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Modeling and Identification of an Electric Vehicle Braking System: Thermal and Tribology Phenomena Assessment

Siemens Industry Software NV-Thomas D’hondt, Bart Forrier, Mathieu Sarrazin
Università degli Studi di Firenze-Tommaso Favilli, Luca Pugi, Lorenzo Berzi, Riccardo Viviani, Marco Pierini
  • Technical Paper
  • 2020-01-1094
To be published on 2020-04-14 by SAE International in United States
A rapidly shifting market and increasingly stringent environmental regulations require the automotive OEMs to produce more efficient and low-emission electric vehicles. Regenerative braking has proven to be a major contributor to both objectives, enabling the charging of the batteries during braking on one side, and a reduction of the load and wear of the brake pads on the other side. The optimal sizing of such systems requires the availability of good simulation models to improve their performance and reliability at all stages of the vehicle design. This enables the designer to study both the integration of the braking system with the full vehicle equipment and the interactions between electrical and mechanical braking strategies. The present paper presents a generic simulation framework for the thermal and wear behavior of a mechanical braking system, based on a lumped parameter approach. The thermal behavior of the system is coupled back to the friction coefficient between the pad and the disc to assess its effect on braking performance. Additionally, the effect of wear and temperature on the generation of…
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Vehicle validation for pressure estimation algorithms of decoupled EHB based on actuator characteristics and vehicle dynamics

DIAS Automotive Electronics Co.,.Ltd.-Songyun Xu
Tongji University-Wei Han, Lu Xiong, Zhuoping Yu
  • Technical Paper
  • 2020-01-0210
To be published on 2020-04-14 by SAE International in United States
In the automotive field, electro-hydraulic brake systems (EHB) has been developed to take place of the vacuum booster, having the advantage of faster pressure built-up and continuously pressure regulation. Most of the pressure control solutions are based on standard pressure-based feedback control, requiring a pressure signal. Although the pressure sensor can produce the pressure feedback signal, it will increase cost and enlarge installation space. The rotation angle of electric motor is available by the built-in sensor, so the pressure can be estimated by using the rotation angle. The pressure control is influenced intensely by the typical nonlinearities (i.e. friction, pressure-position relationship) and uncertainties (i.e. brake pads wear, temperature effect). To address these issues, this work improves an interconnected pressure estimation algorithm based on actuator characteristics [W. Han, L. Xiong, and Z. Yu, “Pressure estimation algorithms in decoupled electro-hydraulic brake system considering the friction and pressure-position relationship,” SAE Technical Paper 2019-01-0438, 2019] by introducing the vehicle dynamics and validates it via vehicle tests. The mathematical model of the motor-type EHB is built. The Gauss exponential model…
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Model-based brake disc temperature prediction on high speed testing mode and circuit

AVL LIST GmbH-Mario Oswald, Stefan Kellner
Hyundai & Kia Corp.-PilYoung Jeong
  • Technical Paper
  • 2020-01-0214
To be published on 2020-04-14 by SAE International in United States
Brake force of vehicle generated by the kinetic energy of vehicle is transformed into heat energy by using the brake pad materials and friction of disc and heated temperature reflect the disc. At the same time, it is transmitted into the air or around components. Heated temperature cause the problem of fade performance which is happened degradation of friction coefficient between disc and pad materials and cause dramatic pad wear. Therefore, to develop sufficiently obtained thermal capacity of disc dimension is quite important process in initial concept development. In order to approach well concept of development in brake, Thermal capacity of disc should be predicted reliably and precisely. This paper built the brake thermal simulation modeling which is possible to predict the disc capacity based on parameterization of front and rear disc development. And it predicted analytically by using brake thermal simulation modeling for European brake mode generally called by AMS mode which affect big influentially for brake disc capacity design as well as consider the characteristics of high performance vehicle on the circuit. Study…
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Contiguous Aircraft/System Development Process Example

S-18 Aircraft and Sys Dev and Safety Assessment Committee
  • Aerospace Standard
  • AIR6110
  • Current
Published 2020-02-05 by SAE International in United States
This AIR provides a detailed example of the aircraft and systems development for a function of a hypothetical S18 aircraft. In order to present a clear picture, an aircraft function was broken down into a single system. A function was chosen which had sufficient complexity to allow use of all the methodologies, yet was simple enough to present a clear picture of the flow through the process. This function/system was analyzed using the methods and tools described in ARP4754A/ED-79A. The aircraft level function is “Decelerate Aircraft On Ground” and the system is the braking system. The interaction of the braking system functions with the aircraft are identified with the relative importance based on implied aircraft interactions and system availabilities at the aircraft level. This example does not include validation and verification of the aircraft level hazards and interactions with the braking system. However, the principles used at the braking system level can be applied at the higher aircraft level. The methodologies applied here are an example of one way to utilize the principles defined in…
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Independent Aftermarket (IAM) and the Three Dimensions of Friction Material Evaluation

LINK South America-Pedro Oliveira, Henrique Rodrigues, Eduardo Ferro
  • Technical Paper
  • 2019-36-0006
Published 2020-01-13 by SAE International in United States
It is well known the difference between development levels and engineering investment applied to passenger car brake pads when compared to Original Equipment Manufacturer (OEM) and items sold in the Independent Aftermarket (IAM). Based on these differences, the objective of this paper is to propose a simple evaluation for the IAM that can provide at least some level of the understanding of frictional material behavior. Based on a tripod of variables, or three Dimensions Development, described in this work as Performance, Comfort (NVH) and Durability; and using internationally and established testing procedures to measure these dimensions in order to meet the IAM demands for the cost-benefit engineering investment. An important part of the proposed tool is to position friction material against competition for market known issues, and, more importantly, to ensure end product safety and reliability.
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Regressions of brake pads compressibility from experimental data

TMD Friction do Brasil S.A.-André Garcia Lima Suetti
  • Technical Paper
  • 2019-36-0014
Published 2020-01-13 by SAE International in United States
One of the critical characteristics in a brake pad is its deformation when subjected to compressive loads. This deformation is called compressibility, which can be obtained quantitatively through compression cycles performed by a specific test bench. However, such testing is costly and long enough not to meet the demand of manufacturers of friction materials.To overcome this difficulty, this work presents regressions for the estimation of compressibility through the natural frequencies of the pads, since they can be obtained quickly and at low cost through a simple modal analysis. The theoretical basis for the correlation between compressibility and natural frequencies includes the theory of elasticity - which defines an inverse relationship between strain and stiffness - and the theory of vibrations, which defines the natural frequencies of a mechanical system as a function of its mass matrices and stiffness. Since the dependent variable (compressibility) and explanatory variable (natural frequency) are linked to stiffness, it is theoretically plausible to direct estimative.As additional explanatory variables, in addition to the experimental data of natural frequencies, the work uses the…
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Influence of Pads and Brake Disc wear on Brake Squeal Noise

Universidade Federal de Minas Gerais / FCA - Fiat Chrysler A-Marco Túlio Batista dos Anjos, Juan Carlos Horta Gutiérrez, Cláudio Junior Ferreto, Felipe Dornellas Silva, Lázaro Valentin Donadon
  • Technical Paper
  • 2019-36-0005
Published 2020-01-13 by SAE International in United States
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. The validation was done by means of a correlation between the frequency of the noises found…
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Fabrication and Wear Characteristics Basalt Fiber Reinforced Polypropylene Matrix Composites

Dhanalakshmi Srinivasan Institute of Technology-Krishnaraj M, Thirugnana Sambandha T, Arun R
Trichy Engineering College-Vaitheeswaran T
  • Technical Paper
  • 2019-28-2570
Published 2019-11-21 by SAE International in United States
Generally brake pads are manufacturing by use of asbestos materials, that materials are chemically harmful and toxic nature to affect the human health. The present investigation is to fabricates polypropylene composites with mixing constant volume [5 vol.%] of alumina nano particles and different volume percentages [0%, 5%, 10% & 15%] of basalt Fiber by hand layup compression technique. The wear characteristics of polypropylene matrix composites were tested by dry sliding condition. The test was carried out pin on disc apparatus, configured with hardened steel counter-face at elevated temperature. The load was applied 10 N to 30 N with the interval of 10 N and varying of sliding speed 300 rpm to 900 rpm with the interval of 300 rpm for the time period of 0-180 sec. The wear rate was decreases with addition of alumina nano particle and the frictional force was increases due to basalt Fiber content present in the composites. The co-efficient of friction was increases 0.1 to 0.66 under normal loading condition.
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Road Vehicles - Friction Materials - Finished Brake Pad Normalized Elastic Constant of Friction Material

Brake Linings Standards Committee
  • Ground Vehicle Standard
  • J3175_201911
  • Current
Published 2019-11-20 by SAE International in United States
This SAE standard specifies a method for testing and measuring a normalized elastic constant of brake pad assemblies using ultrasound. This document applies to disc brake pad assemblies and its coupons or segments used in road vehicles.
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Friction Material Elastic Constants Determination through FRF Measurements and Optimization

Brake NVH Standards Committee
  • Ground Vehicle Standard
  • J3013_201911
  • Current
Published 2019-11-20 by SAE International in United States
This SAE Standard specifies necessary procedures and control parameters in estimating anisotropic elastic constants of friction material based on pad assembly FRF measurements and optimization. It is intended to provide a set of elastic constants as inputs to brake NVH simulation, with the objective of ensuring pad assembly vibration correlation between simulation and measurements.
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