MODELLING AND ANALYSIS OF ROTATIONAL STEERING VIBRATION FOR SUV USING MULTIBODY DYNAMICS TOOL.

Steering vibration is a major NVH issue that affects overall NVH comfort in passenger cars. There are two types of fundamental steering vibrations [1]:

• Vertical/lateral translational vibration
• Rotational vibration (Focus of this study)

Many studies of mechanisms contributing to steering wheel nibble have been carried out in the past. An overview of stimulation sources (disturbance factors) to steering nibble like wheel imbalance mass is given. As an example of the controversial aspects of the problem, this paper deals with the assumption of suspension compliance characteristic and its conflict with the observed transfer of vibration caused by small (realistic) amounts of imbalance or tyre force variation. The tyre imbalance is virtually created by adding small mass on front right wheel. After modelling and correlating the full vehicle in ADAMS/car, it is possible to identify a natural frequency that contributes reasonably to the nibble phenomenon in the steering wheel. Based on this model, a CAE study on parameter sensitivity, using the design of experiments' approach, is presented.

A correlation with experimental results for K&C for front suspension subsystems is also presented.