Instability investigation of excited rotating machines connected through a Universal joint mechanism

Using the universal joint is a common way to connect rotating shafts, which are at an angle with each other. However, this mechanical coupling has various advantages, converts a constant input speed to a fluctuating output one. Consequently, this causes resonance in the power transmission systems of vehicles. In the study, the torsional vibrations of drive shafts are considered to investigate the system behavior and the dynamic stability. Herein, the derived mathematical model is investigated by means of the well-known Monodromy matrix method based on the numerical Floquet theory. Furthermore, the acquired results are verified analytically by applying the frequency analysis. In order to examine the influence of each system parameter on the torsional vibrations, the unstable areas at different conditions are identified in detail. The impacts of joint angle, equivalent stiffness, and whole system configuration are investigated numerically. It is found that by increasing the joint angle, new unstable zones appear especially at large angles. Moreover, by changing the joint angle and shafts length, stabilizing the whole system is possible, which can be useful in different conditions and limitations. The presented model is practical to simulate the structural behavior of several two-axis power transmission systems and identify the resonance conditions.

کلیدواژه ها:

Instability ، Joint ، Mechanism ، Rotating machines.