Vibration response of a cracked rotor in presence of rotor–stator rub

Research on vibration response of a multi-faulted rotor system using LMD-based time-frequency representation

“…Darpe [11] applied the signal-based approach for analysis on the vibration response of the rotor system with crack and asymmetry faults together. Recently, Patel and Darpe [2,12] have numerically and experimentally investigated the rotor vibration characteristics of the unbalance, crack, and rotor-stator rub faults, using both classical Jeffcott rotor model and Timoshenko beam element, considering both lateral and torsional degrees of freedom.…”

“…Our primary objective is to investigate nonlinear and non-stationary characteristics of the rotor vibration in presence of multi-faults. This study utilizes the crack model and the rotor-stator rub model presented in [12]. The model of the rotor-stator system thus allows us to investigate the influence of unbalance, crack, and rotor-stator rub on the vibration response.…”

“…Rotor-stator interaction forces are considered at disk location, as shown in Figure 2. The equations of motion for the cracked Jeffcott rotor can be written in fixed coordinate Y-Z system (Figure 1a) as [12] …”

“…Due to this partial opening and closing of the crack, cross-stiffness terms k ξh and k hξ appear in the equations of motion (Equation 1, as k ξh is related to k yz ). However, k ξh comes out to be equal to the k hξ [12]:…”

“…The stiffness coefficients k ξ , k h , and k ξh (k hξ ) is found out from the direct and cross-flexibility coefficients g ξ ,, g h , and g ξh (g hξ ) of the cracked shaft, using linear elastic fracture mechanics theory: Castingliano's theorem, as follows [11,12]:…”