FREE AND FORCED VIBRATIONS OF A SPINNING VISCOELASTIC BEAM

The free and forced response of spinning, viscoelastic, Rayleigh shaft s is studied. Viscoelasticity is included using the three parameter so lid model. The closed from polynomial frequency equation and integral expressions for the response to a general forcing function are derived . A convenient decay parameter is described. Results are given for nat ural frequencies and decay rates as functions of shaft rotation speed, stiffness, and viscosity. It is found that shaft materials are possib le which have desirable damping and natural frequency characteristics. A parameter case is discussed in which natural frequency and damping simultaneous increase, while stiffness is held constant. Also, the spe cial case of forced response to a step load is derived and used to ill ustrate the combined effects of viscoelasticity and gyroscopic forces.