Frictional stability and wear resistance are key performance requirements for heavy truck brake linings. Lining-counterface friction affects the rate of vehicle deceleration, but wear also affects stopping characteristics because uneven or high wear can alter the contact geometry of the lining, change the pattern of frictional heat generation, and degrade the response of the braking system. Inertia dynamometer wear tests are commonly conducted in the linings industry, but are expensive and time consuming. It is therefore of interest to seek more convenient, lower-cost test methods that still enable wear rates of various linings to be effectively differentiated. The purposes of the current study were to determine whether the wear of brake lining materials can be measured in shorter-term laboratory tests, and if so, to determine to what extent the relative ranking of several lining materials' wear resistance depends on the method of testing. To investigate these issues, three commercial truck brake lining materials were worn against gray cast iron using three different laboratory-scale wear testing machines. Assessments of wear by gravimetric methods and dimensional changes using the same test apparatus were compared. The three linings ranked in similar order in all three kinds of wear tests, but the relative differences between the wear of one lining and another differed among the test methods. Results are discussed in terms of what test conditions are required to simulate brake lining wear in trucks, and how in situ lining material aging and transfer film formation can affect the wear of brake lining materials. Differences in the entrapment of third-bodies entering the contact had an important influence on the wear results and an additional set of block-on-ring experiments was conducted to demonstrate that effect. Removing wear debris with a wiper pad altered the relative wear ranking of the three materials.

The thesis desribes handling specifications heavy with brake drums. Shows the improper movements of workers who manipulate the loads, which are frequent a source of accident. Shows the and describes possible ways of construction solutions handling truck. In conclusion the work is in progress one solution including drawings and check calculation.

No description available.

Yes / Braking-induced forced vibration, known as brake judder in road vehicles, causes dissatisfaction to drivers and passengers and also damage and possible early failure in components and systems. In this paper, the transmission of judder vibration from the point of generation (the brake friction pair) through the vehicle structure to the driver is investigated for the particular case of a heavy commercial vehicle. The investigation uses a computer simulation multi-body dynamic model based on the automatic dynamic analysis of mechanical systems software to identify any characteristics of the vehicle suspension design that might influence the vibration transmission from the wheel to the driver. The model uses a simplified rigid chassis and cab to lump the chassis parameters, so that the investigation can focus on the front axle/suspension design, which is a beam axle leaf spring arrangement, and the rear axle/suspension assembly, which is a tandem axle bogie design. Results from the modelling indicate that brake judder vibration is transmitted to the chassis of the vehicle through a leaf spring `wind-up¿ mode and a `walking¿ mode associated with the rear tandem axle. Of particular interest is the longitudinal vibration transmitted through the chassis, since this creates a direct vibration transmission path to the cab and driver. The simulation results were compared with the previously published experimental work on the same design of commercial vehicle, and agreement between the predicted and the measured vibration characteristics and frequencies was found. It is concluded that the rear suspension design parameters could affect the transmission of brake judder vibration to the cab and driver and that a tandem rear axle offers some design opportunity to control the transmission of brake judder vibrations from the wheel to the cab and driver. Given that brake judder has so far defied all attempts to eliminate completely from vehicle brake systems, this is potentially an important opportunity.

In the fall of 2004, the High Speed Autonomous Vehicle Team, a group of 16 students took on the goal of converting a vehicle to drive-by-wire status. The main goal of this project was to convert a Cadillac SRX donated by General Motors, to fully by-wire control. This thesis presents the HSAVT brake-by-wire and the steer-by-wire solution. In addition, the results of a literary search on drive-by-wire systems are presented. The results of the project proved that the team came up with a solid, effective drive-by-wire vehicle and that the project met all of the primary goals of the project. / Master of Science

The goal of this experiment was to determine what if any effect two different types of warnings have the brake reaction time of distracted commercial motor vehicle operators. The warning conditions were: No Warning, Auditory Tire Skid Warning, and One Second Brake Pulse Warning. Each participant was distracted via a distracter task during the experiment. As the participants were distracted, an obstacle was launched out into their forward path. Each participant received his/her appropriate warning, according to what condition they were placed, when the obstacle entered their headway. It was determined that the Auditory Tire Skid Warning aided in decreasing the movement times, while the One Second Brake Pulse Warning aided in decreasing the number of collisions with the barrels and speed at contact with the barrels. / Master of Science

yes / This paper presents a two-way thermally-coupled FEM-CFD co-simulation method for ventilated brake disc rotor heat transfer analysis. Using a third party coupling interface for data mapping and exchange, the FEM and CFD models run simultaneously under a standard heavy duty braking test condition. By comparison with conventional one-way coupling methods and experimental results, the performance of the co-simulation system has been investigated in terms of prediction of the heat transfer coefficient (HTC) and disc temperatures as well as computing time used. The results illustrate that this co-simulation method has good capacity in providing cooling effect and temperature predictions. It also shows that the data exchange between the FEM and CFD codes at every time increment is highly accurate and efficient throughout 10 brake applications. It can be seen that the cosimulation method is more time efficient, convenient and robust compared to previous oneway coupling methods. To utilize the potential of this method, future works are proposed.

No / Given that most of the working life of a brake pad life is spent in the bedded condition, it is important to examine the conditions of a fully bedded contact interface. An experimental and a numerical method are combined. Contact pressure and its effects (heat generation/partition and temperature rise) for the drag braking process with and without bedding are compared. The real contact area is also measured and found to be increased for the bedded interface. This results to the contact pressure being ¿more¿ evenly distributed than before. Spreading the contact pressure also results in increasing the total heat transfer between the disc and pad since now more heat can be transferred from the pad (where it is generated) to the disc. It is concluded that in order to have a reliable simulation it is recommended that the bedding-in effects are introduced in the simulations. / IMechE, RAE Travel Grant

No / There are several types of disc brake instabilities associated with the brake systems; however, they are usually classified into two main categories depending on the frequency range: brake groan 0–300 Hz and brake squeal 1– 16 kHz. The groan is associated with the stick-slip motion while the squeal is associated with the modal coupling. This paper presents a detailed analysis of low frequency noise (0–300 Hz) in a commercial vehicle trailer disc brake as a result of stick-slip vibration. A range of experimental techniques are used to understand the characteristic behaviour of the caliper and the brake pads during braking events on a laboratory test rig. The analysed brake system comprised a full disc brake assembly and the trailer suspension system with a beam axle. Laser-based optical displacement sensors were used to investigate the deformation of the caliper body and the brake pads during a braking application. The contact pressure distribution at the disc/pad interfaces were also measured to gain more insight into the contact profile of the pad surfaces. Results revealed that the stick-slip phenomenon, in this study, was a result of the combination of the deformation of the caliper and the friction material formulation of the brake pads. In addition, it was observed through the testing of two different sets of pads that a low compression modulus would help to reduce the stick-slip phenomenon.

Pastilhas de freio para sistemas de freios automotivos correspondem a um dos materiais compósitos mais complexos já que eles contêm muitos componentes, cada qual com uma grande variedade de propriedades físicas e químicas. Esta natureza multi-fase é necessária para satisfazer a grande variedade de demandas relativas à performance. As condições de processamento também possuem grande influência nas propriedades deste complexo compósito. As pastilhas de freio usadas neste trabalho foram sem amianto do tipo semi-metálica contendo muitos elementos, incluindo resina fenólica, fibra de reforço, lubrificantes sólidos, abrasivos e cargas. Este trabalho tem como objetivo principal esclarecer a influência entre as variáveis de processo e de composição nas propriedades de compressibilidade a frio, densidade, dureza, flexão e coeficiente de atrito. Para isso foram utilizados planejamentos de experimentos fracionados e completos. O planejamento de experimentos fracionado, 25-1, indicou que a quantidade de resina fenólica e a temperatura do molde são os fatores mais significativos para a compressibilidade. O planejamento de experimentos completo, 24, mostrou mais uma vez, que a quantidade de resina e a temperatura do molde, bem como as suas interações, são fatores significativos na determinação da compressibilidade. O terceiro planejamento de experimentos, 2³, concentrou-se nas propriedades da resina, já que a mesma mostrou-se muito influente na determinação das propriedades dos materiais de atrito. Os resultados mostraram que é possível controlar as propriedades tribológicas e a compressibilidade das pastilhas de freio dentro de certa escala de valores. Assim, este trabalho mostra que é possível aplicar técnicas estatísticas para racionalizar o projeto de materiais de atrito. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-14T18:07:18Z No. of bitstreams: 1 Dissertacao Ademir R Menetrier.pdf: 3142797 bytes, checksum: 973f28293a5f77372f68c6146e790438 (MD5) / Made available in DSpace on 2014-05-14T18:07:18Z (GMT). No. of bitstreams: 1 Dissertacao Ademir R Menetrier.pdf: 3142797 bytes, checksum: 973f28293a5f77372f68c6146e790438 (MD5) / Brake pads for automotive brake systems represent one of the most complex composite materials since they contain many components with widely varying physical and chemical properties. This multiphase nature is necessary to satisfy a wide variety of performance related demands. Processing conditions also have a major influence on the properties of these complex composites. Brake pads used in these studies were semi-metallic non-asbestos friction materials containing many different ingredients, including phenolic resin, reinforcing fibers, solid lubricants, abrasives and fillers. In this work, the influence of composition and process parameters on the compressibility, density, hardness, flexure strength and coefficient of friction were investigated. The designs of experiments selected for this study were fractional and full varieties. In the initial fractional design of experiments, we found both the quantity of resin and the mold temperature to be dominant influences on the compressibility. A full design of experiments again indicated that the quantity of resin and mold temperature, as well as their interaction, are the dominant players in determining the compressibility. A third design of experiments concentrated on the resin properties since this factor was the most influential in determining the properties of friction materials. The results show that it is possible to control both the tribological properties and the compressibility of the pads within a rather large range of values. Thus, the work shows that it is possible to use statistical methods to rationalize brake pad design.