Computer Simulation of Driveline Vibration Due to Universal Joints in Heavy and Medium Duty Trucks

TORVIB is a general purpose program which provides a quick, complete torsional analysis of the many unique drivelines specified by truck customers. This program has been recently modified to include universal joint effects. In the updated program, finite element methods are used to calculate maximum vibration angles, maximum vibration torques, and secondary couples caused by dynamic engine torques and universal joints. The techniques of modeling universal joint effects which are described in this paper can also be used to analyze drivelines with commercial finite element software.

Universal joint effects were added by first updating the mass and stiffness matrices to include degrees of freedom at each yoke on a universal joint. Rotational constraint equations were then written for each universal joint and applied using the large stiffness method. Finally, post-processing calculations were added to recover the secondary couples at each yoke.

This method of modeling universal joints was compared with results obtained from general purpose dynamic simulation software. The results showed good agreement.