment of dry friction forces acts on the lower disk. The dry friction forces are considered to be changed unevenly according to the Coulomb’s law. The relaxation (discontinuous) mode of self-excited oscillations when the disc slip relative to the reference plane alternates with a steady quiescent state is examined. It is assumed that when the disk slips, its angular velocity can instantly change the sign to the opposite one. The analytical solutions for stability zones and the disk slip zones have been obtained for the steady-state self-excited oscillations: the laws of motion, the quiescent state time and the slippage time, the self-excited oscillations period. The conditions for momentary change of the disk’s angular velocity sign to the opposite one have been determined