Dynamic and Stability Analysis of the Supercritical Drive Shaft System considering Self-Excited Vibration, Misalignment, and Rub-Impact

The supercritical drive shaft system is widely used in the aviation field. It may experience self-excited vibration, misalignment, and rub-impact during operation, which could change the system’s dynamic behavior and stability. However, the coupling effect of the law of the three is not clear at present. To address this issue, the dynamic equation of the supercritical drive shaft system considering self-excited vibration, misalignment, and rub-impact is obtained, and the stability analysis is derived. The misalignment decreases the rub-impact amplitude and increases the rub-impact range due to the reduced reserve gap caused by the misalignment. The three can undergo coupling when the lubrication state of the spline tooth surface is relatively poor and the misalignment is large. The coupling effect of misalignment and rub-impact excites the unstable region that appears near the critical speed, and this effect would be weakened by the spline damping introduced by the spline tooth friction. The methods and conclusions presented in this paper provide a technical approach for further optimization of supercritical shaft systems.