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Transport system safety is clearly one of the most important social problems and involves a lot of items, such as road, tyre and vehicle design. VERT Consortium (EC funded Project BRPR-CT97-0461), including ten partners from six different European countries, has faced this problem in the last three years implementing in ADAMS Environment a full vehicle model focused on tyre/road interaction in presence of water, snow and ice. Such a model has been finally exploited in order to detect the most dangerous situations and to define guidelines for the optimised design of new “safer” products (tyres, vehicles and roads). This paper presents a general overview of VERT activities and achievements.

A new Tyre Model suitable for Tyre Dynamic Representation on uneven road and in general high-frequency handling excitations has been developed in a multi-body code. The tyre representation is both empirical and physical: contact forces between contact patch and road are achieved from numerical Pacejka formulation but applied to a physical structure representation instead of to a simple spring-damper element. Such a physical tyre model enables the simulation of the dynamics up to 100 Hz and vibration due to high frequency handling manoeuvre or on uneven road contact excitation. Validations with experimental results are of course included both for tyre tests on suitable testrigs and for full vehicle manoeuvres.

This paper describes the modeling, experimental procedures and validation process used for a bus model in ADAMS/Car. It is described the bus subsystems which have been generated by ADAMS/Car templates. A comparison of experimental results and model simulation for an ISO lane change at 80 km/h and a sweep steer at 40 km/h with steering wheel imposed motion are made. Some of the quantities ilustrated are: steering wheel angle, lateral acceleration and yaw rate. Frequency domain analysis was made and the yaw rate and lateral acceleration gains and phases due to steering wheel angle were plotted. Finally, a comparison is made between ISO lane change with imposed motion versus a machine control (driver) with varying driver parameters.

This paper introduces and discusses a new 2D physical model which has been developed and validated in order to study and optimize the handling behavior of the tire. It can be divided into two parts, the structural model and the contact area model. The parameters, that are function of the vertical load, are identified or calculated by comparison with the results provided by 3D finite element models. The input data for the identification procedure consist of a set of frequency responses performed on the finite element model. A second set of simulations on the 3D model of the tread pattern gives the characteristics of the contact model. Once built the 2D model it is easy to carry out both steady state and transient analysis. The steady state analysis returns the cornering carpet, in terms of lateral force and self-aligning moment as function of the cornering angle. The transient analysis allows the evaluation of the relaxation length and dynamic characteristics.