Study on modal characteristics and vibration reduction of an aircraft rotor–stator brake-induced squeal system

Abstract

Based on the modal coupling theory, the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this study. Both the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory mechanism. The unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes place. Then the influences of the contact stiffness, friction damping and frictional coefficient on the brake squeal system are carried out, laying the foundation for the three proposed vibration suppression methods. Results show that the coefficient negative-slope condition will intensify the vibration. Also, a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more conditions. Vibration reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively, while slotting braking stators is invalid in aircraft braking system.