Research of vibration characteristics based on a crystal format model of rotor

A rotor is a core component of rotating machinery, but a cracked rotor should seriously threat its safe operation. In order to describe cracks in the rotor conveniently and improve the accuracy of the cracked position comparing with the lumped mass model, a novel crystal format model (CFM) of a rotor system is proposed in the paper. The CFM is made up of crystal grains which are arranged according to the certain rule, and the grain mass and the rotational inertia are considered. Specially, adjoined two crystal grains in the axial direction are connected by a massless elastic rod with a certain bending rigidity, and neighbor two crystal grains in y direction are connected by a massless spring and a torsion spring. The dynamic equations of the CFM are obtained by the bidirectional matrix derivation. The numerical simulations with using the CFM are studied systematically. In addition, the position and depth of a crack can be accurately expressed by the CFM of the rotor system with a breathing crack model and the vibration characteristics are also analyzed. The experimental results fully verify the correctness of the proposed CFM. (C) 2019 Elsevier Ltd. All rights reserved.