Resonant capture and Sommerfeld effect due to torsional vibrations in a double Cardan joint driveline

Abstract

The dynamics of a system comprising a heavy rotor which is coupled to a motor through a long and torsionally flexible drive shaft with universal joints (U-joints) at its both ends is studied numerically. The U-joints are arranged in Z-configuration to minimize the speed fluctuations between the input and output shafts. It is shown that for large parallel offset between the input and output shafts, Sommerfeld effect characterized by resonance capture and escape through resonance occur. The escape through resonance is associated with sharp jump in speed and reduction in torsional vibration amplitude. In fact, such jump phenomena occur at two different speed ranges, one near the natural frequency of the straight line arrangement of the U-joints and the other at half of that natural frequency. The nature of the dynamic response is affected by the rate at which the input shaft torque or power is varied.