THE EFFECT OF TYRE MODELS ON THE STABILITY AND RIDE DYNAMICS OF TWO-WHEELED VEHICLES: MF-TYRE VS. MF-SWIFT

In the simulation of road vehicles dynamics, the tyre model should be tailored to the type of analysis. For stability and ride analyses, the MF-Tyre model is the most common choice, which is considered reliable up to 8-15 Hz. Forces are generated from tyre slips and normal load, the carcass dynamics are neglected, the lagged-response is accounted using relaxation equations or spring/damper elements. The MF-Swift model is another well-known option, this tyre model builds upon the MF-Tyre by including a rigid ring in order to simulate the carcass dynamics and extend the validity range up to 60-100 Hz. The aim of this work is to assess the effect of these two different tyre models on the stability and ride dynamics of two-wheeled vehicles. The lateral stability is investigated through the analysis of weave and wobble vibration modes. The ride response to impulses is investigated through wheelie/stoppie manoeuvres and with the vehicle running over a cleat, while the response to pseudo-random excitations is investigated through simulations on rough ISO roads. It was found that the carcass dynamics have some impact on the lateral stability. Conversely, the carcass dynamics have an impact on the in-plane responses at high frequency, both to impulsive and pseudo-random excitations.