Influence of body stiffness on vehicle dynamics characteristics

Paper in proceeding, 2016

Body stiffness is one of is one of the characteristics of a passenger car affecting the handling, steering and ride comfort characteristics of the vehicle, but so far only limited aspects of mainly steering and handling has been analyzed. In this paper an extensive and detailed analysis of the influence of body stiffness on steering, handling and ride comfort is performed using a combination of laboratory and track testing of a physical prototype as well as sub-system and full vehicle multi-body simulation and finite element analysis. In this study it is found that the on-center, frequency response and primary ride are mostly affected by changes in body stiffness. For example, the torsional stiffness should be increased in order to improve roll balance in ride maneuvers. It is also found that the front and rear lateral stiffness should be raised in order to reduce dead band and steering wheel angle to yaw rate phase lags. Furthermore, maneuvers that combine handling and ride effects are proven to be particularly useful for defining body stiffness targets related to vehicle dynamics effects and one such maneuver is developed and evaluated in this paper. Finally, it is found that the difference between a rigid and flexibly vehicle model can be up to 13% for certain metrics, meaning that assuming a rigid body can be a significant oversimplification.