Effects of damper failure on vehicle stability

Abstract

The general approach in vehicle dynamics analysis is to use mint state characteristics of the chassis components in vehicle simulation models. However, some of the chassis components are vulnerable to damage which might induce drastic changes in component characteristics. A comprehensive vehicle stability analysis should, therefore, account for the changing characteristics of the components. In the literature, such analyses exist only for slowly-developing damper wear cases. In recent years, there has been an increase in the popularity of controlled dampers. These dampers include an increased number of structural elements and their characteristics depend on the control current supplied by a complex control system. In this study, the effect of sudden shifts in controlled damper characteristics on the stability of the vehicles is examined in detail. Two different types of damper-characteristic shifts are taken into account; the first one is a soft-to-hard transition that takes place due to control current cut-off and the other is a hard-to-soft transition originating from failure of the mechanical components in the damper. A detailed vehicle simulation model is developed, verified and used to simulate different driving manoeuvres where damper failure might affect vehicle stability. The analysis is extended to a vehicle configuration employing a simple ESP structure in order to observe the effects of chassis control systems in minimizing the effects of the damper failure. The results obtained in this study show that the failure of a damper might lead to vehicle instability in some critical driving situations for vehicles lacking advanced chassis control systems.