Transient Dynamics of Rotating Flexible Structures-ModeIing

A method for modeling transient dynamics of rotating flexible components is presented. Such dynamic models are of practical importance for both design and control of several engineering applications. Some examples include flexible links of high-speed mechanisms, manipulator arms, airplane propellers, and flexible appendages of spinning spacecraft. This method is based on a nonlinear formulation of the Lagrangian form in conjunction with the finite element techniques. A mixed set of generalized coordinates that accounts for inertia coupling between reference motions and local elastic deformations is employed. Component mode substitution techniques are used for generating a finite set of selected modal coordinates. The formulation accounts for component mode changes due to the effect of reference rotational speed of the elastic component. Base motion excitations, including impulsive forces, are taken into consideration. Numerical results are presented for a beam with its midpoint fixed to a rotating base which is subjected to sinusoidal pulse excitation.