A Full Spectrum Analysis of a Jeffcott Rotor with Switching Crack in the Presence of Internal and External Damping

摘要

This paper presents the full spectrum analysis of a cracked Jeffcott rotor with the internal and external damping. In this study, a mathematical model is developed for a Jeffcott rotor considering both external and internal damping, crack force, and unbalance force. The crack in the rotor model is considered as switching crack function in the form of a rectangular shape, which provide forces that generate the forward and backward whirls at varied harmonics. The assumption of weight dominance simplifies the switching crack model to a linear one; however, it gives rise to the internal damping due to rubbing on crack faces. The rotor model is numerically simulated to provide responses from two orthogonal directions to obtain the full spectrum analysis to show both forward and backward whirls.