F2008-12-182
Evaluation and Sensitivity Analysis of Tyre and Road Models for the Simulation of Efforts of Commercial Vehicles
Whilst the MBS simulation of the longitudinal and lateral dynamics of vehicles has now reached an easily manageable level the description of high-frequency vibration excitation and its effect on comfort and strength is a greater challenge. In particular for the commercial vehicle sector there is a comprehensive field of activity in this respect. Here it is not only a matter of recording the different service conditions which are completely different compared with those of a car but also of taking into account the structuring of the vehicles based on a modular system and hence with a great diversity of variants. A major priority here is on the adequately precise presentation of the tyre-road contact which forms the decisive excitation mechanism for the motion, forces and stress on the vehicle. This paper considers the process of the evaluation of two suitable tyre models from the comparison with cleat measurements through to the first simulation of the entire model on the virtual road. For the applications desired the FTire model has proved to be a good compromise of computing power, accuracy and parameterisation. Since no suitable testing facilities were available for the identification of the model parameters, in the course of the project an own cleat drum test bench was developed. The initial point of this project was the evaluation of a semi physical and a physical tyre model for their suitability for rough road simulation. Simultaneously an extensive measurement programme has been started for an objective assessment. Due to the fact that test facilities for truck tyres hardly exist, an existing roller test bench was adopted for cleat tests. The next step was a full vehicle simulation of a truck with semi trailer on deterministic and stochastic roads, figure 1. A verification of simulation and measurement has been done again. One focus of this project was the sensitivity analysis of the tyre model to determine the influence of the different tyre parameters. Rough road simulation has been established within the passenger car development. The complexity of trucks is much higher compared with passenger cars due to the fact of the higher kilometre performance, higher number of variants (number of axles, axle bases) and variations of parameter (i.~e. payload). This results in a much higher demand for accuracy in the modelling of the tyre-road contact.
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Session: Chassis