Advanced numerical methodology for tyre noise prediction

"It is seen that for lower car speeds the noise generated by internal combustion engine dominates that of tyres and is vice versa at higher speeds. This is beneficiary since a road user can locate an approaching slow car based on the noise from its engine. With the introduction of next generation electric vehicles pedestrian safety will pose a major concern due to the absence of engine and hence its noise. Although artificial noise sources can be added to the car, this however, comes at an extra cost to customer. Although tyres are a second source of inherent noise from the car and several researches have been made on tyre noise, yet there exist no deterministic studies over its efficient design and perception with respect to pedestrian safety. An efficient design of the tyre noise will be an economical solution for a future that demands road safety. In the current work, a design of experiment technique , which involves a simplified and innovative tyre finite element model, is implemented not only to model the tyre dynamic response, but also to correlate the influence of each rubber regions over the tyre overall dynamic behaviour. By employing this numerical model, frequency response functions due to impacts over various treads and positions and corresponding noise transfer functions of a free-free tyre upto 200 Hz is demonstrated using submodelling and sequentially coupled analysis. These results are correlated with the impact noise measurements on the physical tyre treads in a hemi-anechoic chamber. Furthermore, the influence of individual rubber regions of the tyre over the noise transfer function is presented. The damping in the current model is defined as modal damping factors that are determined from the modal tests. In future, the rubber viscoelastic properties are characterised from the tyre dynamic responses from tests and implemented in the simplified finite element tyre model, that can also be used to model the impact noise of a loaded tyre. The major expected accomplishment is to deduce a relation between the generated tyre noise and the perception of it from a pedestrian’s perspective, enhancing the pedestrian safety."