Motion behaviour of ball joints in automotive chassis with respect to structure-borne sound

The dynamic properties of automotive chassis are affected by several different factors. Especially with respect to transmission of structure-borne sound, flexible bearings in chassis play an important role. In contrast to elastomer bushings, friction afflicted ball joints have not yet been studied with regard to this specific aspect [1]. In order to analyse their dynamic properties, a component test bench was developed, which is used to measure the rotational motion behaviour of ball joints in-depth. Based on vehicle test runs, a specific excitation range was defined to meet realistic boundary conditions for the experimental examinations. The experimental results show conditions of sticking and sliding due to specific operating states depending on low frequency vibrations. These results form the background of the ball joint model. In this context, the biggest challenge is to describe the nonlinear component characteristics in time domain simulation. To identify parameters and to improve the understanding of mechanisms in moving ball joints, a numerical model approach was further developed which considers nonlinear effects. The comparison of experimental and simulation results show the ability of the model to calculate the ball joint behaviour in time domain simulation. Figure 1.1 shows the structure of the used approach.