Several state of the art papers and even books on brake vibration and/or noise have been presented in the literature. Many of them have analytically and sharply accounted for the impressive amount of research undertaken on this topic. This state of the art review focuses on the still-open questions that appear crucial from the perspective of a leading brake manufacturer. The paper deals with the phenomena of brake vibration and/or noise, the experimental and theoretical methods for studying such phenomena, and the actions that are identified to be necessary to definitely solve the addressed problem. Key topics are the modelling of friction, the modelling of the dynamics of the brake as a non-linear system subjected to deterministic or random (parametric) excitation, the proper modelling of the contact between the disc and the pad, and the experimental validation of the mathematical models.

The paper presents a procedure for the integrated design (tuning) of tyres and suspensions of racing cars. A complete model of a racing car has been developed and implemented. The model is suitable to simulate the vehicle behaviour in extreme driving conditions. A number of ground tests have been performed to validate the vehicle model, with fully satisfactory results. Many different driving situations (steady state, J-turn, lane-change, power-on/off while steering, braking on a bend, passing over a kerb while steering) have been considered. By means of a Multi-criteria approach many performance indexes have been optimised by changing the parameters related both to the vehicle suspension system and to the tyre characteristics. A global-approximation model has been built (the original physical model has been substituted by another purely numerical model), allowing fast optimisations. A number of preferred solutions have been selected from the optimal set. Professional drivers tested the cars fitted with optimal suspension/tyre settings. The improvements predicted by computations were substantially confirmed. The adopted procedure has proved to be reliable and effective both for obtaining the highest performances and for reducing the number of ground tests.

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