Abstract
Keywords - Load spectrum, load population, statistical driver model, customer behaviour, representative loads
Abstract - The paper introduces a procedure for the determination of representative load collectives for chassis components. It is based on simulations with new vehicle and driver models. These simulation models consider the natural distribution of the properties of driver and road during the life cycle of the vehicle.
The conduct of the driver and the variety of road qualities are analysed in extensive test series on public roads. All driver actions during these test series were stored in statistics differentiating three styles of driving (mild, average, sporty) and four types of roads (city, rural, mountain, autobahn). During the simulation, these statistics are used to create realistic drivers actions taking into account the road type and the load of the car. These actions of the driver and the information of the road surface are transferred to a car model that calculates the wheel forces and moments. The wheel forces can be used to compute the forces on single components of the chassis. A FEM-based durability analysis makes it possible to estimate a damage value.
To solve the problems of calculating speed and storage restrictions a new counting method for the wheel loads, that incorporates the phase relation and the frequency of the wheel loads in all three directions, has been developed. The resulting system of load spectra can be transferred back into a force-time history without any loss of information.
Finally, some possibilities for the use of the simulation results are given. The analysis of the results gives an insight into different customer conducts and their effect on the damage to chassis components.
The represented procedure is to show that, in connection with efficient simulation programs and a new system of load histograms, it is possible to create tools of development even on the basis of relative statements about the durability of components. These can be of great help for the designer and the experimenting engineer as far as important decisions about the practical development are concerned.