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In this study, friction-induced vibrations of the window sealing system of a vehicle were investigated using a detailed numerical model. A lumped element, single-degree-of-freedom model was first developed for verification of the numerical procedures. An approximate expression for the frequency of the stick-slip oscillations was obtained. The model indicated that the frequency decreased as the normal force and the difference between the static and kinetic friction coefficients were increased. Stick-slip oscillations were then simulated using a finite element model of a glass run seal using an explicit time marching method. The motion of the seal during the slipping phase was in the direction of the friction force. The peak frequency was found to vary according to the glass position on the seal surface. The results indicated that both the periods of the stick and slip phases of the seal motion affect the frequency of the stick-slip oscillations.

One dominant “wind noise” generating mechanism in road vehicles is the interaction between turbulent flows and flexible structures which include side glass windows. In this study, the effects of seal mechanical properties on the sound generated from flow-induced vibration of side glass windows were investigated. The primary goal was to assess the influence of seal support properties on the noise generated from a plate. Two different models to calculate the optimal support stiffness of the seal that minimizes the velocity response are presented. The results show that both the velocity response and the sound radiation are strongly influenced by dissipation of vibration energy at the edges. It is demonstrate that support tuning can yield significant noise and vibration reduction.

The problem of squealing from vehicle windows opened or closed in partly wet conditions has been investigated. Experiments were conducted using a glass-run seal sample and a tangentially moving glass piece installed on a test bench. The instantaneous velocity of the glass was measured along with the total dynamic frictional force for varying normal static loads and sprayed-water distributions. The characteristics of squeal vibrations and the influence of normal load and water distribution are discussed. The relation between friction force and speed was also investigated. An idealized model consisting of a one-dimensional continuous rod excited by a moving frictional point force was then investigated. The method of averaging was applied to solve the nonlinear equations of motion. The response became unstable when the magnitude of the negative slope and the normal force were large regardless of boundary conditions.