Torsional Vibrations of Rotating Cardan Shaft Systems

Manipulating Cardan couplings is a widespread technique to link shafts, where shafts are not aligned and at an angle with each other. Although, this mechanical joint has various ad-vantages, 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 driveshafts are considered to investigate the system behavior and dynamic sta-bility. Herein, the derived mathematical model is investigated by means of the Monodromy matrix method based on the famous Floquet theory. Furthermore, the acquired results are ver-ified 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 condi-tions and limitations. The presented model is practical to simulate the structural behavior of several two-axis power transmission systems and identify the resonance conditions.