Abstract: Dynamic analysis of hub-beam system with a tip mass is investigated, where the beam is a flexible one. Firstly, by the Hamilton theory and using the finite element method for discretization, the rigid-flexible coupling dynamic model (I.e. the first-order approach coupling model) which takes the second-order coupling quantity of axial displacement caused by transverse displacement of the beam into account is presented. The corresponding dynamic model in non-inertia system (I.e. the zero-order approach coupling model) is presented as well. Then dynamic characteristics of the hub-beam system are studied through numerical simulations. Simulation results demonstrate that small tips mass may affect dynamic characteristics of the system. The tip mass may result in the largening of beam response and the falling of response frequency of the beam, and may affect the terminal positions of the beam and the hub as well. The effect of the tip mass becomes large along with the increasing of angular velocity of the large motion of the system. Even the angular velocity of the large motion is small, the traditional hybrid coordinate model may lead to big error. When the regular velocity of the large motion is large, there possibly exists failure in using the traditional zero-order approach model.

Key words: First-order approach coupling model, Flexible cantilever beam, Hybrid coordinate model, Tip mass