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Brake Colloquium & Exhibition - 37th Annual
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Characteristics of a Brake Disc’s Nonuniform Thermomechanical Responses to an Emergency Braking

Winhere Auto Parts Mfg Co.-Qianjin Yang, Fulin Gai, Liqiang Song, Hui Yu, Baozhi Zhang
Published 2019-09-15 by SAE International in United States
Brake discs in service are subjected to the combined thermal and mechanical loadings. Due to the complex interactions of different parts in operating brake systems and various thermal and mechanical boundary conditions, the thermomechanical responses of brake discs are highly nonuniformly distributed across the brake discs. In this paper, a detailed finite element analysis model was developed to understand the thermomechanical responses of a solid brake disc to an emergency braking. The temperature and the stress in the brake disc were then characterized thoroughly in the radial, circumferential and thickness direction of the disc, and it was found that they were all nonuniformly distributed in the three directions. Furthermore, the stress responses of the disc due to the combined thermal and mechanical loadings were separated into thermal stress and mechanical stress, and their particular characteristics to the individual thermal or mechanical loading were identified. That is: the amplitude of the total stress in the disc was predominately determined by the thermal loading; however the high cycle fluctuations were mainly due to the mechanical loading. All…
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The Influence of Differential Pad Wear on Low-Frequency and High-Frequency Brake Squeal

SKR Consulting Inc.-Seong K. Rhee
Technische Universitat Braunschweig-Johannes Otto, Georg-Peter Ostermeyer
Published 2019-09-15 by SAE International in United States
The NVH behavior of disc brakes in particular, is in the focus of research since a long time. Measurements at a chassis dynamometer show that brake pad wear has a significant influence on the occurrence of low- and high-frequency squealing [1]. It is suspected that high-frequency squealing is more likely to occur when the wear difference between the inner and outer brake pad is small. In the other case, if the differential wear rate between the inner and outer pads becomes higher, the prevalence of low-frequency squealing increases.In order to examine this hypothesis, this work focuses on a simplified model of a commercial brake system [2]. In a first step, the inner pad’s wear is iteratively increased, while the wear on the outer pad remains unaffected. In a second step, the coefficient of friction at the worn pad is iteratively increased to investigate the influence on the low and high-frequency squealing. With the aid of the Complex Eigenvalue Analysis (CEA), the real part of the eigenvalue is used as a quantification measure in order to…
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The Analysis of Brake Squeal Noise Related to the Friction Properties of Brake Friction Materials

Hyundai Motor Company-Sang-mok Lee, Jung Hoon Woo, Dong Won Kim
Hyundai Motor Company & KIA Motors Corporation-Younggu Cho
Published 2019-09-15 by SAE International in United States
The friction properties related to squeal noise was analyzed with the development histories and simplified computational method. Firstly, the development histories were investigated especially focusing on the case which the friction materials were modified to improve squeal noise occurrence. Based on the histories, the friction properties of selected friction materials were newly measured using dynamometer. The average friction coefficient levels, torque oscillations, the increment of friction coefficient during full-stop, and etc. were compared with the squeal noise occurrence, and the results showed that increase of friction properties cause production of squeal noise. The result suggested that the size of friction energy was important factors related to triggering the squeal noise. Also, the contact conditions between rotor disc and friction materials were significant factors deciding the noise occurrence. We performed simplified computational analysis using MATLAB program to prove the effect of friction energy on the noise occurrence. The friction surfaces were roughly designed and the distribution of contact plateaus was controlled to simulate different contact conditions. The different contact conditions were designed and performed sliding at…
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Study on Application Methods to Mitigate Galvanic Corrosion between Wheel Bearing and Aluminum Knuckle

Iljin Global-Sewoong Kim, Seonho Lee, Hyounsoo Park
Published 2019-09-15 by SAE International in United States
The substitution of aluminum for steel is an effective weight reduction solution where the application permits it; aluminum knuckles have been widely used for this reason. However, when an aluminum knuckle is assembled with the steel outer-ring of a wheel bearing without any means for galvanic corrosion prevention, the aluminum knuckle may severely corrode. Galvanic corrosion products can make it difficult to remove a wheel bearing from the aluminum knuckle during vehicle maintenance. Prevention of this problem is the focus of this paper. In this study, several concepts were examined to prevent or mitigate galvanic corrosion between a wheel bearing and its mating aluminum knuckle. One set of concepts involves using surface treated metal sleeves (using ferritic nitro-carburizing or a special coating). The sleeves were then inserted onto the outer-ring diameters of the wheel bearings prior to assembly into the steering knuckle. Another set of concepts that were investigated involves the application of thin coatings having high anti-corrosion properties. The coatings were applied directly to the bearing outer-ring knuckle piloting surfaces and bearing knuckle mounting…
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Brake Pedal Feeling Comfort Analysis for Trucks with Pneumatic Brake System

Ford Motor Company-Wesley Bolognesi Prado, Silvia Faria Iombriller, Marco Andre Silva, Lázaro Renato Oliveira
Published 2019-09-15 by SAE International in United States
The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand.Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel.On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior. However, for pneumatic brake systems, the pedal feel theoretical study is not usual, where is normally used for these developments, exclusively the subjective evaluation which become necessary to have more specialists to define the brake pedal behavior.Throughout this article will be revised the characteristics concepts…
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Real Driving Emissions Measurement of Brake Dust Particles

Technische Universitat Ilmenau-David Hesse, Klaus Augsburg
Published 2019-09-15 by SAE International in United States
The measurement of brake dust particles is a complex challenge owing to its open system configuration; indeed, the emitted particles are directly spread into the environment. Measurements on the inertia brake dyno feature controllable and reproducible environmental and operational parameters. Although Real Driving Emission (RDE) measurements enable the detection of brake dust particles emitted in real driving conditions (i.e. traffic condition, driving style, air humidity, vehicle components’ wear and ageing, etc.), they are complex and not reproducible due to external, continuously changing parameters (e.g., flow conditions, changing traffic conditions, particulate matter from other sources). The motivation lies in developing a real driving emission sampling system for brake particle emissions, which meets the quality requirements of the measurements, as well as the prevention of particle losses and contamination, thereby supplementing and reviewing laboratory-based procedures. On the basis of knowledge from the computational fluid dynamics and experimental investigations, an advantageous concept of a sampling system for mobile application is presented. The chosen methodological approach shows that the transport efficiency and the uniformity of the number concentration depend…
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Stability of Wheel Tractors during Braking

Kharkiv Technical University of Agricult-Zadorozhnia Viktoriia
Kharkov National Auto and Highway University-Mikhail Podrigalo, Mykhailo Kholodov, Dmytro Klets, Yevhen Dubinin, Borys Savchenkov, Alexander Koryak, Oleksandr Polianskyi
Published 2019-09-15 by SAE International in United States
The dynamic distribution of normal reactions between the axles of the wheeled tractor has a significant impact on the stability against skidding and the wheeled tractor braking effectiveness. At the same time, the clarification of the normal reactions distribution between the axles allows to choose more rational braking forces distribution between the axles.It is shown that the best way to ensure the highest braking efficiency is the braking mode when the rear wheels of the tractor are at the blocking limit. An assessment of the expediency of installing brake mechanisms on only one axle of the tractor was made.The increase of braking efficiency of wheeled tractors with all brake wheels provided that they ensure directional stability is considered. The laws of braking forces distribution between the axles of wheel tractors for different sequence of wheels locking are determined.Using the method of partial accelerations an improved method for estimating the effect of a brake system on the stability of wheeled tractor is proposed. The criterion in the form of angular acceleration in the road plane ώz,…
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Influence of Amount of Phenolic Resin on the Tribological Performance of Environment-Friendly Friction Materials

Indian Institute of Technology Delhi-Navnath Kalel, Jayashree Bijwe, Ashish Darpe
Published 2019-09-15 by SAE International in United States
The binder in friction materials (FMs) plays a very crucial role which binds all the ingredients firmly so that they can function the way they were supposed to do. The type and amount of binder, both are very critical for manipulating the desired performance properties, which mainly include friction and its sensitivity towards operating parameters, wear resistance, counter-face friendliness, noise, vibration etc. Although a lot is reported on the influence of types of resins on tribo-performance of FMs, hardly any paper pertains to paint this on a bigger canvas with more detailed understanding of the amount of resin in FMs on the performance properties.The present study addresses these aspects by developing brake-pads with identical composition but varying in amount (wt. %) of straight phenolic resins (6, 8, 10 and 12) by compensating the difference with barite, a space filler. The ingredients did not contain asbestos, Copper, Zinc, etc. and hence were environment friendly. Tribological performance of the composites was evaluated on a full-scale inertia brake dynamometer following JASO C406 test schedule. With increase in the…
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Analysis of the Tractor-Trailer Dynamics during Braking

Kharkov National Auto and Highway University-Mikhail Podrigalo, Dmytro Klets, Mykhailo Kholodov, Valeriy Klimenko, Anton Kholodov
Zhytomyr State Technological University-Volodymyr Rudzinskyi
Published 2019-09-15 by SAE International in United States
The intensive development of tractor-building industry in the world has led to the widespread use of wheeled tractors and tractor trains in transportations on public highways. This requires an increase of engine capacity and speed of tractor trains, as well as strict demands for their braking systems.The formation of the necessary braking properties of wheeled tractors and tractor trains on their basis should be carried out at the design phase, taking into account a wide range of aggregated machines and tools.Blocking the wheels of the trailer with different sequence of their blocking and blocking the wheels of the tractor has significant impact on the total braking force, deceleration and stability of the tractor train. It is advisable to take this into account when modeling the braking process of a tractor train.The article deals with the braking dynamics of the tractor train and the impact of the dynamic distribution of normal reactions between the axles on the brake properties of the tractor train. The mathematical model of the braking process of the tractor-trailer train (consisting of…
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Divergence of Thickness Loss vs. Weight Loss, Friction and Wear Behavior of Heavy Truck Brake Blocks: Development of a New Test Procedure for the Chase Tester

Ask Automotive Pvt, Ltd.-Aman Rathee, Devendra Kumar Sharma, Shivraj Singh
SKR Consulting LLC-Seong Kwan Rhee
Published 2019-09-15 by SAE International in United States
Heavy truck brake blocks are found to swell (or expand) permanently during testing or usage, especially so at high temperatures, thus leading to longer durability as measured by thickness loss, similar to light vehicle disc pads. This swelling phenomenon occurs continuously in the layer adjacent to the friction surface during testing or usage; not a one time event. The thickness loss estimated from the weight loss is always greater than measured thickness loss. Brake block wear does not increase linearly with increasing normal load, and the load-sensitivity of block wear is very much dependent on the products. A new test procedure has been developed for generating friction-vs.-temperature and wear-vs.-temperature data at a constant temperature employing intermittent braking on the Chase Brake Lining Quality Tester (SAE J661) and friction material wear can be compared on equivalent-work basis.
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