ELASTIC-WAVE PROPAGATION IN A TIMOSHENKO BEAM SPINNING ABOUT ITS LONGITUDINAL AXIS

Elastic wave propagation in a circular Timoshenko beam rotating about its longitudinal axis is studied. Gyroscopic effects are included. Bot h infinite and simply supported finite beams are treated. The characte ristic frequency equation for harmonic wave propagation is determined in the case of an infinite beam. Results are presented for the frequen cies and group velocities as functions of the wave number. As expected , the beam's rotation bifurcates each wave velocity branch of the non- rotating beam into two. Transient wave propagation in a simply support ed finite beam subjected to a simulated transverse impulse is treated using multi-integral transform techniques. Numerical results are given for the direct and gyroscopically induced components of the beam's di splacement as functions of time and position. A significant finding is that the out-of-plane displacements can grow to be of the same order of magnitude as the in-plane displacements.