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A safe public transport every citizen’s right, so vehicular safety are ruled by standards and regulations, where bus manufacturing companies must comply with such requirements, ensuring that the body structure will be able to guarantee the physical integrity its occupants, even against events such as vehicle rollover. CONTRAN 629 resolution is the Brazilian standard responsible for defining the minimum safety values, setting out the procedures and test methods to be performed to certify the mechanical strength of a M3 category vehicle. In this context the present paper seeks to develop a methodology that allows to perform a numerical evaluation for the structure of an urban bus, verifying if the proposed frame meets the mechanical requirements established by standards. Thereby, it was performed an experimental test and numerical simulation of a structural module, which represents the frame of an urban bus.

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.

One effect which is present in drum and disc brakes is the temperature. This effect significantly changes the vehicle and semi-trailer combinations performance, mainly in drum brakes that is more susceptible to this factor. High temperatures mean loss of efficiency, higher lining wear, brakes and rolling systems components life reduction and could be caused by many factors, which can be mentioned, overload, error in design and choice of brake system, speeding, over adjustment (dragging) and environment heat exchange. The challenge is to comprehend the relation between different brake configuration and how these configurations affects the temperatures generation on brake system, allowing that this factors can be evaluated during the project design. This paper aims to show a case study for a new brake family to be used in city bus application where the fleets are looking for better, safety, performance and low lining wear reduce the to increase the maintenance time.

It is widely known that a typical brake system works by mitigating vehicle kinetic energy and transforming it into thermal energy, ultimately leading to energy dissipation. The main concerns related to this kind of system are: 1) low frequency vibration energy propagating throughout the vehicle structure when the system begins its unblocking action; and 2) high frequency vibration energy propagation which induces undesirable noise levels. Modal analysis of the system can provide important information about its vibration characteristics. Provided that coupling between the dynamic behavior, the pre-stress caused by the applied load, and friction characteristics will certainly occur, it is required that analyses be performed on the entire assembly. As such, this paper presents evaluation of a brake disc system regarding the brake squeal using finite element method comparing with experimental assessment.