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The present work aims to investigate the influence of wear of the pads and brake disc on the brake squeal behavior with the help of the Finite Element tool. Brake discs basically work by the pressure of the brake pads against a rotating disc. The friction between the pads and the disc causes the latter to decelerate, but it can also cause dynamic instabilities of the system giving rise to noises. Among the main noise in vehicle brake systems, there is the squeal noise, which is usually associated with the coupling of two neighboring natural modes. One possible way to identify unstable modes is by extracting complex eigenvalues from the system. An unstable mode can be identified when, in the result of the extraction of the complex eigenvalues, the real part of the eigenvalue is positive. In the present work, a brake system (disc and positioned pads and their respective materials and friction coefficients) was duly modeled and validated.

This study aims at analyzing the causes of noise in a heavy vehicle brake system (6x2 tractor) and proposing solutions to improve comfort during braking as it is known that, during the activation of the automotive brakes, noise can be generated in different frequency bands that can cause discomfort to the user and the study of how to reduce it is considerably important to bring more comfort in its use. As a working methodology, firstly, comparative analysis of dimension and material were performed between the axle assembly that presented noise and another axle assembly of a vehicle with no noise adopted as reference. This information was used as the basis for the frequency and acceleration virtual analysis that were validated with vehicle instrumentation and data acquisition. In parallel, vehicle tests with different brake friction materials were conducted.

This work consists in a study about regulations for brake system in Brazil, which aims to show the current scenario, as well as the evolution of the resolutions and technologies. Within the last few years Brazil had a considerable evolution in terms of safety requirements for brake systems. In 2009 an important step was taken when Brazilian Traffic National Consil (Conselho Nacional de Trânsito - CONTRAN), the agency responsible for traffic regulations in Brazil, emitted the resolution N° 312, which established the mandatory use of Anti-lock Brake System (ABS). This obligatoriness was introduced gradually, beginning by passengers cars in 2010, when 8% of the automobiles manufactured in that year should have the system installed as standard item. This percentage would increase until reaching 100% of vehicle production in 2014.

With the advent of CONTRAN resolution 641:2016 [1], became mandatory the Stability Control Systems on all articulated vehicles, that will be commercialized in Brazil from 2025. This resolution [1] aim to prevent the principal accident type involving heavy vehicles: The Rollover incidents. It is known that Brazilian heavy trucks market presents several peculiarities on vehicles configurations, in relation of European and American markets. Basically, it can be said that Brazilian articulated cargo vehicles are longer and heavier than American and European cargo vehicles. These characteristics make Brazilian vehicles more susceptible to lateral instabilities. These characteristics raise an important question about what will be the real effectiveness of these electronical stability control systems when it will be applied on these Brazilian cargo vehicles.