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An Application of Shape Optimization to Brake Squeal Phenomena

SAE International Journal of Passenger Cars - Mechanical Systems

Gifu University-Kohei Furuya
Toyota Motor Corp.-Kohei Shintani, Satoshi Ito
  • Journal Article
  • 2015-01-2658
Published 2015-09-27 by SAE International in United States
The present paper describes an application of non-parametric shape optimization to disc brake squeal phenomena. A main problem is defined as complex eigenvalue problem in which the real part of the complex eigenvalue causing the brake squeal is chosen as an objective cost function. The Fre´chet derivative of the objective cost function with respect to the domain variation, named as the shape derivative of the objective cost function, is evaluated using the solution of the main problem and the adjoint problem. A selection criterion of the adoptive mode number in component mode synthesis (CMS), which is used in the main problem, is presented in order to reduce the computational error in complex eigenvalue pairs. A scheme to solve the shape optimization problem is presented using an iterative algorithm based on the H1 gradient method for reshaping. For an application of the optimization method, a numerical example of a practical disc brake model is presented. The numerical result illustrates that the real part of the target complex eigenvalue monotonously decreases until it reach zero.
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Effective Simulation of the Boundary Layer of an Entire Brake Pad

Tu Braunschweig-Georg Ostermeyer, Joshua Merlis
Published 2015-09-27 by SAE International in United States
The dynamic friction behavior of automotive brakes is generated by the boundary layer dynamics between pad and disk [OST01]. A key component of the Friction Interface is the influence of mesoscopic surface contact structures known as patches, upon which the friction power is concentrated, and whose sizes vary with time. Through this dynamic process, time and load history-dependent effects come about, which cause, for example, the brake moment behavior commonly observed in an AK-Master test.In recent years, several simulation tools have been developed in order to predict the complex friction behavior caused by the patch dynamics in the friction boundary layer. Such simulations are often based on a two or three-dimensional spatial grid, where the explicit physical phenomena at all locations in the boundary layer are modeled by time-consuming calculations of local material dependent balance equations.A new abstract Cellular Automata simulation tool is introduced, which reduces the necessary computation to the patches in the friction boundary layer. Rather than making use of a spatial grid, each patch is considered a single cell, whose size can…
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Brake Squeal and Wheel Dust vs. Disc Wear: No-Copper, Low-Copper and High-Copper NAOs

SAE International Journal of Materials and Manufacturing

Compact International Co., Ltd.-Meechai Sriwiboon, Nipon Tiempan, Kritsana Kaewlob
SKR Consulting LLC-Seong Rhee
  • Journal Article
  • 2015-01-2660
Published 2015-09-27 by SAE International in United States
In a previous investigation, brake squeal was found to be related to disc wear, but not to pad wear or in-stop average coefficient of friction as tested according to the SAE J2522 performance procedure, using Low-Copper NAOs. To further validate the disc wear - squeal correlation, a variety of formulations of No-Copper, Low-Copper and High-Copper NAO disc pads were made and tested to investigate friction, pad wear, disc wear, brake squeal and wheel dust formation. It is found that disc weight loss measured at the end of the burnish cycle of the SAE J2522 (AK Master) is closely related to dynamometer/vehicle brake squeal and vehicle wheel dust formation, and that there is a critical disc wear rate of approximately 1.0 grams for the current brake system, below which brake squeal and wheel dust are minimal. It is also found that there is no correlation between brake squeal and in-stop average friction coefficient, in-stop maximum friction coefficient or in-stop friction coefficient variations during the burnish cycle of SAE J2522 (AK Master).
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Control of Novel Integrated-Electro-Hydraulic Brake System for Automotive

Tongji University-Songyun Xu, Zhuoping Yu, Lu Xiong
Published 2015-09-27 by SAE International in United States
With the electrification and intelligentialization of vehicle, requirements on more intelligent and integrated brake system are put forward. A novel integrated-electro-hydraulic brake system (I-EHB) for automotive is presented to fulfill these requirements. I-EHB is consisted of active power source (APS), pedal feel emulator (PFE), electro control unit (ECU) and hydraulic control unit (HCU). The system characteristics of I-EHB are tested through test rig. According to characteristics experiments, friction and non-linear phenomena in hydraulic pressure control are found. In order to overcome these phenomena in control of I-EHB, chatter-compensation is adopted based on experiment analysis. Algorithm are tested and optimized through test rig. As a result, through chatter-compensation the hydraulic pressure is controlled accurately and chatter-compensation is optimized for different working conditions.
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Study on the Braking Torque Allocation of the ABS Based on the Frequency of the Electro-Hydraulic Brake

Shanghai Volkswagen-Yilin Ren
Tongji University-Guirong Zhuo, Fei Yu
Published 2015-09-27 by SAE International in United States
Study on the braking torque allocation of the ABS (Anti-lock Brake System) of the electro-hydraulic brake system in the distributed drive electric vehicles, using a hierarchical control structure, of which the lower controller takes a braking torque allocation strategy based on frequency, so as to achieve a good braking effect. The lower controller uses the strategies which are based on the filter principle or the weighted least squares algorithm. To the former, Butterworth filter is selected to execute the braking torque allocation. Then the ABS braking torque allocation strategy based on Butterworth filter and the weighted least squares are designed and analyzed respectively, finally their braking effects are simulated and contrasted in Simulink and AMESim.
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Effects of ‘Black Steel’ and its Contribution to Premature Brake Pad Replacement and Brake Pad Failure

NUCAP Industries Inc.-Scott Lambert
Published 2015-09-27 by SAE International in United States
The Global Brake Safety Council sees an increase in disc brake pads that are prematurely replaced before the end of the friction lining life cycle, due to: 1Rust related issues such as separation of friction lining from the disc brake shoe2Fluctuation in critical dimensions.A leading cause for both issues is the use of mill scale steel, or ‘black steel’ (non-pickled and oiled). In the North American aftermarket, as there are little or no steel specifications for disc brake shoes, black steel is increasingly used.GBSC conducted research of discarded disc brake pads from job-shops and engaged in discussions with metallurgists, major pad manufacturers and OE brake foundation engineers to identify root causes of premature pad replacement and the effects of black steel used for disc brake shoe manufacturing.Mill scale is embedded in and around the bond line of the friction lining and the disc brake shoe, causing a weaker bond, susceptible to rust jacking. These oxides are also painted over after the pad is assembled, compromising paint adhesion.Manufacturers using black steel shot blast the disc brake…
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Identification of Organic Compounds Released from Low-Metallic Automotive Model Brake Pad and its Non-Airborne Wear Particles

SAE International Journal of Materials and Manufacturing

ENET Centre, VSB-TU-Jana Kuchařová
Nanotechnology Centre, VSB-TU-Daniela Plachá, Pavlina Peikertova, Jana Kukutschova, Kristina Čabanová, Jiří Karas
  • Journal Article
  • 2015-01-2662
Published 2015-09-27 by SAE International in United States
The brake wear contribution to the environmental pollution has been extensively discussed, with major focus on asbestos and heavy metals released to the environment. Only limited attention was paid to released organic compounds generated during friction processes, although the organic and carbonaceous components are not the minor part in brake lining formulations.Friction processes in brakes are associated with relatively high temperatures and high pressures on the friction surfaces which relates to the thermal decomposition of the organic components in friction materials and to brake lining thermal fade. Thus, this study focuses on the identification of organic compounds released from a model low metallic brake material. Several methods were used for the analysis: GC/MS screening of brake pad samples, brake wear debris and carbonaceous raw materials used in formulations of model pads; GC/MS screening of brake pad samples pyrolyzed at 300, 750, and 1000°C, respectively, and FTIR analysis of brake pads and their wear debris.Higher quantity of organic compounds was identified in extract of the milled brake pad composite compared to the wear debris. More than…
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The Research on Electrical Parking Brake System based on Frictional Model

Wuhan University of Technology-Meixia Ji, Xuexun Guo, Zhenfu Chen, Bin Wang
Published 2015-09-27 by SAE International in United States
The control forms of the vehicle have transformed from hydraulic or mechanical control to electrical control owing to the increasing demand of automotive safety and soaring development of electronic technology. Compared with the traditional mechanical parking brake system, the electrical control of brake named Electrical Parking Brake (EPB) System presents a variety of advantages. What's more, it shares common actuators and realizes the communication between electrical control systems to advance the vehicle industry to intellectualization.With such superiority, the EPB System has aroused much interest. But the difficulty in building the simulation model lies in the description of friction in screw-nut system of which the nonlinear component causes the hysteresis. However, almost all models found in the literature before are the static friction model with the limit of description of dynamic features like pre-sliding frictional features and parameters variation.A method to describe the friction feature is proposed based on the LuGre dynamic friction model in this paper. In contrast to the static friction model, the paper demonstrates the LuGre model's advantages over the Stribeck model. In…
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Configuration of Brake Components

SAE International Journal of Commercial Vehicles

Continental Corp.-Ulrich Ungethuem, Dirk Simon
  • Journal Article
  • 2015-01-2668
Published 2015-09-27 by SAE International in United States
The hydraulic brake products like brake calipers, master cylinders and boosters are the foundation of today complex vehicle brake systems. The state of the art application leads very often to an individual design, due to the fulfillment of customer requirements within the available installation space. Also the enormous pressure on cost and time require optimized design processes. Therefore Continental developed the product configuration software CoBra. Within this software tool, the engineering is able to react very fast on demands. Starting with the brake sizing parameters and the customer interface definition, CoBra supports the design engineer to select the necessary components and positioning them accordingly, considering the actual design standards. The data based configuration software collects all necessary design parameters and provides an export to parametric CAD start up models. Therefore a high level of data quality can be achieved which allows to couple further design and simulation modules. Today all caliper types and the master cylinders are part of the actual software version. In summary we can state that CoBra, as the basis for the…
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Brake Pedal Feel Control Model

University of Belgrade Fac. of Mech. Eng-Dragan Aleksendric, Velimir Cirovic, Dusan Smiljanic
Published 2015-09-27 by SAE International in United States
Customer perception of brake pedal feel quality, depends on both the customer's subjective judgment of quality and the actual build quality of the brake system. The brake performance stability represents an important aspect of a vehicle performance and its quality of use. This stability is needed especially in brake by wire system and braking system with regenerative braking. In order to provide stable braked pedal feel i.e. consistent the brake performance against the brake pedal travel, the model of the brake performance versus the brake pedal travel needs to be established. In this paper new hybrid neuro-genetic optimization model was developed for dynamic control and optimization of the disc brake performance during a braking cycle versus the brake pedal travel. Based on such model, the brake performance optimization of the passenger car has been provided against the brake pedal travel. It enables different setting of the brake pedal feel for wanted braking system responses which is useful for brake by wire systems.
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