Constraint mechanical model and investigation for rub-impact in aero-engine system

A mechanical model for rub-impact was proposed considering the additional constraints caused by rubbing. Based on the constraint mechanical model, some characteristics of response such as resonant range expansion, contact unstability and amplitude jump during rubbing were studied. The influences of typical parameters on rotor's vibration response with rub constraint were also evaluated. The result reveals that additional constraint stiffness causes the unstable contact range and the resonant range to be wider. While greater friction coefficient between rotor and casing results in smaller response and narrower resonant range. A simplified dynamic model for the aero-engine was built, which takes the constraint effect into account. The numerical simulation result shows that in addition to the resonant range expansion caused by the constraint, the rotor response is also closely related to rubbing location and mode shapes. The rotor response shows a feature of quasi-periodic in slight rubbing, while the rotor motion tends unstable in heavy rubbing.