Aspects on Roll and Bounce Damping for Heavy Vehicles 2002-01-3060
This paper presents analytical expressions as well as simulations with a 3D – truck model to study roll and bounce damping for heavy vehicles. The objective is to illustrate the limits in performance resulting from the choice of dampers and mounting positions.
Analytical expressions for a 2D - suspension model show that geometric key parameters controlling roll and bounce damping are damper vertical aligning and perpendicular distance between damper and suspension roll center respectively. In comparison to conventional damper positioning, roll damping for an alternative design may be increased with 75% for the unsprung mass without deteriorating desired bounce motion damping.
Simulations using a 3D - truck model and selected load cases are furthermore used to investigate desired regions of roll and bounce damping. Results show that higher damping generally reduces corresponding motion. The amount of bounce damping is however limited by transient obstacles. For a truck with conventional positioned dampers this results in a roll damping value lower than desired.
The effect from compliance at damper attachment points, from e.g. brackets and bushings, is evaluated with a modified suspension model. Compliance is as could be expected shown to significantly reduce the damping performance. The minimum attachment stiffness necessary for full damper function is derived.