WorldWideScience

Sample records for automotive brake disc

  1. The mechanism of changes in the surface layer of grey cast iron automotive brake disc

    OpenAIRE

    Adam Polak; Janusz Grzybek

    2005-01-01

    The aim of the study was to create a model, describing the run of tribological processes in the surface layer of grey cast iron automotive brake discs. Grey cast iron discs mating with non-asbestos organic brake pads were chosen for the investigations, as the most widely used materials in car brakes. Samples for surface analysis were prepared from disc operating in stand and road conditions. Stand tests were pin-on-disc kind. Operating parameters for the stand tests were chosen on the basis o...

  2. CFD Analysis of Automotive Ventilated Disc Brake Rotor

    Directory of Open Access Journals (Sweden)

    Amol V. More

    2014-04-01

    Full Text Available Disc brakes work on the principle of friction by converting kinetic energy into heat energy. The key objective of a disc brake rotor is to accumulate this heat energy and dissipate it immediately. The effect of rotational speed on the aero-thermal performance is assessed. The rotor speed is observed to have substantial effect on the rotor performance. The heat dissipation and thermal performance of ventilated brake discs intensely be influenced by the aerodynamic characteristics of the air flow through the rotor passages. In order to investigate the aero-thermal performance of the ventilated disc brake at several altered driving speeds of the vehicle, the simulations were carried out at 3 different rotational speeds of 44rad/s 88 rad/s and 120 rad/s. The semi-automatic geometric model is created using the package Solid Works and the mesh for the model is done using ICEM CFD and the Post processing of the results is done using FLUENT-14.5.The results are discussed and presented in detail.

  3. The mechanism of changes in the surface layer of grey cast iron automotive brake disc

    Directory of Open Access Journals (Sweden)

    Adam Polak

    2005-12-01

    Full Text Available The aim of the study was to create a model, describing the run of tribological processes in the surface layer of grey cast iron automotive brake discs. Grey cast iron discs mating with non-asbestos organic brake pads were chosen for the investigations, as the most widely used materials in car brakes. Samples for surface analysis were prepared from disc operating in stand and road conditions. Stand tests were pin-on-disc kind. Operating parameters for the stand tests were chosen on the basis of results of our earlier research. Topography of brake disc surface was evaluated by surface roughness measurements. The surface layer was examined with use of metallography and scanning electron microscopy. In order to differentiate structures of grey cast iron brake discs SE and BSE modes were used in scanning electron microscopy. Chemical investigations of samples were done by X-ray analysis linked with SEM. Studies showed influence of grey cast iron structures on tribological processes taking place in a brake friction pair. The surface layer of grey cast iron discs was described and features and functions of separated structures were presented. On the basis of the obtained results a physical model of friction mechanism was created. Special attention was paid to the influence of graphite on the run of tribological processes and mechanism of compaction and removal of wear debris.

  4. Automotive brake squeal analysis with rotating finite elements of asymmetric disc in time

    Science.gov (United States)

    Kang, Jaeyoung

    2017-04-01

    The new finite element brake squeal model is proposed where the finite elements of a real brake disc rotate in time. Contact nodal forces between the rotating disc and stationary pads are allocated to the moving contact area at every time step. When the proposed model is applied to an asymmetric automotive brake disc, it becomes the periodic time-varying brake system. The stability boundary of the discrete time-varying system is numerically calculated by the Floquet theory. Also, the quasi-static linearized eigenvalue analysis is conducted to show that the unstable modes repeatedly appear at the short interval of the disc rotation angle. The results are consistent with the angle-dependent local phenomenon of squeal termed squeal periodicity in the squeal experiment. In the nonlinear time-domain analysis, the squeal vibration increases and then decays in time for the rotating mode shape functions. It demonstrates that the rotation of an asymmetric disc can change the nonlinear squeal behavior as well as the linear stability character drastically.

  5. Constitutive model for flake graphite cast iron automotive brake discs: induced anisotropic damage model under complex loadings

    Science.gov (United States)

    Augustins, L.; Billardon, R.; Hild, F.

    2016-09-01

    The present paper details an elasto-viscoplastic constitutive model for automotive brake discs made of flake graphite cast iron. In a companion paper (Augustins et al. in Contin Mech Thermodyn, 2015), the authors proposed a one-dimensional setting appropriate for representing the complex behavior of the material (i.e., asymmetry between tensile and compressive loadings) under anisothermal conditions. The generalization of this 1D model to 3D cases on a volume element and the associated challenges are addressed. A direct transposition is not possible, and an alternative solution without unilateral conditions is first proposed. Induced anisotropic damage and associated constitutive laws are then introduced. The transition from the volume element to the real structure and the numerical implementation require a specific basis change. Brake disc simulations with this constitutive model show that unilateral conditions are needed for the friction bands. A damage deactivation procedure is therefore defined.

  6. Structural optimization of an asymmetric automotive brake disc with cooling channels to avoid squeal

    Science.gov (United States)

    Wagner, Andreas; Spelsberg-Korspeter, Gottfried; Hagedorn, Peter

    2014-03-01

    Brake squeal is still a major issue in the automotive industry due to comfort complaints of passengers and resulting high warranty costs. Many measures to avoid squeal have been discussed in the engineering community reaching from purely passive measures like the increase of damping, e.g. by the application of shims, to the active or semiactive suppression of squeal. While active measures can be effective but are elaborate and therefore more expensive, passive measure are less complex in most cases. This leads to the necessity to develop passive, economic and robust measures to avoid squeal. Asymmetry of the brake rotor has been proposed to achieve this goal and the resulting split of all double eigenfrequencies of the brake rotor has lately been shown to stabilize the system.

  7. A Review of a Study on Disc Brake Noise

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    With the development of the automotive industry, disc brake noise has become an issue of growing concern to the automotive industry and customers. In this paper, the types of disc brake noise have been discussed. Ajter that, the theories and models that have been proposed as an explanation of brake squeal are reviewed. On the basis of these theories and models, some example simulations of disc brake squeal which use the Finite Element method and mathematical model have been introduced.

  8. Brake Fundamentals. Automotive Articulation Project.

    Science.gov (United States)

    Cunningham, Larry; And Others

    Designed for secondary and postsecondary auto mechanics programs, this curriculum guide contains learning exercises in seven areas: (1) brake fundamentals; (2) brake lines, fluid, and hoses; (3) drum brakes; (4) disc brake system and service; (5) master cylinder, power boost, and control valves; (6) parking brakes; and (7) trouble shooting. Each…

  9. Heat distribution in disc brake

    Science.gov (United States)

    Klimenda, Frantisek; Soukup, Josef; Kampo, Jan

    2016-06-01

    This article is deals by the thermal analysis of the disc brake with floating caliper. The issue is solved by numerically. The half 2D model is used for solution in program ADINA 8.8. Two brake discs without the ventilation are solved. One disc is made from cast iron and the second is made from stainless steel. Both materials are an isotropic. By acting the pressure force on the brake pads will be pressing the pads to the brake disc. Speed will be reduced (slowing down). On the contact surface generates the heat, which the disc and pads heats. In the next part of article is comparison the maximum temperature at the time of braking. The temperatures of both materials for brake disc (gray cast iron, stainless steel) are compares. The heat flux during braking for the both materials is shown.

  10. Stability analysis of automotive disc brake system with random parameters%随机参数汽车盘式制动器的稳定性分析

    Institute of Scientific and Technical Information of China (English)

    吕辉; 于德介

    2014-01-01

    针对不确定性参数汽车制动器噪声的抑制问题,基于随机参数分析理论,将响应面法与有限元复特征值技术相结合,提出了一种随机参数汽车制动器系统稳定性的分析方法。该方法用随机参数对制动器系统的不确定性进行描述,系统的摩擦系数、制动压力、制动盘厚度、制动片厚度和支撑背板的厚度参数分别采用随机变量表示;为提高分析效率,建立了包含随机变量的制动器不稳定特征值的响应面近似模型,进而根据系统特征值的随机特性对系统稳定性进行分析。用该方法对某车的浮钳盘式制动器系统进行研究,采用蒙特卡洛方法分析了随机参数正态分布假设下系统特征值的概率统计特性和参数灵敏度。结果表明:通过修改制动器支撑背板的厚度以提高支撑刚度,可有效改善制动器系统的稳定性,减小制动噪声的产生。%To suppress the brake noises of an automotive disc brake system with uncertain parameters ,a stability analysis method of automotive brake systems is presented in this paper .The essential idea of this method is to combine the RSM (Re-sponse Surface Method) and complex eigenvalue analysis techniques with random parameters introduced to describe such uncer-tainties in the brake system as friction coefficients ,brake pressure ,disc thickness ,pad thickness and backplate thickness .In order to improve the analysis efficiency ,RSM is used to build up the approximation models to express the functional relation-ships between the unstable eigenvalues and the system parameters ,which makes it available to study the stability of the brake system according to the random characteristics of the unstable eigenvalues .The stability analysis of a float caliper disc brake system is carried out by the proposed method with the random parameters assumed to follow normal distributions .The statisti-cal characteristics and the sensitivities

  11. A review of automotive disc brake squeal%汽车盘式制动器尖叫研究进展

    Institute of Scientific and Technical Information of China (English)

    吕红明; 张立军; 余卓平

    2011-01-01

    Disc brake squeal is one of the most difficult quality issues concerned by automotive manufacturers and researchers.It is of critical importance to study squeal generation mechanism, predict brake squeal performance and propose suppressing measures in product development phase for decreasing noise pollution, satisfying customers'requirements, accelerating new product development to improve automobile competitiveness.The recent research advances were reviewed in the aspects of squeal generation mechanisms, analysis methods, influence factors and new technologies.Latest developments showed that disc brake squeal is caused with complicated mechanisms and influenced with many factors; utilizing modern design methods of complex eigenvalue analysis and transient dynamics analysis combined with onroad and bench tests is an important way to analyze brake vibration characteristics and develop disc brakes with lower squeal propensity.The existing problems and the further study needed in the future were finally discussed.%盘式制动器的制动尖叫是汽车工业界备受关注的质量问题,也是学术研究领域的一个热点和难点课题.研究盘式制动器尖叫的产生机理,在制动器设计开发阶段进行尖叫预估,并提出抑制措施,对于降低噪音污染、满足顾客要求、加快制动器的产品开发进度,乃至提高汽车产品竞争力,都具有十分重要的意义.从制动尖叫的产生机理、数值分析方法、试验研究方法、影响因素以及尖叫抑制新技术等方面对盘式制动器尖叫的近期研究进展进行综述,众多的研究表明盘式制动器尖叫存在复杂的产生机理,并受到多种因素的影响,利用复特征值和瞬态动力学方法,结合实车道路试验和台架试验,是研究制动尖叫机理、开发低尖叫倾向产品的重要途径.最后总结现有研究存在的问题并对进一步的研究作出展望.

  12. Numerical Modeling of Disc Brake System in Frictional Contact

    Directory of Open Access Journals (Sweden)

    A. Belhocine

    2014-03-01

    Full Text Available Safety aspect in automotive engineering has been considered as a number one priority in development of new vehicle. Each single system has been studied and developed in order to meet safety requirement. Instead of having air bag, good suspension systems, good handling and safe cornering, there is one most critical system in the vehicle which is brake systems. The objective of this work is to investigate and analyse the temperature distribution of rotor disc during braking operation using ANSYS Multiphysics. The work uses the finite element analysis techniques to predict the temperature distribution on the full and ventilated brake disc and to identify the critical temperature of the rotor by holding account certain parameters such as; the material used, the geometric design of the disc and the mode of braking. The analysis also gives us, the heat flux distribution for the two discs.

  13. Thermal Modeling of Disc Brake Rotor in Frictional Contact

    Science.gov (United States)

    Ali, Belhocine; Ghazaly, Nouby Mahdi

    2013-01-01

    Safety aspect in automotive engineering has been considered as a number one priority in development of new vehicle. Each single system has been studied and developed in order to meet safety requirement. Instead of having air bag, good suspension systems, good handling and safe cornering, there is one most critical system in the vehicle which is brake systems. The objective of this work is to investigate and analyze the temperature distribution of rotor disc during braking operation using ANSYS Multiphysics. The work uses the finite element analysis techniques to predict the temperature distribution on the full and ventilated brake disc and to identify the critical temperature of the rotor. The analysis also gives us, the heat flux distribution for the two discs.

  14. CFD Analysis Of Straight Ventilated Disc Brake

    Directory of Open Access Journals (Sweden)

    Nikhil K

    2016-05-01

    Full Text Available Brakes are the key pieces of a vehicle that plays an active role in safety and performance of the system. The study of aerodynamic cooling of a disc brake in real working condition of vehicle is important in present situations. Brake discs get very hot quickly, so it should be dissipated properly through different modes of heat transfer. Contributions of these heat transfer modes are different in different type of problems. The cooling transfer rates are different in vane surface and frictional surface of a disc brake. Also the temperature varies in each small interval of braking time. So a transient problem simulation is important to study the cooling of a disc brake when a vehicle decelerates from a particular speed. ANSYS CFX tool is used for the simulation of this transient problem.

  15. Nonlinear transient and chaotic interactions in disc brake squeal

    Science.gov (United States)

    Oberst, S.; Lai, J. C. S.

    2015-04-01

    In automotive disc-brake squeal, most numerical studies have been focussed on the prediction of unstable vibration modes in the frequency domain using the complex eigenvalue analysis. However, the magnitude of the positive real part of a complex eigenvalue is an unreliable indicator of squeal occurrence. Although nonlinearities have been shown to play a significant role in brake squeal, transient nonlinear time domain analyses have rarely been applied owing to high computational costs. Here the complex eigenvalue analysis, the direct steady-state analysis and the transient nonlinear time domain analysis are applied to an isotropic pad-on-disc finite element model representing a simple model of a brake system. While in this investigation, in-plane pad-mode instabilities are not detected by the complex eigenvalue analysis, the dissipated energy obtained by the direct steady-state analysis of the model subjected to harmonic contact pressure excitation is negative at frequencies of pad modes, indicating a potential for instabilities. Transient nonlinear time domain analysis of the pad and disc dynamics reveal that in-plane pad vibrations excite a dominant out-of-plane disc mode. For intermittently chaotic pad motion, the disc dynamics is quasi-periodic; and for chaotic motion of the pad, a toroidal attractor is found for the disc's out-of-plane motion. Nonlinear interactions between the pad and the disc highlight that different parts in a brake system display different dynamic behaviour and need to be analysed separately. The type II intermittency route to chaos could be the cause for the experimentally observed instantaneous mode squeal.

  16. Study of heat transfer on front– and back-vented brake discs

    Directory of Open Access Journals (Sweden)

    Supachai Lakkam

    2013-12-01

    Full Text Available A brake disc plays an important role in the automotive industry since it concerns directly with safety. In order to develop proper heat ventilation a wide range of brake discs have been designed. Different types of physical brake disc geometries, as front- and back-vented brake discs, affect the heat ventilation directly. This is a vital factor of the brake’s capability. We recognized the importance of this circumstance and therefore attempted to create a test to investigate the temperature gradient of the brake disc in order to evaluate the coefficients of heat convection. The coefficients were modified by the change of temperature distribution in both brake discs under the forced heat convection in steady state conditions. However, the heat radiation value does not take into account that the heat convection is dominated by the physical geometry of the brake disc. To set up the experimental test for investigating the heat transfer by convection the JASO C406 standard is adopted. The experimental results in terms of heat convection coefficients are used in the numerical simulation via the finite element method in order to study the temperature diffusion and heat ventilation of front and back-vented brake discs. Conse-quently, the experimental results reveal that the overall heat convection coefficients of the front-vented brake disc are higher than these of the back-vented one. In other words the simulation yields that the front-vented brake disc allows stronger heat ventilation than its compared object, leading to larger temperature differences between outboard and inboard rotors, resulting in more thermal stress. This makes it more susceptible to be damaged during operation.

  17. Investigation of the coatings applied onto brake discs on disc-brake pad pair

    Directory of Open Access Journals (Sweden)

    I. Kiliçaslan

    2009-07-01

    Full Text Available While braking, according to the severity of it, thermal, metallurgical, constructive and tribological occurrences emerge on the brake disc-pad interface. In this study, NiCr was sprayed as bonding layer onto the discs, one ofwhich was coated with Al2O3-TiO2 by plasma spray and the other was coated with NiCr-Cr3C2 by High Velocity Oxygen Fuel (HVOF. In addition, the discs were tested with inertia dynamometer according to SAE’s J2522 testing procedure. The measurements showed that although the pads of the coated discs were exposed to higher braking temperatures, friction coefficient of the disc coated with NiCr- Cr3C2 was obtained 6 % higher compared to the original disc.

  18. RESEARCH ON AUTOMOTIVE BRAKE DISCS OF SiCP/Al COMPOSITE%SiC颗粒增强铝基复合材料制动盘的研究

    Institute of Scientific and Technical Information of China (English)

    齐海波; 丁占来; 樊云昌; 姜稚清

    2001-01-01

    采用半固态搅拌熔炼-液态模锻工艺制备了与Santana轿车前制动器相匹配的SiC颗粒增强铝基复合材料制动盘,对该制动盘进行了材料拉伸性能和微观结构分析,并在SCHENCK制动试验台上进行了制动性能和制动磨损试验。结果表明,复合材料的拉伸性能优于传统制动盘材料HT250铸铁;在各种制动工况条件下,复合材料制动盘对制动衬片的摩擦系数均在大众公司企业标准规定的范围之内,且较稳定;此外,复合材料制动盘质轻、耐磨,制动噪音小、温升低,运转平稳;因此,可望以其替代传统的铸铁制动盘,提高制动器的安全可靠性和服役寿命,减轻轿车悬挂系统的重量,降低油耗。%The SiCP/Al composite brake disc designed for the front brake of SANTANA cars was prepared by semi-solid stirring melting and liquid forging. The tensile properties and microstructures of the disc materials were examined, and the tribological-wear performances of the disc were tested on the SCHENCK brake testing system made in Germany. The results show that the tensile properties of the composites are superior to those of the conventional disc material, grey cast iron; and that under different braking conditions, the friction coefficients of the composite disc against the conventional brake pad are within the range specified by the standard of VOLKSWAGEN company and with small fluctuations. It is also found that the brake disc made of the composite has such advantages as light weight, high wear resistance, low braking noise and low braking temperature rises, smooth operating, etc. Hence, it is hopeful to substitute the composite disc for the traditional cast iron disc to increase reliability and to prolong the survice life of the car brake, to lighten the weight of the hanging system, and thus, to decrease gas expenditure of cars.

  19. Research on Heat-Mechanical Coupling of Ventilated Disc Brakes under the Condition of Emergency Braking

    Science.gov (United States)

    Tan, Xuelong; Zhang, Jian; Tang, Wenxian; Zhang, Yang

    Taking the ventilated disc brake in some company as research object, and using UG to build 3D models of brake disc and pad, and making use of ABAQUS/Standard to set up two parts' finite element model, via the decelerated motion of actual simulation brake disc, which gets ventilated disc brake in the case of emergency breaking in time and space distribution of conditions of temperature and stress field, summarizes the distribution of temperature field and stress field, proves complex coupling between temperature, stress, and supplies the direct basis for brake's fatigue life analysis.

  20. Quality control of cast brake discs

    Directory of Open Access Journals (Sweden)

    M. Stawarz

    2008-04-01

    Full Text Available The largest industrial application so far have the gray cast irons which are characterized by low tensile and bending strength, while at the same time they have good ultimate comprehensive strength. Additionally, the fatigue strength of gray cast irons is comparatively low and they are only to some extend sensitive for the surface waters effects. Cast iron is the material, which is comparatively easy to be processed, and for this reason – it is not expensive. Brake discs are exploited in particularly hard conditions. They must be resistant both against the thermal fatigue and abrasion wearing (at dry friction as well as against seizing, corrosion and mechanical load [1-3]. The gray cast iron, better than other materials, fulfills all the requirements necessary for making the material for the casts resistant against such tough conditions. This work reflects the researches aiming to define the quality of cast brake discs (ventilated and non-ventilated ones upon a period of their exploitation in real conditions. The following researches were performed: evaluations of the disc surface condition, measurement of disc thickness, examination of run – out flank and metallographic analysis. In order to more detailed recognition of mechanisms and reasons of brake discs wearing in real conditions, one should conduct additional examinations: computer analysis of the microstructure, chemical composition analysis, etc., as well as study of the technology of their production in foundries, where they are manufactured [4]. By obtaining the full set of the mentioned above data one can draw final conclusions and remove causes of possible defects.

  1. HEAT TRANSIENT TRANSFER ANALYSIS OF BRAKE DISC /PAD SYSTEM

    OpenAIRE

    Thuppal Vedanta, Srivatsan; Kora, Naga Vamsi Krishna

    2016-01-01

    Braking is mainly controlled by the engine. Friction between a pair of pads and a rotating disc converts the kinetic energy of the vehicle into heat. High temperatures can be reached in the system which can be detrimental for both, components and passenger safety. Numerical techniques help simulate load cases and compute the temperatures field in brake disc and brake pads. The present work implements a Finite Element (FE) toolbox in Matlab/Simulink able to simulate different braking manoeuvre...

  2. A Comparative Study on Automotive Brake Testing Standards

    Science.gov (United States)

    Kumbhar, Bhau Kashinath; Patil, Satyajit Ramchandra; Sawant, Suresh Maruti

    2016-06-01

    Performance testing of automotive brakes involves determination of stopping time, distance and deceleration level. Braking performance of an automobile is required to be ensured for various surfaces like dry, wet, concrete, bitumen etc. as well as for prolonged applications. Various brake testing standards are used worldwide to assure vehicle and pedestrian safety. This article presents methodologies used for automotive service brake testing for two wheelers. The main contribution of this work lies in comparative study of three main brake testing standards; viz. Indian Standards, Federal Motor Vehicle Safety Standards and European Economic Commission Standards. This study shall help the policy makers to choose the best criteria out of these three while formulating newer edition of testing standards.

  3. Comparative Frictional Analysis of Automobile Drum and Disc Brakes

    Directory of Open Access Journals (Sweden)

    H.P. Khairnar

    2016-03-01

    Full Text Available In the present work, a comparative frictional behaviour of drum brakes and disc brakes in automobiles has been investigated. The influential factors; contact force and friction radius were modeled for the estimation of the friction coefficient for drum as well as disc brakes. The effect of contact force and friction radius is studied with varying conditions of parameters; longitudinal force, caliper force and torque on piston side as well as non-piston side. The numerical results obtained have been compared with the similar obtained from virtual Matlab/Simulink models for drum and disc brakes. The results evidenced that friction radius predominantly affects brake pressure and thus the friction coefficient, also the increase in contact force resulted with decrease in friction coefficient both for drum and disc brakes. Further it has been found that disc brakes exhibit gradual decrease of friction coefficient due to the equitable distribution of braking effort while drum brake presents sudden variations in friction coefficient. It can be revealed that frictional behaviour of disc brake is more consistent than drum brake.

  4. Thermal analysis of both ventilated and full disc brake rotors with frictional heat generation

    Directory of Open Access Journals (Sweden)

    Belhocine A.

    2014-06-01

    Full Text Available In automotive engineering, the safety aspect has been considered as a number one priority in development of a new vehicle. Each single system has been studied and developed in order to meet safety requirements. Instead of having air bags, good suspension systems, good handling and safe cornering, one of the most critical systems in a vehicle is the brake system. The objective of this work is to investigate and analyze the temperature distribution of rotor disc during braking operation using ANSYS Multiphysics. The work uses the finite element analysis techniques to predict the temperature distribution on the full and ventilated brake discs and to identify the critical temperature of the rotor. The analysis also gives us the heat flux distribution for the two discs.

  5. Impact of Brake Pad Structure on Temperature and Stress Fields of Brake Disc

    Directory of Open Access Journals (Sweden)

    Guoshun Wang

    2013-01-01

    Full Text Available Utilizing ABAQUS finite element software, the study established the relationship between a brake pad structure and distributions of temperature and thermal stress on brake disc. By introducing radial structure factor and circular structure factor concepts, the research characterized the effect of friction block radial and circumferential arrangement on temperature field of the brake disc. A method was proposed for improving heat flow distribution of the brake disc through optimizing the position of the friction block of the brake pad. Structure optimization was conducted on brake pads composed of 5 or 7 circular friction blocks. The result shows that, with the same overall contact area of friction pair, an appropriate brake pad structure can make the friction energy distribute evenly and therefore lowers peak temperature and stress of the brake disc. Compared with a brake pad of 7 friction blocks, an optimized brake pad of 5 friction blocks lowered the peak temperature of the corresponding brake disc by 4.9% and reduced the highest stress by 10.7%.

  6. STUDY KOMPARASI LOST FOAM DAN KONVENSIONAL CASTING PRODUK DISC BRAKE

    OpenAIRE

    Yoso, Sumeru; -, Suyitno

    2014-01-01

    Disc brake component is a vital component with gray cast iron base material, it’s also fast lasting wearing part, so it has be replaced often. The disc brake replacement component in a local market is being supplied by the small scale local metal casting industries have the same quality as the genuine part.Disc brake making process is utilizing casting method inserting RCS core between drag and coup, than metal molten poured inside mold. The problem of this method is the product result often ...

  7. A Conceptual Design Method of Disc Brake Systems for Reducing Brake Squeal Considering Pressure Distribution Variations

    OpenAIRE

    松島, 徹; 泉井, 一浩; 西脇, 眞二

    2011-01-01

    This paper proposes a design optimization method for disc brake systems that specifically aims to reduce brake squeal, with robustness against changes on contact surface pressure distribution, based on the concept of First Order Analysis. First, a simplified analysis model is constructed in which a pressure distribution parameter is introduced, and the relationships between the occurrence of brake squeal and the characteristics of various components is then clarified, using the simplified mod...

  8. Brake squeal reduction of vehicle disc brake system with interval parameters by uncertain optimization

    Science.gov (United States)

    Lü, Hui; Yu, Dejie

    2014-12-01

    An uncertain optimization method for brake squeal reduction of vehicle disc brake system with interval parameters is presented in this paper. In the proposed method, the parameters of frictional coefficient, material properties and the thicknesses of wearing components are treated as uncertain parameters, which are described as interval variables. Attention is focused on the stability analysis of a brake system in squeal, and the stability of brake system is investigated via the complex eigenvalue analysis (CEA) method. The dominant unstable mode is extracted by performing CEA based on a linear finite element (FE) model, and the negative damping ratio corresponding to the dominant unstable mode is selected as the indicator of instability. The response surface method (RSM) is applied to approximate the implicit relationship between the unstable mode and the system parameters. A reliability-based optimization model for improving the stability of the vehicle disc brake system with interval parameters is constructed based on RSM, interval analysis and reliability analysis. The Genetic Algorithm is used to get the optimal values of design parameters from the optimization model. The stability analysis and optimization of a disc brake system are carried out, and the results show that brake squeal propensity can be reduced by using stiffer back plates. The proposed approach can be used to improve the stability of the vehicle disc brake system with uncertain parameters effectively.

  9. Infrared characterization of thermal gradients on disc brakes

    Science.gov (United States)

    Panier, Stephane; Dufrenoy, Philippe; Bremond, Pierre

    2003-04-01

    The heat generated in frictional organs like brakes and clutches induces thermal distortions which may lead to localized contact areas and hot spots developments. Hot spots are high thermal gradients on the rubbing surface. They count among the most dangerous phenomena in frictional organs leading to damage, early failure and unacceptable braking performances such as brake fade or undesirable low frequency vibrations called hot judder. In this paper, an experimental study of hot spots occurrence in railway disc brakes is reported on. The aim of this study was to better classify and to explain the thermal gradients appearance on the surface of the disc. Thermograph measurements with an infrared camera have been carried out on the rubbing surface of brake discs on a full-scale test bench. The infrared system was set to take temperature readings in snap shot mode precisely synchronized with the rotation of the disc. Very short integration time allows reducing drastically haziness of thermal images. Based on thermographs, a classification of hot-spots observed in disc brakes is proposed. A detailed investigation of the most damaging thermal gradients, called macroscopic hot spots (MHS) is given. From these experimental researches, a scenario of hot spots occurrence is suggested step by step. Thanks to infrared measurements at high frequency with high resolution, observations give new highlights on the conditions of hot spots appearance. Comparison of the experimental observations with the theoretical approaches is finally discussed.

  10. Product and process innovation of grey cast iron brake discs

    Energy Technology Data Exchange (ETDEWEB)

    Schorn, M. [Brembo S.P.A. (Italy)

    2006-07-01

    The brake disc out of grey cast iron often seems to be playing the role of the ''underdog'' in the technical examinations of the entire brake system. This is also reflected by the 25 year history of the {mu}-club. In a total of 93 presentations in those 25 years, only 3 were related to the topic of grey cast iron discs. This is not a correct relation to the importance of this component within the brake system. The disc, although per definition with a lower specific load than the pad, has the major task to store and dissipate the heat in which the kinetic energy of the vehicle is transformed. The disc also has a significant effect on NVH behaviour, particularly in the low frequency range. It also has a permanent fight with its weight as an unsprung mass. (orig.)

  11. Thermo-mechanical behaviour of heavy-duty disc brake systems

    OpenAIRE

    Chen, J. P.

    2001-01-01

    In heavy-duty disc brake systems, braking is a transient, non-linear and asymmetrical thermo-mechanical process. Surface cracking, rather than wear, is the major factor limiting the brake disc's life. The disc material (cast-iron), heat transfer boundary conditions and pad-disc frictional reactions are characteristically non-linear and asymmetrical during the friction process. Non-uniform deformation and surface cracks in brake discs result from the accumulation of excess...

  12. An Experimental Analysis of Brake Efficiency Using four Fluids in a Disc Brake System

    Directory of Open Access Journals (Sweden)

    Seth Daniel Oduro

    2013-02-01

    Full Text Available The paper studies disc brake failure in Mini-buses using an experimental analysis to test the maximum braking force when different brake fluids such as clean, less dirty, dirty and soapy water solution were used in the braking system. The experimental results clearly showed that the soap solution appears to be the best fluid as far as low viscosity and stability of viscosity with increase in temperature are concerned. However, the soap solution is not compatible with other fluid which makes it difficult to be substitute as a clean brake fluid. The result of the Thepra Universal Brake Testing Equipment used for the braking efficiency test indicated that a pedal brake of 117 kN produce a brake force of 0.96 kN for clean brake fluid, 0.91 kN for the less dirty, 0.85 kN for dirty and 1.44 kN for soap solution. The value of 1.44 kN which was achieved when the soap solution was used indicated a positive braking force and the indicating that soap solution could be used to produce a high pedal force within a very short time (about 10-30 min and can therefore be used only in case of emergency. The brake efficiency test indicated that under hot conditions the braking efficiency is reduced and the presence of air in the system renders the braking ineffective because higher pedal force was needed to be able to produce a significant braking force which is noted for causing brake failure.

  13. Tribological properties of C/C-SiC composites for brake discs

    Science.gov (United States)

    Jang, G. H.; Cho, K. H.; Park, S. B.; Lee, W. G.; Hong, U. S.; Jang, H.

    2010-02-01

    This study examines the friction and wear of ceramic matrix composites designed for use in automotive brake discs. The composites are produced by reinforcing a SiC matrix with carbon fibers using a liquid silicon infiltration method. C/C-SiC composites with two different compositions are fabricated to examine the compositional effect on the tribological properties. The tribological properties are evaluated using a scale dynamometer with a low-steel type friction material. The results show that the coefficient of friction is determined by the composition of the composite, which affects the propensity of friction film formation on the disc surface. A stable friction film on the disc surface also improves the wear resistance by diminishing the abrasive action of the disc. On the other hand, the friction film formation on the disc is affected by the applied pressure, and stable films are obtained at high pressures. This trend is prominent with discs with high Si content. However, both C/C/-SiC composites show superior performance in terms of the friction force oscillation, which is closely related to brake-induced vibration.

  14. Squeal analysis of ventilated disc brake using ansys

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Naser, Ahmed; Allam, Essam; Abouel-seoud, Shawki [Automotive and Tractors Engineering Department., Faculty of Engineering, Helwan University, Cairo (Egypt); Ahmed, Ibrahim; Allam, Sabry [Automotive and Tractors Technology Department, Faculty of Industrial Education, Helwan University, Cairo (Egypt)

    2012-07-01

    It is well-known that automobile brakes can generate several kinds of noises. Among them is squeal, a noise in the 1-15 kHz range. It is commonly accepted that brake squeal is initiated by instability due to the friction forces, leading to self excited vibrations. To predict the onset of brake instability, a modal analysis of the prestressed structure can be performed on an improved dynamic finite element model of ventilated disc brake with friction coupling. An unsymmetric stiffness matrix is a result of the friction coupling between the brake pad and disc; this may lead to complex eigenfrequencies. The complex eigenvalue method (Unsymmetric solver) used to analyse mode shapes associated with the predicted natural frequency. Creating the element of Matrix27 between the ventilated disc and pad was very important in studying the squeal of the coupled ventilated disc brake. The results demonstrated that the FEM for the coupled ventilated rotor and pad showed a good interaction between the non-linear contact and the linear modal analysis. Furthermore, the unsymmetric solver showed that the modes of the coupled disc-pad contained two types of mode. The first type was normal mode, which did not contain an imaginary part while the second type was complex mode that contained real and imaginary parts. Moreover, complex eigenvalue analysis predicted always more unstable modes than the number of squeal frequencies that really occur in the brake system. The maximum squeal index was observed at mode 16 and at frequency of 4083 Hz with instability of 480 sec-1. However; the tendency of instability (TOI) for the system at contact stiffness of 1 GN/m was 59 that gave the lowest instability of the system.

  15. Squeal analysis of ventilated disc brake using ansys

    Directory of Open Access Journals (Sweden)

    Ahmed Abdel-Naser, Ibrahim Ahmed, Essam Allam, Sabry Allam, Shawki Abouel-seoud

    2012-01-01

    Full Text Available It is well-known that automobile brakes can generate several kinds of noises. Among them is squeal, a noise in the 1-15 kHz range. It is commonly accepted that brake squeal is initiated by instability due to the friction forces, leading to self excited vibrations. To predict the onset of brake instability, a modal analysis of the prestressed structure can be performed on an improved dynamic finite element model of ventilated disc brake with friction coupling. An unsymmetric stiffness matrix is a result of the friction coupling between the brake pad and disc; this may lead to complex eigenfrequencies. The complex eigenvalue method (Unsymmetric solver used to analyse mode shapes associated with the predicted natural frequency. Creating the element of Matrix27 between the ventilated disc and pad was very important in studying the squeal of the coupled ventilated disc brake. The results demonstrated that the FEM for the coupled ventilated rotor and pad showed a good interaction between the non-linear contact and the linear modal analysis. Furthermore, the unsymmetric solver showed that the modes of the coupled disc-pad contained two types of mode. The first type was normal mode, which did not contain an imaginary part while the second type was complex mode that contained real and imaginary parts. Moreover, complex eigenvalue analysis predicted always more unstable modes than the number of squeal frequencies that really occur in the brake system. The maximum squeal index was observed at mode 16 and at frequency of 4083 Hz with instability of 480 sec-1. However; the tendency of instability (TOI for the system at contact stiffness of 1 GN/m was 59 that gave the lowest instability of the system.

  16. Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

    Science.gov (United States)

    Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

    2016-02-01

    The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

  17. Control strategy of disc braking systems for downward belt conveyors

    Institute of Scientific and Technical Information of China (English)

    Hou Youfu; Xie Fangwei; Huang Fei

    2011-01-01

    Reliability of braking systems is a key requirement to ensure the safety of in using downward belt conveyor brakes.By analyzing and comparing three commonly used braking velocity curves,we conclude that the Harrison curve is the best.Given the characteristics of a downward belt conveyor,we studied the control in a closed-loop velocity,a conventional PID method and an optimal PID control method.We used MATLAB/Simulink to simulate the three control methods.Our simulation results show that optimal PID control is especially suitable for disc braking systems.To verify the results from theoretical analysis and simulation,a multifunctional test-bed was developed to simulate the braking process of a disc brake system.Our experimental results demonstrate that the optimal PID control can make the output velocity to follow a preset velocity correctly with only small fluctuations,meeting the requirements of a flexible brake for a belt conveyor.

  18. ANALYSIS OF FAILURE MECHANISM IN MULTIPLE DISC WET BRAKES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    By the numberical calculation of dynamic lining pressure distributions,temperature fields and thermal stress fields of steel plates,a method using nonlinear finite element techniques to analyze failure mechanism of a multiple disc wet brake is detailed ,and some measures for combatting these failures are provided.

  19. Evaluation of palm kernel fibers (PKFs for production of asbestos-free automotive brake pads

    Directory of Open Access Journals (Sweden)

    K.K. Ikpambese

    2016-01-01

    Full Text Available In this study, asbestos-free automotive brake pads produced from palm kernel fibers with epoxy-resin binder was evaluated. Resins varied in formulations and properties such as friction coefficient, wear rate, hardness test, porosity, noise level, temperature, specific gravity, stopping time, moisture effects, surface roughness, oil and water absorptions rates, and microstructure examination were investigated. Other basic engineering properties of mechanical overload, thermal deformation fading behaviour shear strength, cracking resistance, over-heat recovery, and effect on rotor disc, caliper pressure, pad grip effect and pad dusting effect were also investigated. The results obtained indicated that the wear rate, coefficient of friction, noise level, temperature, and stopping time of the produced brake pads increased as the speed increases. The results also show that porosity, hardness, moisture content, specific gravity, surface roughness, and oil and water absorption rates remained constant with increase in speed. The result of microstructure examination revealed that worm surfaces were characterized by abrasion wear where the asperities were ploughed thereby exposing the white region of palm kernel fibers, thus increasing the smoothness of the friction materials. Sample S6 with composition of 40% epoxy-resin, 10% palm wastes, 6% Al2O3, 29% graphite, and 15% calcium carbonate gave better properties. The result indicated that palm kernel fibers can be effectively used as a replacement for asbestos in brake pad production.

  20. Thermo-Mechanical Simulation of Brake Disc Frictional Character by Moment of Inertia

    Directory of Open Access Journals (Sweden)

    Fei Gao

    2014-01-01

    Full Text Available The distribution of temperatures gradient and thermal stress of brake disc has been simulated by FEM code to make brake disc thermal stress more homogenously. In this study, using moment of inertia to simulate the realistic brake process instead of theoretically predefines the train deceleration rate, nonlinear deceleration rate and thermo-mechanical behavior has been revealed. The FEM models build upon LS-DYNA® thermo-mechanical code and contact algorithm. Non-uniform temperature alone disc radial direction was caused by severe friction in short time and the low heat transfer coefficient of its material. Parametric analysis for disc brakes have been carried out by comparison of grouped brake applications conform to UIC code, the main factor cause the high temperature gradient and thermal stress of brake disc is brake force and its initial speed.

  1. A low cost, light weight cenosphere–aluminium composite for brake disc application

    Indian Academy of Sciences (India)

    V Saravanan; P R Thyla; S R Balakrishnan

    2016-02-01

    The commonly used composite material for brake rotor consists of silicon carbide (SiC) or aluminium oxide (Al$_2$O$_3$) particles which are more expensive. The weight of conventionally used composite is more compared to base alloy. The aim of this paper is to develop a light weight material for brake disc applications thereby substituting base alloy and conventional composite. This analysis led to 10 vol% cenosphere reinforced aluminium alloy (AA) 6063 composite as the most appropriate material for brake disc. To ensure the manufacturability of composite, composite brake rotor was casted using the sand casting technique and was machined to achieve the final component. Thermal capability of brake disc was ensured by studying temperature variation through vehicle testing procedure of disc brake. Cost reduction is one of the important benefit acquired using cenosphere reinforced composite. This was ensured by cost estimation and analysis. The cost estimated to manufacture the AA6063 brake disc was compared with composite cost.

  2. Thermo-Mechanical Simulation of Brake Disc Frictional Character by Moment of Inertia

    OpenAIRE

    Fei Gao

    2014-01-01

    The distribution of temperatures gradient and thermal stress of brake disc has been simulated by FEM code to make brake disc thermal stress more homogenously. In this study, using moment of inertia to simulate the realistic brake process instead of theoretically predefines the train deceleration rate, nonlinear deceleration rate and thermo-mechanical behavior has been revealed. The FEM models build upon LS-DYNA® thermo-mechanical code and contact algorithm. Non-uniform temperature alone disc ...

  3. 基于ANSYS的盘式制动器制动噪声分析%The Nose Analysis of Disc Brake Based on Ansys Soft

    Institute of Scientific and Technical Information of China (English)

    李兵; 王庆波; 曲波; 周志刚; 丛茜

    2012-01-01

    针对汽车盘式制动器制动过程中的噪声问题,以振动噪声理论为基础,通过3D绘图软件Pro/e建立制动盘和摩擦片模型,通过Ansys有限元软件对其进行了动力学分析,提取了其前15阶模态并进行了分析,发现制动盘等零件的某几阶模态是引起制动尖叫的主要诱因,对降低制动过程中出现的尖叫以及结构的优化有指导帮助作用.%According to automotive disc brake noise problems, based on noise and vibration theory, the models of brake disc and friction plate was proposed, and the kinetic response of disc and friction plate was analyzed. Through the analysis of 15 modes, the main incentives of causing brake squeal were found, namely, some modes of disc brake and plate. To reduce the brake appeared in the process of screaming and the optimization of the structure, it is a helpful guidance.

  4. Frictional and heat resistance characteristics of coconut husk particle filled automotive brake pad

    Science.gov (United States)

    Bahari, Shahril Anuar; Chik, Mohd Syahrizul; Kassim, Masitah Abu; Som Said, Che Mohamad; Misnon, Mohd Iqbal; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    The objective of this study was to determine the friction and heat resistance characteristics of automotive brake pad composed with different sizes and percentages of coconut husk particle. The materials used were phenolic resin (phenol formaldehyde) as binder, copper, graphite and brass as friction producer/modifiers, magnesium oxide as abrasive material, steel and barium sulfate as reinforcement while coconut husk particle as filler. To obtain particle, the coconut husk was ground and dried to 3% moisture content. Then the coconut husk particle was screened using 80 mesh (to obtain coarse dust) and 100 mesh (to obtain fine dust). Different percentages of particle, such as 10 and 30% were used in the mixture of brake pad materials. Then the mixture was hot-pressed to produce brake pad. Chase machine was used to determine the friction coefficient in friction resistance testing, while thermogravimetric analyzer (TGA) machine was used to determine the heat decomposition values in heat resistance testing. Results showed that brake pad with 100 mesh and 10% composition of coconut husk particle showed the highest friction coefficient. For heat resistance, brake pad with 100 mesh and 30% composition of coconut husk dust showed the highest decomposition temperature, due to the high percentage of coconut husk particle in the composition, thus increased the thermal stability. As a comparison, brake pad composed with coconut husk particle showed better heat resistance results than commercial brake pad.

  5. 基于有限元技术的汽车盘式制动器性能研究%Performance Research of Automobile Disc Brake based on Finite Element Technology

    Institute of Scientific and Technical Information of China (English)

    何亚峰

    2012-01-01

    盘式制动器由于散热性能和制动效能好等优点,被广泛应用于汽车行业中.利用大型AN-SYS有限元平台对汽车盘式制动器进行了应力应变场量数值分析,通过改变制动器设计参数(制动力、摩擦因数、制动片厚度)得到了设计参数与制动性能的影响关系,其结果可为汽车制动器设计提供一定的理论依据和参考.%Due to good cooling and braking performance, the disc brake is widely used in automotive industry. The numerical analysis of stress and strain field for automobile disc brake is carried out by using ANSYS finite element platform, ihe influence relalionship of design parameters and braking performance is obtained by changing design pa rametere of the brake (braking force, friction coefficienl, brake pad thickness), A certain theoretical basis and refer ence for the automotive brake designer is provided from the results.

  6. Numerical Analysis of Temperature Field in a Disc Brake at Different Cover Angle of the Pad

    Directory of Open Access Journals (Sweden)

    Grześ Piotr

    2014-12-01

    Full Text Available In the paper an influence of the cover angle of the pad on temperature fields of the components of the disc brake is studied. A three-dimensional finite element (FE model of the pad-disc system was developed at the condition of equal temperatures on the contacting surfaces. Calculations were carried out for a single braking process at constant deceleration assuming that the contact pressure corresponds with the cover angle of the pad so that the moment of friction is equal in each case analysed. Evolutions and distributions of temperature both for the contact surface of the pad and the disc were computed and shown.

  7. Structural and Thermal Analysis of Automotive Disc Brake Rotor

    Directory of Open Access Journals (Sweden)

    Belhocine Ali

    2014-03-01

    Full Text Available Głównym celem pracy jest analiza zjawisk termomechanicznych w obszarze suchego styku pomiedzy tarcza hamulca a klockiem ciernym wystepujacych w fazie hamowania. Strategia symulacji jest oparta na oprogramowaniu ANSYS11. Wyniki modelowania stanów przejsciowych temperatury w tarczy hamulca wykorzystano do identyfikacji geometrycznych współczynników projektowych, uzytych do instalacji systemu wentylacji. Sprzezona analiza strukturalno-termiczna jest nastepnie uzyta do wyznaczenia deformacji tarczy, naprezenia Von Misses’a, oraz rozkładu cisnienia kontaktowego w klockach ciernych. Wyniki analizy wykazuja zadowalajaca zgodnosc z podobnymi podawanymi w literaturze.

  8. On airborne nano/micro-sized wear particles released from low-metallic automotive brakes.

    Science.gov (United States)

    Kukutschová, Jana; Moravec, Pavel; Tomášek, Vladimír; Matějka, Vlastimil; Smolík, Jiří; Schwarz, Jaroslav; Seidlerová, Jana; Safářová, Klára; Filip, Peter

    2011-04-01

    The paper addresses the wear particles released from commercially available "low-metallic" automotive brake pads subjected to brake dynamometer tests. Particle size distribution was measured in situ and the generated particles were collected. The collected fractions and the original bulk material were analyzed using several chemical and microscopic techniques. The experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm were released into the air. The numbers of nanoparticles (release of nanoparticles was measured when the average temperature of the rotor reached 300°C, the combustion initiation temperature of organics present in brakes. In contrast to particle size distribution data, the microscopic analysis revealed the presence of nanoparticles, mostly in the form of agglomerates, in all captured fractions. The majority of elements present in the bulk material were also detected in the ultra-fine fraction of the wear particles.

  9. Thermomechanical Simulation of Wear and Hot Bands in a Disc Brake by Adopting an Eulerian Approach

    OpenAIRE

    Rashid, Asim; Strömberg, Niclas

    2013-01-01

    In this paper frictional heating of a disc brake is simulated while taking wear into account. By performing thermomechanical finite element analysis, it is studied how the wear history will influence the development of hot bands. The frictional heat analysis is based on an Eulerian formulation of the disc, which requires significantly lower computational time as compared to a standard Lagrangian approach. A real disc-pad system to a heavy truck is considered, where complete three-dimensional ...

  10. Climate Based Performance of Carbon-Carbon Disc Brake for High Speed Aircraft Braking System

    Directory of Open Access Journals (Sweden)

    R. M. Mohanty

    2013-09-01

    Full Text Available Carbon composite brake discs are lighter, economical, and have excellent high energy friction characteristics. These have twice thermal capability compared to steel, remain unaffected by thermal shocks and mechanical fatigue. These are highly useful in emergency breaking situations. Prior to this work, two dimensional (2D reinforced carbon composite laminates were prepared through pitch impregnation process. In an effort to protect the exposed non frictional surface from high temperature service degradations, multilayered ceramic coating systems were developed on 2D composite. Oxidation studies have been carried out on these systems viz., C-SiC, C-SiC-MoSi2-Al2O3 and C-SiC-B4C. These were performed both in dynamic and static conditions up to 1200 °C in 60 per cent humid climate. The hardness, surface topography, developed phases and integrity of layers on the samples at various stages of the experiment have been characterized and analyzed. It was observed that C-SiC-B4C system performs well in the oxidizing environment.Defence Science Journal, 2013, 63(5, pp.531-538, DOI:http://dx.doi.org/10.14429/dsj.63.3932

  11. A Computational Study on the Use of an Aluminium Metal Matrix Composite and Aramid as Alternative Brake Disc and Brake Pad Material

    Directory of Open Access Journals (Sweden)

    Nosa Idusuyi

    2014-01-01

    Full Text Available A computational model for the heat generation and dissipation in a disk brake during braking and the following release period has been formulated. The model simulates the braking action by investigating the thermal behaviour occurring on the disc and pad surfaces during this period. A comparative study was made between grey cast iron (GCI, asbestos, Aluminium metal matrix composite (AMC, and aramid as brake pad and disc materials. The braking process and following release period were simulated for four material combinations, GCI disc and Asbestos pad, GCI disc and Aramid pad, AMC disc and Asbestos pad, AMC disc and Aramid pad using COMSOL Multiphysics software. The results show similarity in thermal behaviour at the contact surface for the asbestos and aramid brake pad materials with a temperature difference of 1.8 K after 10 seconds. For the brake disc materials, the thermal behaviour was close, with the highest temperature difference being 9.6 K. The GCI had a peak temperature of 489 K at 1.2 seconds and AMC was 465.5 K but cooling to 406.4 K at 10 seconds, while the GCI was 394.7 K.

  12. Advanced Emergency Braking Controller Design for Pedestrian Protection Oriented Automotive Collision Avoidance System

    Directory of Open Access Journals (Sweden)

    Guo Lie

    2014-01-01

    Full Text Available Automotive collision avoidance system, which aims to enhance the active safety of the vehicle, has become a hot research topic in recent years. However, most of the current systems ignore the active protection of pedestrian and other vulnerable groups in the transportation system. An advanced emergency braking control system is studied by taking into account the pedestrians and the vehicles. Three typical braking scenarios are defined and the safety situations are assessed by comparing the current distance between the host vehicle and the obstacle with the critical braking distance. To reflect the nonlinear time-varying characteristics and control effect of the longitudinal dynamics, the vehicle longitudinal dynamics model is established in CarSim. Then the braking controller with the structure of upper and lower layers is designed based on sliding mode control and the single neuron PID control when confronting deceleration or emergency braking conditions. Cosimulations utilizing CarSim and Simulink are finally carried out on a CarSim intelligent vehicle model to explore the effectiveness of the proposed controller. Results display that the designed controller has a good response in preventing colliding with the front vehicle or pedestrian.

  13. ENERGY-LOADING OF DISKS IN FRICTION PAIRS OF “DISC-PAD” OF BRAKING DEVICES IN VEHICLES (part two

    Directory of Open Access Journals (Sweden)

    Krasin P. S.

    2015-06-01

    Full Text Available In the materials of the article we mention the regularities of changes in the volume and surface solid temperature gradients and self-ventilated brake discs and illustrate their impact on the main operating parameters of the friction pairs of disk-to-pad brakes of the A 172 bus; the relationship between thermo-physical parameters of polished and matte surfaces with areas of brake discs of various types. The influence of the type of tests on the pairs of loaded with energy friction disk and pad brakes of the vehicle. We have set the intensity of heat exchange processes from the surfaces of the brake discs of various types. It is shown that this leads to increased surface temperature gradient. The volume and the surface temperature gradients of the brake discs were determined with the involvement of the hypothesis of summation of temperatures on the surface when you post the generated electric currents. It was found that in the surface layer of the working surface of a solid brake disc at its pulse heating under the influence of the temperature of the flash nucleate cracks due to the thermal fatigue of the material of the disk. The features of the design of the brake discs were considered as well. On the basis of the calculation and the experimental data we have shown a correlation between the emissivity of brushed and polished surfaces and their areas in the disk-to-pad brakes when using solid and self-ventilated discs

  14. Design and Development of Hydraulic Disc Brake Systems for Well Servicing Rig Drawworks

    Institute of Scientific and Technical Information of China (English)

    Gao xiangqian; Zhou Yongxia

    1996-01-01

    @@ The conventional band brakes have been known to be important but also the most unlnerable part in servicing rig deawworks.. The failures in braking and releasing operations haven't well been avoided. There have evidently existed the problems of difficult operation and inconvenient maintenance in this connection. The use of power-assisted hydraulic cylinders or pneumatic cylinders can not meet the requirements of operations either. Since the late 1980s, we have cooperated with Shengli oilfields and others in the successful design and development of PST25 hydraulic disc brake systems for well servicing rig in a fully closed working state.

  15. Guidelines for numerical vibration and acoustic analysis of disc brake squeal using simple models of brake systems

    Science.gov (United States)

    Oberst, S.; Lai, J. C. S.; Marburg, S.

    2013-04-01

    Brake squeal has become of increasing concern to the automotive industry but guidelines on how to confidently predict squeal propensity are yet to be established. While it is standard practice to use the complex eigenvalue analysis to predict unstable vibration modes, there have been few attempts to calculate their acoustic radiation. Here guidelines are developed for numerical vibration and acoustic analysis of brake squeal using models of simplified brake systems with friction contact by considering (1) the selection of appropriate elements, contact and mesh; (2) the extraction of surface velocities via forced response; and (3) the calculation of the acoustic response itself. Results indicate that quadratic tetrahedral elements offer the best option for meshing more realistic geometry. A mesh has to be sufficiently fine especially in the contact region to predict mesh-independent unstable vibration modes. Regarding the vibration response, only the direct, steady-state method with a pressurised pad and finite sliding formulation (allowing contact separation) should be used. Comparison of different numerical methods suggest that a obroadband fast multi-pole boundary element method with the Burton-Miller formulation would efficiently solve the acoustic radiation of a full brake system. Results also suggest that a pad lift-off can amplify the acoustic radiation similar to a horn effect. A horn effect is also observed for chamfered pads which are used in practice to reduce the number and strength of unstable vibration modes. These results highlight the importance of optimising the pad shape to reduce acoustic radiation of unstable vibration modes.

  16. Identification and Modeling of Automotive Electrical Parking Brake System for SiL Simulation

    Institute of Scientific and Technical Information of China (English)

    PENG Yi-qiang; LI Wei; ZHANG Jin-lei

    2008-01-01

    To evaluate the software behavior of the electronic control unit (ECU) of automotive electrical parking brake (EPB), a software-in-the-loop (SiL) simulation system is built. The EPB is simulated by ARX (auto-regressive with auxiliary input) model, ARMAX (auto-regressive moving average with auxiliary input) model, and NNARMAX (neural network ARMAX) model. By system identification, the ARX(3,4,2), ARX(4,4,2), ARMAX(3,3,1,1), and ARMAX(4,4,3,2) models are derived. Validation results show that the four-order ARMAX model and the NNARMAX model better simulate the actuator of the EPB.

  17. Fundamentals of automotive and engine technology standard drives, hybrid drives, brakes, safety systems

    CERN Document Server

    2014-01-01

    Hybrid drives and the operation of hybrid vehicles are characteristic of contemporary automotive technology. Together with the electronic driver assistant systems, hybrid technology is of the greatest importance and both cannot be ignored by today’s car drivers. This technical reference book provides the reader with a firsthand comprehensive description of significant components of automotive technology. All texts are complemented by numerous detailed illustrations. Contents History of the automobile.- History of the Diesel engine.- Areas of use for Diesel engines.- Basic principles of the Diesel engine.- Basic principles of Diesel fuel-injection.- Basic principles of the gasoline engine.- Inductive ignition system.- Transmissions for motor vehicles.- Motor vehicle safety.- Basic principles of vehicle dynamics.- Car braking systems.- Vehicle electrical systems.- Overview of electrical and electronic systems in the vehicle.- Control of gasoline engines.- Control of Diesel engines.- Lighting technology.- Elec...

  18. Thermomechanical behavior of dry contacts in disc brake rotor with a grey cast iron composition

    Directory of Open Access Journals (Sweden)

    Belhocine Ali

    2013-01-01

    Full Text Available The main purpose of this study is to analysis the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase. The simulation strategy is based on the calculation code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

  19. Mechanical testing and modelling of carbon-carbon composites for aircraft disc brakes

    Science.gov (United States)

    Bradley, Luke R.

    The objective of this study is to improve the understanding of the stress distributions and failure mechanisms experienced by carbon-carbon composite aircraft brake discs using finite element (FE) analyses. The project has been carried out in association with Dunlop Aerospace as an EPSRC CASE studentship. It therefore focuses on the carbon-carbon composite brake disc material produced by Dunlop Aerospace, although it is envisaged that the approach will have broader applications for modelling and mechanical testing of carbon-carbon composites in general. The disc brake material is a laminated carbon-carbon composite comprised of poly(acrylonitrile) (PAN) derived carbon fibres in a chemical vapour infiltration (CVI) deposited matrix, in which the reinforcement is present in both continuous fibre and chopped fibre forms. To pave the way for the finite element analysis, a comprehensive study of the mechanical properties of the carbon-carbon composite material was carried out. This focused largely, but not entirely, on model composite materials formulated using structural elements of the disc brake material. The strengths and moduli of these materials were measured in tension, compression and shear in several orientations. It was found that the stress-strain behaviour of the materials were linear in directions where there was some continuous fibre reinforcement, but non-linear when this was not the case. In all orientations, some degree of non-linearity was observed in the shear stress-strain response of the materials. However, this non-linearity was generally not large enough to pose a problem for the estimation of elastic moduli. Evidence was found for negative Poisson's ratio behaviour in some orientations of the material in tension. Additionally, the through-thickness properties of the composite, including interlaminar shear strength, were shown to be positively related to bulk density. The in-plane properties were mostly unrelated to bulk density over the range of

  20. Wear mechanism of disc-brake block material for new type of drilling rig

    Institute of Scientific and Technical Information of China (English)

    Xinhua WANG; Simin WANG; Siwei ZHANG; Deguo WANG

    2008-01-01

    To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and ele-mentary components of the brake block's wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechan-ism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Fe-abundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Fe-abundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same

  1. Optimal design of disc-type magneto-rheological brake for mid-sized motorcycle: experimental evaluation

    Science.gov (United States)

    Sohn, Jung Woo; Jeon, Juncheol; Nguyen, Quoc Hung; Choi, Seung-Bok

    2015-08-01

    In this paper, a disc-type magneto-rheological (MR) brake is designed for a mid-sized motorcycle and its performance is experimentally evaluated. The proposed MR brake consists of an outer housing, a rotating disc immersed in MR fluid, and a copper wire coiled around a bobbin to generate a magnetic field. The structural configuration of the MR brake is first presented with consideration of the installation space for the conventional hydraulic brake of a mid-sized motorcycle. The design parameters of the proposed MR brake are optimized to satisfy design requirements such as the braking torque, total mass of the MR brake, and cruising temperature caused by the magnetic-field friction of the MR fluid. In the optimization procedure, the braking torque is calculated based on the Herschel-Bulkley rheological model, which predicts MR fluid behavior well at high shear rate. An optimization tool based on finite element analysis is used to obtain the optimized dimensions of the MR brake. After manufacturing the MR brake, mechanical performances regarding the response time, braking torque and cruising temperature are experimentally evaluated.

  2. 汽车刹车盘性能综述%Review on brake discs performance

    Institute of Scientific and Technical Information of China (English)

    张小雪; 刘兰俊

    2012-01-01

    Brake disks,as a component to ensure the security are constantly submitted to relatively high temperature and high pressure during braking action. In order to effectively play braking effect, brake disks require some performance,such as excellent thermal transport ability,good wear resistance,high thermal fatigue performance and low brake squeal.The more A type graphite, the better thermal transport ability of cast iron .Thermal conductivity of cast iron is temperature inverse proportion function.Wear resistancenot is related to not only the matrix strength and hardness ,but also external factors,such as lubrication condition contact pressure and sliding distance. Crack resistance is attributed to thermal transport ability and strength and hardness.Brake squeal randomly occur,people do not understand its mechanism.The high performance of brake disc is obtained by Alloying 、advancing melting technology and proper Inoculation.%刹车盘做为保安件,为了有效起到制动作用,要求有优良的导热性、耐磨性、抗热疲劳性及小的刹车鸣叫.A型石墨数量越多,铸铁的导热性越好.铸铁的导热能力是温度的反比例函数.耐磨性不仅与基体的强度硬度有关,还与外界因素有关.材料的导热性能好,强度和硬度高,则抗裂能力强.可以通过合金化,提高熔炼工艺以及恰当的孕育,获得高性能的刹车盘.

  3. Design of Braking Caliper's Braking Torque in Hydraulic Disc Braking System%液压盘式刹车系统制动钳制动力矩的设计

    Institute of Scientific and Technical Information of China (English)

    高燕; 宋胜涛; 王跃军; 韩美香; 郭太清

    2012-01-01

    针对目前液压盘式刹车系统刹车力矩小,刹车性能不稳定等现状,基于老算法对制动转矩的计算原理设计了一种新算法,对制动钳的工作制动转矩,紧急制动转矩及驻车制动转矩,冗余安全设计等进行了计算.为提高液压盘式刹车系统的设计效率和安全系数,该算法从制动钳的工作原理出发,通过对制动钳的制动结构进行分析,以下放到井中的最重套管柱所形成的静制动转矩作为盘刹系统能满足的最小工作制动转矩为依据,通过验证计算结果,保障了液压盘式刹车系统的安全性和有效性.%The current braking torque of the hydraulic disc braking system is small and braking performance is instable.A new algorithm was designed based on the braking torque's calculation of the old algorithm.The work braking torque, emergency braking torque, park braking torque and the redundant safety design were calculated in this new algorithm.To improve the design efficiency and safety coefficient of the hydraulic disc braking system, the algorithm based on the working principle of the braking caliper, through the braking structure analysis of the braking caliper, according to the static braking torque formed by the heaviest casing string that put into the well could be taken as the minimum working braking torque which the disc braking system could meet.The safety and effectiveness of the hydraulic disc braking system are safeguarded through the authentication and calculation of the result.

  4. Control of Braking Noise of A Car Disc Brake%某型轿车盘式制动器制动噪声的控制

    Institute of Scientific and Technical Information of China (English)

    戢何民

    2011-01-01

    Bench test is made to a car diac brake, it is found in this test that braking noise frequency mainly occurs at 3 kHz. With FEA, vibration characteristic analysis is made to brake disc, brake caliper case, caliper bracket and friction pad. Test results indicate that 7-order vibration mode of brake caliper bracket is a major contributor of -braking noise. Structure of brake caliper bracket is modified, and bench test is made to the disc brake with the modified caliper bracket. The results show that cold state braking noise is reduced from 100.5 dB to 73.4 dB, meeting the requirement of noise limit of this vehicle.%对某型轿车盘式制动器进行了台架试验,发现该制动器主要制动噪声频率在3 kHz附近.采用有限元FEA分析手段对制动盘、制动钳壳体、制动钳支架和摩擦片进行了振动特性分析.结果表明,制动钳支架的7阶振动模态是导致制动噪声产生的原因之一.对制动钳支架结构设计进行了改进,并对装有改进后制动钳支架的盘式制动器进行了台架试验.结果表明,制动器冷态制动噪声从100.5 dB下降为73.4 dB,达到了该车型对制动器噪声的限值要求.

  5. A statistical approach to estimate the LYAPUNOV spectrum in disc brake squeal

    Science.gov (United States)

    Oberst, S.; Lai, J. C. S.

    2015-01-01

    The estimation of squeal propensity of a brake system from the prediction of unstable vibration modes using the linear complex eigenvalue analysis (CEA) in the frequency domain has its fair share of successes and failures. While the CEA is almost standard practice for the automotive industry, time domain methods and the estimation of LYAPUNOV spectra have not received much attention in brake squeal analyses. One reason is the challenge in estimating the true LYAPUNOV exponents and their discrimination against spurious ones in experimental data. A novel method based on the application of the ECKMANN-RUELLE matrices is proposed here to estimate LYAPUNOV exponents by using noise in a statistical procedure. It is validated with respect to parameter variations and dimension estimates. By counting the number of non-overlapping confidence intervals for LYAPUNOV exponent distributions obtained by moving a window of increasing size over bootstrapped same-length estimates of an observation function, a dispersion measure's width is calculated and fed into a BAYESIAN beta-binomial model. Results obtained using this method for benchmark models of white and pink noise as well as the classical HENON map indicate that true LYAPUNOV exponents can be isolated from spurious ones with high confidence. The method is then applied to accelerometer and microphone data obtained from brake squeal tests. Estimated LYAPUNOV exponents indicate that the pad's out-of-plane vibration behaves quasi-periodically on the brink to chaos while the microphone's squeal signal remains periodic.

  6. A method to achieve comparable thermal states of car brakes during braking on the road and on a high-speed roll-stand

    Science.gov (United States)

    Wolff, Andrzej

    2010-01-01

    The temperature of a brake friction surface influences significantly the braking effectiveness. The paper describes a heat transfer process in car brakes. Using a developed program of finite element method, the temperature distributions in brake rotors (disc and drum brake) of a light truck have been calculated. As a preliminary consistency criterion of the brake thermal state in road and roll-stand braking conditions, a balance of the energy cumulated in the brake rotor has been taken into account. As the most reliable consistency criterion an equality of average temperatures of the friction surface has been assumed. The presented method allows to achieve on a roll-stand the analogical thermal states of automotive brakes, which are observed during braking in road conditions. Basing on this method, it is possible to calculate the braking time and force for a high-speed roll-stand. In contrast to the previous papers of the author, new calculation results have been presented.

  7. Low braking index of PSR J1734-3333: an interaction between fall-back disc and magnetic field?

    Science.gov (United States)

    Chen, Wen-Cong; Li, Xiang-Dong

    2016-01-01

    Recent timing observation reported that the radio pulsar PSR J1734-3333 with a rotating period P = 1.17 s is slowing down with a period derivative dot{P}=2.28× 10^{-12} s s^{-1}. Its derived braking index n = 0.9 ± 0.2 is the lowest value among young radio pulsars with the measured braking indices. In this Letter, we attempt to investigate the influence of the braking torque caused by the interaction between the fall-back disc and the strong magnetic field of the pulsar on the spin evolution of PSR J1734-3333. Analytical result show that this braking torque is obviously far more than that by magnetic dipole radiation for pulsars with spin period of >0.1 s, and play an important role during the spin-down of the pulsars. Our simulated results indicate that, for some typical neutron star parameters, the braking index and the period derivative approximately in agreement with the measured value of PSR J1734-3333 if the material inflow rate in the fall-back disc is 2 × 1017 g s- 1. In addition, our scenario can account for the measured braking indices of four young pulsars. However, our predicted X-ray luminosity are one to two order of magnitude higher than the observation. We proposed that this discrepancy may originate from the instability of fall-back disc.

  8. Influence of Optimizing Brake Pads Structure on Brake Disc Temperature and Thermal Stress%优化结构闸片对制动盘温度及热应力的影响

    Institute of Scientific and Technical Information of China (English)

    农万华; 符蓉; 韩晓明

    2012-01-01

    为了研究列车制动产生摩擦热对制动盘的耐热疲劳性能的影响,分析了摩擦热流分布与闸片结构的关系,提出一种优化闸片摩擦块固定位置,达到改善制动盘摩擦热分布的方法,采用有限元软件ABAQUS对优化前后的闸片制动过程进行了数值模拟,结果表明:与闸片优化前相比,闸片优化后制动盘最高温度和热应力分别下降的17%和23%,沿制动盘径向分布更均匀.%In order to study the effects of friction heat generation on thermal fatigue performance of brake disc during train braking, the relationship between friction heat flux distribution and brake pad structure was discussed , and a method of optimizing the brake pad friction blocks to improve the distribution of friction heat on brake disc was proposed. By finite element software ABAQUS, the braking process using the optimized brake pads and non-optimized brake pads was simulated respectively. The results show that the temperature of the optimized brake disc brake pads are decreased and the radial distribution of the thermal stress is more uniform along the brake disc. The results show thai compared with the brake pads before optimization, the highest temperature and thermal stress of the optimized brake discs brake pads are decreased by 17% and 23% respectively.

  9. Preparation and characteristics of C/C composite brake disc by multi-cylindrical chemical vapor deposition processes

    Institute of Scientific and Technical Information of China (English)

    YUAN Yi-dong; ZHANG Fu-kuan; ZHOU Wan-cheng

    2005-01-01

    The C/C composite brake discs were prepared by tri-cylindrical chemical vapor deposition (CVD) process. The optimum processing parameters were as follows: deposition temperature was 830-930 ℃, the gas-flow rates of N2 and propylene were 4.8-5.2 m3/h and 5.8-6.2 m3/h, respectively, the furnace pressure was 4.5-5.5 kPa and the deposition time was 200 h.The effects of processing parameters on the densified rates, thermal-physical property and mechanical performance of C/C composite brake discs were studied. The results show that density, heat conductivity, bend strength and abrasion ratio of the multi-cylindrica brake discs are 1.02-1.78 g/cm3, 31 W/(m·K), 114 MPa and 7 μm/s, respectively, which are approximately similar to those of the single-cylindrical ones. The gas flow rate has no relation to the number of the cylinder and furnace loading. The utilization ratio of carbon can be improved by multi-cylinder CVD process without changing the characteristics of brake disc.

  10. 修井机盘式制动器模态分析%Mode Analysis of Disc Brakes in Workover Rig

    Institute of Scientific and Technical Information of China (English)

    李连峰; 高栋梁; 隋秀伟; 喇红云; 康文彬

    2011-01-01

    阐述了修井机盘式制动器的制动原理,通过对其有限元模型的简化,对制动盘制动时可能出现的抖动情况进行模态分析,并提出相应的改进措施,避免机构在实际过程中发生共振.%The Workover disc brake braking principle is described, using its finite element model of simplified, brake disc braking possible jitter analysis for mode, and appropriate measures to avoid bodies in the actual process of resonance is proposed.

  11. 弹性盘型制动闸片装置振动特性研究%On Vibration Characteristics of Elastic Disc Brake Pad Device

    Institute of Scientific and Technical Information of China (English)

    杨宽; 张济民

    2013-01-01

    设计了一种新型的具有弹性的盘型制动闸片装置,建立了低速的轨道车辆弹性盘型制动的数学模型,与无弹性的制动闸片进行了单轴制动特性的动态仿真比较.仿真结果表明,具有弹性的闸片制动时同样能够保证车辆的制动性能;在制动盘或闸片摩擦面有缺陷时,弹性闸片能有效降低闸片与制动盘间摩擦力引起的振动.该设计为盘型制动系统的设计及分析提供了新的思路.%A new elastic disc brake pad device is designed, and a mathematical model on low speed railway vehicle e-lastic disc brake is established to compare with the non-elastic brake pad by single wheel-set braking simulation. The result shows that the elastic brake pad can guarantee the vehicle braking performance as same as the non-elastic brake pad. When the disc or the friction surface of brake pad has some defects, elastic brake pad can effectively reduce the friction and the vibration between the brake pad and the brake disc. The design has been proved to be correct and rational, it will provide new ideas for the design and analysis of the disc brake system.

  12. Designs on Electric Control Processes of Automotive Electric Parking Brake System%汽车电子驻车制动EPB系统电控流程设计

    Institute of Scientific and Technical Information of China (English)

    刘峰

    2016-01-01

    The author introduces the designs on the control principles and processes of automotive EPB electrical control system, including brake process, brake release process, ramp start process, emergency brake process and in-telligent brake process, in order to provide a reference for the application of the electronic parking brake system.%介绍汽车EPB电控系统原理与电控流程设计,包括制动流程、解除制动流程、坡道起步流程、紧急制动流程、智能制动流程等,为电子驻车制动系统的应用提供参考。

  13. 基于 ANSYS的制动盘模态分析%Brake Disc Mo dal An alysis Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    汉世成

    2014-01-01

    Brake disc is the key component of disc brake, which vibration during braking has a greater impact on its perform-ance.In order to accurately grasp the vibration performance characteristics, the finite element model of brake disc is estab-lished by finite element method, and its freedom and constraint modal analysis are studied.The results get in the front of six natural frequencies and mode shapes of brake disc, and the weak modal of brake disc is identified and provide a theoretical reference for material selection and design of the brake disc.%制动盘作为盘式制动器的关键部件,在制动过程中发生的振动对其工作性能有较大的影响,为了准确把握其振动性能特性,采用有限元方法建立制动盘部件有限元模型,并对其进行自由模态分析和约束模态分析,研究得到了制动盘前六阶固有频率和振型,并确定了制动盘的薄弱模态,研究结果为制动盘的选材和设计提供了一定的理论参考。

  14. Engineering wear-resistant surfaces in automotive aluminum

    Science.gov (United States)

    Kavorkijan, V.

    2003-02-01

    Inadequate wear resistance and low seizure loads prevent the direct use of aluminum alloys in automotive parts subject to intensive friction combined with high thermal and mechanical loading, such as brake discs, pistons, and cylinder liners. To enable the use of aluminum alloys in the production of automotive brake discs and other wear-resistant products, the insertion of a monolithic friction cladding rather than surface coating has been considered in this work. Three experimental approaches, two based on the pressure-less infiltration of porous ceramic preforms and one based on the subsequent hot rolling of aluminum and metal-matrix composite strips, are currently under investigation.

  15. Simulation and Experimental Analysis of Braking Squeal of Disc Brake System Considering Thermo-mechanical Coupling Effect%盘式制动器制动尖叫热机耦合特性仿真分析

    Institute of Scientific and Technical Information of China (English)

    汪德成; 陈凌珊; 黄欣; 蒋培露

    2014-01-01

    利用试验和仿真相结合的方法,对某车型前通风盘式制动器进行研究。基于多功能制动器动力学试验台架,分别对两套同型号制动器试件进行制动尖叫试验,基于有限元建立制动器热机耦合分析模型,在拖滞制动模式下进行仿真计算。分析研究表明,拖滞制动模式是一个明显的热机耦合过程,其热机耦合效应与减速制动模式具有很多共同点。热机耦合效应对制动尖叫影响较大,考虑热机耦合效应有利于提高尖叫预测精度,并能够反映制动尖叫的时变特性。%Braking squeal of ventilation disc brake systems was studied through experimental and numerical analysis. Using multi-function brake dynamometer test rig, brake squeal tests of two disc brake systems were carried out. The finite element model of the disc brake was built, and the thermo-mechanical coupling effect was investigated under drag braking conditions. The simulation results show that the thermo-mechanical coupling effect exists obviously in drag braking mode, which is similar to that in emergency braking mode. This effect has a serious influence on braking squeal. It must be considered in the brake squeal simulation analysis to improve the prediction accuracy and to reflect the time-varying characteristics of the braking squeal.

  16. Reduction of Noise from Disc Brake Systems Using Composite Friction Materials Containing Thermoplastic Elastomers (TPEs)

    Science.gov (United States)

    Masoomi, Mohsen; Katbab, Ali Asghar; Nazockdast, Hossein

    2006-09-01

    Attempts have been made for the first time to prepare a friction material with the characteristic of thermal sensitive modulus, by the inclusion of thermoplastic elastomers (TPE) as viscoelastic polymeric materials into the formulation in order to the increase the damping behavior of the cured friction material. Styrene butadiene styrene (SBS), styrene ethylene butylene styrene (SEBS) and nitrile rubber/polyvinyl chloride (NBR/PVC) blend system were used as TPE materials. In order to evaluate the viscoelastic parameters such as loss factor (tan δ) and storage modulus (E‧) for the friction material, dynamic mechanical analyzer (DMA) were used. Natural frequencies and mode shapes of friction material and brake disc were determined by modal analysis. However, NBR/PVC and SEBS were found to be much more effective in damping behavior. The results from this comparative study suggest that the damping characteristics of commercial friction materials can be strongly affected by the TPE ingredients. This investigation also confirmed that the specimens with high TPE content had low noise propensity.

  17. 汽车真空辅助制动系统的设计与研究%Design and Research of Automotive Vacuum Auxiliary Braking System

    Institute of Scientific and Technical Information of China (English)

    刘树伟; 郭立新; 郝亮

    2015-01-01

    以汽车紧急制动工况为研究对象,设计和研制了一种汽车真空辅助制动系统,该系统主要包括机械执行机构、制动吸盘、真空系统、弹射收起系统、控制系统五个部分。对该系统进行了理论分析和实验研究,结果表明,该系统可显著提高汽车制动效能,可有效缩短汽车紧急制动时的制动距离,从而有效降低交通事故的发生概率并降低交通事故的严重程度。%An automotive vacuum auxiliary braking system was designed when the driver urgently braked the automobile.The system mainly contained five parts,such as mechanical actuator,braking sucker,vacuum system,ejection retracting system,the control system and so on.The vacuum auxiliary braking system could increase significantly the braking efficiency and shorten the braking distance of automobile emergency braking.After the theoretical analysis and the experimental research,the sys-tem will reduce effectively the probability and the damage degree of traffic accidents.

  18. The Development of a Fuzzy Predictive Control System for Automotive Anti-lock Braking System

    Institute of Scientific and Technical Information of China (English)

    HUANGFU Shihui; BAO Xiangying

    2006-01-01

    This paper presents the model of one-tire kinetics、tires、the braking system and the model of control system. On virtual road, this paper builds a fuzzy predictive control system to insure the best attachment coefficient between tires and road. And it turns out to be that this fuzzy predictive control method has achieved good performances.

  19. 制动盘材料选型仿真对比分析%Simulation Comparative Analysis of Brake Disc Material Selection

    Institute of Scientific and Technical Information of China (English)

    金文伟; 廉超; 钱坤才; 王常川

    2013-01-01

      针对高速动车组运行速度高,制动释放能量大,对基础制动装置特别是制动盘高温性能要求高等特点,研究了新型合金钢材料和结构制动盘。通过运用ANSYS仿真软件对1#材料和2#材料两种制动盘盘体的温度场、热应力场等关键性能进行仿真对比分析,结果表明:2#材料制动盘的温升、盘体热应力情况明显优于1#材料制动盘,为高速列车制动盘的材料选择提供了依据。%In view of the characteristics of High Speed Train-high speed, large braking energy releasing, high requirements for foundation braking device especially for braking disc high temperature performance, this paper studies the new alloy steel material and structure brake disc. The ANSYS simulation software is used to do simulation comparative analysis of the disc temperature field, thermal stress field and other key performance of 1#material and 2#material brake disc. The result shows that, the temperature rise and disc thermal stress of 2# material brake disc is much better than that of 1#material and thus providing basis for the material selection of high speed train brake disc.

  20. Finite Element Analysis on the Brake Noise of Disc Brake Based on NASTRAN%基于Nastran盘式制动器制动噪声的有限元分析

    Institute of Scientific and Technical Information of China (English)

    方韶华; 方永寿

    2015-01-01

    为降低盘式制动器制动尖叫噪声,应用制动盘和摩擦片的耦合模型直接复特征值分析方法研究制动器的运动状态,采用Nastran有限元软件建立制动盘和摩擦片的有限元模型,用线性弹簧力来表示制动摩擦面间的法向力,其中线性弹簧力与摩擦因数的乘积就是制动摩擦力;通过解特征方程得到特征根,并根据特征根实部的正负判断制动器发生制动尖叫噪声的趋势。结果显示,盘片间的摩擦不规则是制动器噪声产生重要因素,认为制动器噪声可以通过降低制动器盘片间的摩擦因数来抑制。%In order to suppress the brake noise of disc brake, motion stability of disc brake is studied using a direct complex eigenvalue analysis technique of coupled model of the disc and the pads. Finite element software NASTRAN is applied to establish finite element model of disc brake including one disc and two pads.In the model, the normal force at the contact interface is shown with linear spring force. The friction force is taken as the product of linear spring force and friction coefficient. Numerical simulation result shows that the friction coefficient of the disc and the pads have significant influence on the occurrence of brake noise. Brake noise can be suppressed by reducing the friction coefficient.

  1. ANALYTICAL COMPARISION OF DISC BRAKES WITH LINEAR AND CURVED SHAPED SLOTS BETWEEN PLATES FOR STRUCTURAL ANALYSIS ON DIFFERENT PARAMETER USING THROUGH CATIA V5 R20 AND ANSYS 15.0.7

    OpenAIRE

    Vivek Kumar*, Anshuka Srivastava

    2016-01-01

    The process which converts the kinetic energy of the vehicle into mechanical energy is known as Braking, which must be dissipated in the form of heat. The device using for decelerating or stopping the rotation of a wheel is called as disc brake. A brake disc (or rotor) usually made of linear shaped slots between plates and a disc brake ( or rotor) usually made of curved shaped slots between plates having materials used in both is Structural Steel, is connected to the wheel and/or the axle. Fr...

  2. FSAE 纯电动方程式赛车制动盘发热研究%Study of Thermal about Braking Discs of FSAE Electric Racing Car

    Institute of Scientific and Technical Information of China (English)

    韩小强; 高天涵; 蒋迪; 郭炯珉

    2016-01-01

    基于大学生方程式赛车比赛的特点,该文根据制动原理与传热理论,使用理论分析法分别研究了赛车在紧急制动和持续制动两种工况中制动盘的温度情况,判定是否会因为温度过高而发生热衰退等失效。通过 COMSOL Multiphysics 的固体传热模块对赛车的紧急制动与持续制动进行仿真分析,得出在紧急制动以及持久制动后制动盘的温度,从而对理论计算进行验证,为制动盘的优化设计提供了理论依据。%It is important to study the thermal of the braking disc when having the FSAE competition.In this paper,the heat of the braking discs is studied during the process of emergency braking and continuous braking by the theory of heat transfer and the theory of braking in order to estimate whether the temperature of disc is extremely hot and have failure or not.After that,heat transfer in solid’s modular of Comsol Multiphysics is used to have thermal analysis about the racing car’s emergency braking condition and continuous bra-king condition,then have the temperature of the disc after emergency condition and duration condition.Finally,we validate theoretical calculation and provide theoretical basis for optimal design of disks.

  3. An evaluation of short-term exposures of brake mechanics to asbestos during automotive and truck brake cleaning and machining activities.

    Science.gov (United States)

    Richter, Richard O; Finley, Brent L; Paustenbach, Dennis J; Williams, Pamela R D; Sheehan, Patrick J

    2009-07-01

    Historically, the greatest contributions to airborne asbestos concentrations during brake repair work were likely due to specific, short-duration, dust-generating activities. In this paper, the available short-term asbestos air sampling data for mechanics collected during the cleaning and machining of vehicle brakes are evaluated to determine their impact on both short-term and daily exposures. The high degree of variability and lack of transparency for most of the short-term samples limit their use in reconstructing past asbestos exposures for brake mechanics. However, the data are useful in evaluating how reducing short-term, dust-generating activities reduced long-term exposures, especially for auto brake mechanics. Using the short-term dose data for grinding brake linings from these same studies, in combination with existing time-weighted average (TWA) data collected in decades after grinding was commonplace in rebuilding brake shoes, an average 8-h TWA of approximately 0.10 f/cc was estimated for auto brake mechanics that performed arc grinding of linings during automobile brake repair (in the 1960s or earlier). In the 1970s and early 1980s, a decline in machining activities led to a decrease in the 8-h TWA to approximately 0.063 f/cc. Improved cleaning methods in the late 1980s further reduced the 8-h TWA for most brake mechanics to about 0.0021 f/cc. It is noteworthy that when compared with the original OSHA excursion level, only 15 of the more than 300 short-term concentrations for brake mechanics measured during the 1970s and 1980s possibly exceeded the standard. Considering exposure duration, none of the short-term exposures were above the current OSHA excursion level.

  4. Thermal Field Analysis of Automobile Brake Disc Based on ANSYS%基于ANSYS的汽车制动盘温度场仿真分析

    Institute of Scientific and Technical Information of China (English)

    赵文杰; 吴涛; 徐延海; 孙泽海

    2012-01-01

    以热分析理论为基础,使用有限元软件ANSYS建立乘用车普遍使用的通风式制动盘模型.在此基础上,模拟分析了紧急制动和持续制动工况下制动盘的瞬态温度场分布,得到了制动盘外部及其内部散热筋板的温度场、温度变化分布以及内外温度梯度的变化,为制动器的设计提供了较好的理论基础,也为判断制动器是否失效提供了依据.%In this paper, the finite element model for ventilated brake disc is developed based on the theory of finite element meth-od by using the modeling capability of finite element software ANSYS. From the simulation analysis of the emergency braking and the continued braking condition, the transient temperature field distribution, temperature distribution and temperature gradient in the external and internal cooling ribs of the brake disc are obtained. The numerical results can give some theoretical basis and judgment for the design and failure of the brake disc.

  5. 基于ANSYS的制动盘瞬态热仿真分析%Simulated Transient Thermal Analysis on Brake Disc Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    杨仁华

    2015-01-01

    本文运用ANSYS技术对汽车制动器制动盘进行了急速制动温度分布仿真分析.分析了100Km/h情况下汽车紧急、连续制动工况,利用Solidworks三维软件对制动盘进行实体建模,并导入到ANSYS,利用ANSYS进行仿真分析,得出温度在周向及径向的分布情况.%In this paper, ANSYS technology was used to simulate the temperaturedistribution of brake disc. The emergent and continuous braking conditions were analyzedunder the speed of 100Km/h. Solidworks 3D software was used to simulate the brake disc, and ANSYS was used to simulate the distribution of temperature in the circumferential and radial direction.

  6. Bamboo Fibre-reinforced Semi-Metallic Brake Friction Materials for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Talib R. J.

    2016-01-01

    Full Text Available Three friction material formulations composed of bamboo fiber along with binder, friction modifiers and filler have been prepared through powder metallurgy process. Sample F1 and F2 are composed of 10 wt. % of copper and barium, respectively, while the other ingredients in both formulations have the same wt. %. The wt. % of bamboo fiber in sample F3 is, however, increased by 100%, while the compositions of the other ingredients are proportionally decreased. The samples were examined for their porosity, hardness, and friction and wear properties using hot bath, Rockwell hardness tester, and CHASE friction dynamometer, respectively. The test results are compared with those of a commercial sample as the benchmark. Normal and hot frictions of all the three samples developed comply with the requirements specified by Automotive Manufacturer Equipment Companies Agency (AMECA. However, sample F3 which is composed of 20 wt. % of bamboo fiber does not comply with the minimum requirement of friction coefficient. Whereas, sample F2, which is composed of 10 wt. % of bamboo fiber and 10 wt. % of barium, has lower friction coefficient than the commercial sample, and has a sudden drop in friction coefficient at a temperature of 500°F. Out of three developed samples, sample F1, which is composed of 10 wt. % of bamboo fiber and 10 wt. % of copper, complies with all the requirements and has higher friction coefficient than the commercial sample, and has higher fade resistance. Thus, it could be postulated that bamboo fiber could be used as a reinforcing fiber with composition of 10 wt. %.

  7. Simulation of the Friction Temperature Field for Disc Brake%盘式制动器摩擦温度场的数值模拟

    Institute of Scientific and Technical Information of China (English)

    刘莹; 周启兴

    2012-01-01

    采用COMSOL Multiphysics模拟盘式制动器制动过程的二维瞬态温度场,研究了割动盘和摩擦片的温度分布情况以及它们的热物性参数对摩擦副温度场的影响.结果表明:盘式制动器在制动过程中的高温时刻,高温处在沿盘转动方向与摩擦片滑出的区域;制动盘表面温度从高温度区域沿制动盘转动方向递减,摩擦片表面温度沿盘转动反方向递减;制动盘和摩擦片的径向温度最大值出现在摩擦区域的中部位置,而外径和内径处温度较低,轴向方向都由摩擦面表层向内层方向递减;增大制动盘或摩擦片的某一热物性参数均可降低摩擦副表面最大温度值,但制动盘相对摩擦片,其导热系数、比热容和密度对摩擦副温度值的影响要大得多,研究内容可为制动器的结构设计及材料的选择提供参考.%The three-dimensional transient temperature field for disc brake were simulated using software COM-SOL Multiphysics, the situation of temperature distribution for friction pairs device in the braking process and the effect of material thermal parameters on its temperature field were investigated. The results showed that at the high-temperature moment of the braking process of the disc brake, the high temperature place was located on the area of sliding out with the friction plate along the disk rotates direction; the surface temperature of brake disc decreased from the high temperature zone along the direction of the brake disc rotation; the surface temperature of friction plate decreased along the opposite direction of the brake disc rotation; the maximum radial temperature of the brake disc and friction plate in the braking process was located on the central part of the friction zone,the temperature of the outside radius and inside radius was lower, the temperature of the axial direction decreased from the friction surface layer to the inner layer direction; it can reduce the maximum

  8. 盘式制动器振动特性的研究%Study on vibratory characteristics of disc brakes

    Institute of Scientific and Technical Information of China (English)

    王和伟; 伍洪云; 王道明; 张楠

    2011-01-01

    利用有限元分析软件时盘式制动器的主要零件进行了模态分析,得到了各阶振型和频率.进而分析了发生共振的可能性,提出了改进方案,并结合模态试验的方法验证了仿真分析的准确性,对生产实践具有一定的指导意义.%Modal analysis of some main components of disc brakes are carried out with finite element analysis software, and the natural frequency and the vibration mode of each order are obtained.In addition, the possibility of resonance is analysed and the improvement scheme is proposed.At last, the simulation accuracy is verified by modal tests.The study has some guidance significance for practical productions.

  9. 基于ABAQUS的列车盘型制动的温度场分析%Analysis on Temperature Field of Train Disc Brake Based on ABAQUS

    Institute of Scientific and Technical Information of China (English)

    王国顺

    2013-01-01

    The influences of rotating speed and the friction radius,height and shape,and place form of braking block on the temperature field of the brake disc and brake block were simulated by the finite element analysis software of ABAQUS.The results show that with the increase of crank's rotating speed,the brake disc and brake block's temperatures are increased,and the distribution of high temperature region is changed from stripe to speckle.The reason is that with the increase of revolving speed,the vibration between the friction pairs is aggravated,and the local contact was produced to cause the high temperature.There is an inflection point of temperature in the thickness direction of brake disc,with the increase of the distance to the friction surface,the temperature is declined rapidly,and in the distance of 3 ~ 6 mm to the friction surface,the change of temperature is not obvious.The change of brake block height or shape has no obvious influence on the brake disc temperature,while the placement form of the triangle brake block has influence on temperature distribution.%应用有限元软件ABAQUS,模拟转动速度和制动块摩擦半径、高度以及形状与放置形式等对制动盘和制动块温度场的影响.得出如下结论:随转速的提高,制动盘和制动块温度升高,高温区的分布由条带状向斑点状转变,原因在于随转速增加,摩擦副间的振动程度加剧,从而造成局部接触产生高温.制动盘温度在厚度方向上存在一个拐点,随深度增加,制动盘温度快速下降,在距摩擦表面3~6mm时,温度变化不明显.制动块高度、形状改变,对制动盘温度无明显影响,而三角形制动块的放置形式对制动块温度分布有影响.

  10. Numerical simulation and experimental study for the die forging process of a high-speed railway brake disc hub

    Science.gov (United States)

    Sun, Mingyue; Xu, Bin; Zhang, Long; LI, Dianzhong

    2013-05-01

    With the aim of manufacturing a near-net shape forging product of a brake disk hub for the high-speed railway, the die forging process was designed and optimized in this study. Firstly, based on the measured stress-strain curves at different strain rates and the thermal-physical parameters of 40Cr A steel, a finite element model for the forging process of a high-speed railway brake disc hub was established. Then, the temperature, stress and strain fields were studied and analyzed at the pre-forging and the finial-forging stages. Besides, in order to trace the stress and strain evolution, five points at different positions were chosen on the billet, and the comparison of the state conditions was made among these points. The results have demonstrated that the product can be well formed by an elaborately designed three-stage forging process, which may reduce the metal machine allowance and the producing cost effectively. Finally, an industrial trial was made and a machined product with sound quality was obtained.

  11. 基于移动热源的盘式制动器三维瞬态温度场仿真分析%Simulation of Three-dimensional Transient Temperature Field for Disc Brake Based on Moving Heat Source

    Institute of Scientific and Technical Information of China (English)

    张建辉; 张兵; 闫先朝

    2015-01-01

    Taking FSAE car front disc brake as a research subject, the effect of moving heat source on the disc brake was analyzed, the model of three-dimensional transient temperature field for the brake was established by using Ansys. The temperature distribution of brake disc and the time course curve of different nodes in an emergency braking condition were gained.%以FSAE赛车前轮盘式制动器为研究对象,考虑了移动热源的影响,运用Ansys软件建立了其三维瞬态温度场模型。由此得到了一次紧急制动工况,不同初始车速制动盘的温度场分布以及其上不同位置节点温度的时间历程曲线。

  12. 浅述气压盘式制动器在城市客车上应用的可能性与可行性%Possibility and feasibility of air pressure disc brake applicated in city bus

    Institute of Scientific and Technical Information of China (English)

    孙吉宝; 温述波

    2012-01-01

    Analyse the possiblity and feasibility of air pressure disc brake applicated in city bus,focus on discussing the development of 5.5t disc brake front axle,and calculate the brake moment of disc brake front axle and drum brake front axle.%分析了气压盘式制动器在城市客车上应用的可能性与可行性,重点论述了5.5T盘式制动器前桥的开发,并对盘式制动器前桥与鼓式制动器前桥的制动力矩进行对比计算。

  13. 汽车EPB系统控制原理研究%Researches on Control Principles of Automotive Electric Parking Brake EPB System

    Institute of Scientific and Technical Information of China (English)

    刘峰

    2016-01-01

    汽车电子技术的不断进步,令驻车制动系统即手制动系统从过去机/液式的,逐渐变成电子式的。电子驻车制动可在行车前自动释放或在熄火后自动拉紧,省去了忘记解除驻车制动或“坡起”溜车等情况的困扰与风险;由于电子驻车制动系统即EPB系统的结构较为复杂,需要对其控制原理进行分析研究,本文主要包括EPB的组成及工作原理等。%With the automobile’s and electrical technology constantly development, the parking brake system is changing from the primary mechanical, hydraulic into electrical. Electric parking brake (EPB) system is able to release it before ignoring or strain it after stopping the engine automatically, and cuts the dififculties and dangerous rates of forgetting to be released or the slide on the slope; Because of the automotive EPB frame is so complex, the electrical brake system needs to analysis. This thesis is mainly contains the EPB structures and working principles.

  14. Analysis of natural frequency variability of a brake component

    Science.gov (United States)

    Gallina, A.; Lisowski, W.; Pichler, L.; Stachowski, A.; Uhl, T.

    2012-10-01

    The manufacture of automotive disc brake calipers is subjected to many inherent variabilities resulting in product variability. In particular, the dispersion of natural frequency values is a primary issue in the context of vehicle comfort. This paper aims to quantify natural frequency variability and search for its causes. Extensive experimental tests and numerical simulations, described in the paper, point out the fundamental role of mold wear and assembling process in this variability.

  15. 汽车盘式片热压成型方式的对比分析%Comparative Analysis of Automotive Brake Pads Thermoforming

    Institute of Scientific and Technical Information of China (English)

    李云鹏; 宫宝利; 杜宝程; 王铁山

    2013-01-01

    Three forming methods and press forming equipment of automotive disc pad in China are introduced in this paper, and test and analysis are made to the product made by those three forming methods. The results show that the density and compression ratio of the automotive disc pads formed with single-cylinder single chamber geometric pressure are superior to those made with other two forming methods, structural characteristics of a new type of disc pad developed based on specific pressure principle is introduced in the paper.%介绍了我国现有汽车盘式制动片的3种成型方式和压制成型设备,并针对这3种成型方式压制成型的产品进行了测试分析.结果表明,采用单缸单腔等比压压制方式成型的汽车盘式制动片,其密度和压缩率均优于另2种压制方式成型的产品.介绍了一种基于等比压原理研制的新型盘式制动片的结构特点.

  16. A Reduced-Order Model for Complex Modes of Brake Squeal Model and Its Application to a Flexible Pin-on-Disc System

    Directory of Open Access Journals (Sweden)

    Lijun Zhang

    2015-01-01

    Full Text Available Brake squeal is often analytically studied by a complex eigenvalue analysis of linearized models of the brake assembly that is usually quite large. In this paper, a method for determining those frequencies having the most effect on the pair of coupling frequencies that saves much time is put forward and a reduced-order model is presented based on the complex modes theory. The reduced-order model is proved to be effective when applied to a flexible pin-on-disc system; even damping and nonlinearity are taken into consideration. This reduced-order model can predict the onset of squeal as well as the squeal frequency with sufficient accuracy and largely reduced amount of calculation and gives us a practical guide to perform design optimization in order to reduce brake squeal.

  17. 盘式制动器关键零部件模态分析%Modal Analysis of the Key Parts in a Disc Brake

    Institute of Scientific and Technical Information of China (English)

    郑刚; 谢方伟; 王和伟; 王书蒙

    2013-01-01

    盘式制动器是一种常用的制动装置,多用于汽车和其他运输设备在工作过程中盘式制动器发生的各种振动对其工作性能有较大的影响,为了准确把握其振动特性,采用ANSYS软件建立盘式制动器零部件三维有限元模型,并进行约束模态分析,研究得到了关键零部件(摩擦盘和卡钳)的前六阶固有频率和振型,结果表明摩擦盘的第三阶固有频率和卡钳的第二阶固有频率较接近,可能引起系统的共振;研究结果为盘式制动器的优化设计提供了一定的理论参考.%Disc brake is a common brake apparatus, which is used in car and other transporting equipment. The vibration has great influence on the performance of the disc brake in the working process. In order to accurately grasp its vibration characteristics, a three -dimensional finite element model of brake parts were established using ANSYS software and a constraint modal analysis was made. The first six order natural frequency and vibration model of disk and caliper were obtained. The results showed that the third order natural frequency of the friction disk and the second order natural frequency of the caliper is very close, which may cause resonance of the system. The research results provide certain theoretical reference for the optimization design of the disc brake.

  18. 基于ANSYS的汽车盘式制动器总成分析%Finite Element Analysis of Automobile Disc Brake Assembly based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    郑荣; 黄伟中; 徐飞军; 邱晓久; 刘禄芳

    2012-01-01

    运用有限元软件ANSYS对某型号轿车盘式制动器总成进行有限元分析,获得了在四种不同工况下,导向销和定位销的应力应变云图.仿真结果表明制动器的钳体、支架、导向销和定位销满足强度要求,证明盘式制动器的设计是合理的.%The finite element analysis of the some automobile disc brake assembly is carried out by using the software ANSYS. Under the four working conditions,stress and strain cloud of guide and locating pins are obtained. Results of the simulation show that the caliper.lhe bracket and pins satisfy design strength requirements and design of the disc brake is successful.

  19. 基于ADAMS的电力液压盘式制动器仿真研究%Simulation of Electro-hydraulic Disc Brake Based on ADAMS

    Institute of Scientific and Technical Information of China (English)

    姜朝俊; 田树涛; 孔祥虎

    2015-01-01

    以电力液压盘式制动器为研究对象 ,利用ADAMS软件进行建模仿真 ,优化分析获得制动器所需要的制动力矩和间隙.仿真数据与试验数据对比表明 :ADAMS软件的分析结果和试验数据基本吻合 ,为制动器的设计和计算提供了可靠的方法和依据 ,节省了研发费用并缩短了开发周期.%Taking an electro-hydraulic disc brake as research object ,this paper carried out the simulation analysis on electro-hydraulic disc brake ,getting braking moment and clearance .Experimental data show the analytical results of ADAMS agree with that of ex-perimental data .It provides a reliable method and basis for the design of brakes .

  20. Squeal noise in simple numerical brake models

    Science.gov (United States)

    Oberst, S.; Lai, J. C. S.

    2015-09-01

    Since the early 1920s, automotive disc brake squeal has caused warranty issues and customer dissatisfaction. Despite a good deal of progress achieved, predicting brake squeal propensity is as difficult as ever as not all mechanisms and interactions are known owing to their highly fugitive complex nature. In recent years, research has been focused on the prediction of unstable vibration modes by the complex eigenvalue analysis (CEA) for the mode-coupling type of instability. There has been very limited consideration given to the calculation of the acoustic radiation properties due to friction contact between a pad and a rotor. Recent analyses using a forced response analysis with harmonic contact pressure excitation indicates negative dissipated energy at some pad eigenfrequencies predicted to be stable by the CEA. A transient nonlinear time domain analysis with no external excitation indicates that squeal could develop at these eigenfrequencies. Here, the acoustic radiation characteristics of those pad modes are determined by analysing the acoustic power levels and radiation efficiencies of simplified brake models in the form of a pad rubbing on a plate or on a disc using the acoustic boundary element method based on velocities extracted from the forced response analysis. Results show that unstable pad modes trigger unstable disc vibrations resulting in instantaneous mode squeal similar to those observed experimentally. Changes in the radiation efficiency with pressure variations are smaller than those with friction coefficient variations and are caused by the phase difference of the velocities out-of-plane vibration between the pad and the disc.

  1. 高速列车制动盘泵风效应分析%Air-pumping effect analysis for brake disc of high-speed train

    Institute of Scientific and Technical Information of China (English)

    左建勇; 罗卓军

    2014-01-01

    To study the air-pumping characteristics of brake disc during train operation,the finite element models including vehicle,rail,brake disc and related air flow field were put forward. The air-pumping power consumption of brake disc was calculated,and its effect on traction power was analyzed by using dynamic grid and flow-solid conjugation simulation method.Taking a 8-unit high-speed train composed of 4 motor cars and 4 trailers running at 300 km · h-1 as an example,the air-pumping effect of brake disc was simulated and compared.Simulation result indicates that the air-pumping power consumption of brake disc is in proportion to train running speed.The air-pumping power consumption of each car is about 54-70 kW.The air-pumping torque,independent of installation position of brake disc,is mainly influenced by the rotational velocity of brake disc.The proportion of air-pumping power consumption of brake disc reduces with the increase of train running velocity.When train running velocity increases from 200 km·h-1 to 400 km·h-1 ,the proportion of air-pumping power consumption reduces from 12% to 8%. Blocking air from the inlets of brake discs is helpful to reduce the influence of air-pumping power consumption.Taking the train running at 300 km·h-1 as an example,when the inlets of brake discs are blocked,the air-pumping power consumption of brake disc reduces from 489 kW to 68 kW,the basic resistance power consumption consumed by air-pumping power consumption reduces from 9. 0% to 1. 3%,so the method is effective.Obviously,it has greater realistic meanings for the cooling rib structure optimization of brake disc of high-speed train in considering the air-pumping power consumption issue.2 tabs,10 figs,15 refs.%为研究列车运行过程中制动盘泵风特性,建立了列车、轨道、制动盘及其附近空气流场的有限元模型,采用动网格流固耦合仿真方法,计算了制动盘泵风功耗,分析了制动盘泵风对牵引功率的

  2. MW级风力发电机组偏航制动盘强度分析%Strength Analysis for MW Wind Turbine Yaw Brake Disc

    Institute of Scientific and Technical Information of China (English)

    何海建; 苏凤宇; 董姝言; 齐涛; 晁贯良

    2016-01-01

    偏航制动盘是风力发电机组中受力情况较为复杂、可靠性要求较高的关键部件之一,其强度直接关系到整个机组的安全运行。基于GL规范,采用有限元方法对偏航制动盘进行静强度和疲劳强度分析,并且给出了偏航制动盘部件S N曲线的详细拟合过程,有效解决了偏航制动盘强度计算问题,为风机的安全运行提供了可靠的技术支持。%The yaw brake disc is one of the key components of wind turbines that are always bearing complex loads with a severer requirement for reliability.Its strength directly impacts the operation of whole wind turbine.In this article,the ultimate and fatigue strength of yaw brake disc are analyzed by u-sing the finite element method based on the GL specification.Meanwhile,the paper presents the detail cal-culation process of synthetic SN curve.It effectively solves the problem of yaw brake disc strength cal-culation,and provides credible technical support for the operation of wind turbines.

  3. Fuzzy fault tree analysis on hoist disc brake%提升机盘式制动器的模糊故障树分析

    Institute of Scientific and Technical Information of China (English)

    晋民杰; 郭空斐; 张帅; 杨明星

    2013-01-01

    In view of insufficiencies such as data lacking,environmental fuzziness and inaccurate data at analyzing the reliability of the hoist disc braking system at present,the fuzzy set theory was introduced into the fault tree analysis of the hoist disc brake.In addition,triangular fuzzy numbers were applied to characterize the fault occurrence probability of the hoist disc brake,and fuzzy fault tree was set up,which solved the inaccurate probability excellently.%针对目前提升机盘式制动系统进行可靠性分析时存在的数据不足和环境模糊性及数据的不精确性的问题,将模糊集合理论引入到提升机盘式制动器的故障树分析中,用三角模糊数刻画提升机盘式制动系统事件发生的概率,建立了模糊故障树,较好地解决了事件概率值不精确的问题.

  4. Stress analysis for disc of wind turbine spindle brake%风电主轴制动器制动盘的应力分析

    Institute of Scientific and Technical Information of China (English)

    刘莹; 王珊; 罗院明; 殷艳飞; 胡育勇

    2015-01-01

    In this paper,wind power spindle brake discs were carried out on three-dimensional solid model by ANSYS,while mechanical stress and thermal stress field were performed for this model of emergency braking. The results showed that the brake disc mechanical stress and thermal stress field both present a symmetrical distribution. Among them,brake disc mechanical maximum stress was shown on the outermost bolt holes for 39. 79 MPa;Ther-mal stress field,the maximum thermal stress occurs when braking time 7. 89 s,located inside of the friction zone and non-friction zone at the junction to reach 289 MPa;Both less than the material yield limit of 345 MPa,and the max-imum thermal stress was greater than mechanical stress. Thus the thermal stress was the main factor that caused the failure of brake disc.%利用ANSYS软件建立了风电主轴制动器制动盘三维实体模型,分析了紧急制动工况下其机械应力场和热应力场。结果表明:制动盘机械应力场和热应力场均呈对称分布。其中,制动盘机械应力最大值出现在最外层螺栓孔处,为39.79 MPa;热应力场中,最大热应力值发生在制动时间7.89 s时,位于摩擦区域内侧与非摩擦区交界处,达到289 MPa;两者均小于材料的屈服极限345 MPa,且热应力最大值远大于机械应力最大值,由此可知热应力是引起制动盘失效的主要因素。

  5. Inhomogeneity of Microstructure and Damping Capacity of a FC25 Disc-Brake Rotor and Their Interrelationship

    Science.gov (United States)

    Park, Jongbin; Han, Jeongho; Lee, Seung-Joon; Yi, Kyoungdon; Kwon, Chelwoong; Lee, Young-Kook

    2016-08-01

    The objective of the present study was to investigate the inhomogeneity of microstructure and damping capacity of a FC25 disc-brake rotor made of gray cast iron (GCI) and their interrelationship. The rotor had inhomogeneous microstructure due to different cooling rates caused by the position of inlets in a mold during casting. The volume fraction and size of graphite decreased with increasing cooling rate. A maximum deviation of the volume fraction of graphite within the rotor was approximately 2 pct, whereas that of the total perimeter of graphite per unit area was approximately 33 pct. Damping capacities measured at the first vibrational mode of both the real rotor and cantilever specimens, which were taken from four different regions within the rotor, depended on the location within the rotor. This result indicates that the damping capacity of the rotor is influenced by the inhomogeneous microstructure; particularly, the damping capacity was proportional to the total perimeter of graphite per unit area. Therefore, it was concluded that the damping of the GCI rotor used in the present study occurs primarily by the viscous or plastic flow at the interphase boundaries between the pearlite matrix and graphite particles at least at the frequencies of below 1140 Hz.

  6. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXVI, I--CATERPILLAR LUBRICATION SYSTEMS AND COMPONENTS, II--LEARNING ABOUT BRAKES (PART I).

    Science.gov (United States)

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE FUNCTIONS OF DIESEL ENGINE LUBRICATION SYSTEMS AND COMPONENTS AND THE PRINCIPLES OF OPERATION OF BRAKE SYSTEMS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) THE NEED FOR OIL, (2) SERVICE CLASSIFICATION OF OILS, (3) CATERPILLAR LUBRICATION SYSTEM COMPONENTS (4)…

  7. Study on Thermal Properties of Ventilated Disc Brake of Different Materials%不同材料的通风盘式制动器散热特性研究

    Institute of Scientific and Technical Information of China (English)

    郭伟捷; 张福生

    2016-01-01

    主要研究制动盘热量的产生机理以及散热过程,结合ANSYS CFX软件,模拟计算奔驰C200在紧急制动情况下,速度从90 km/h下降到0 km/h的过程中,不同材料的通风盘式制动器的制动盘的热量分布情况,得到不同材料制动盘散热特性,为企业生产盘式制动器提供合理的参考。%This paper mainly studied the heat generation and heat dissipation of ventilated disc brakes of different materials .By use of ANSYS CFX software ,the paper simulated the heat distribution of the brake disc of Mercedes‐Benzes C200 in emergency brake situation from 90 km/h to zero .The study on the different material of ventilated disc brakes reveals the thermal distribution of brake disc materials with different thermal properties .This work may provide a valuable .reference for the brake manufacturers .

  8. 基于有限元的轿车用制动盘轻量化可行性研究%Research on Weight Reduction of Brake Discs of Cars by Using Finite Element Method

    Institute of Scientific and Technical Information of China (English)

    崔世海; 袁健; 李海岩; 李向楠

    2013-01-01

    针对某型车用制动盘,建立了多个紧急制动工况下 SiCp/A356铝基复合材料制动盘和 HT250铸铁制动盘的三维瞬态热机耦合计算模型,运用有限元方法模拟了盘式制动器的制动过程。通过分析比较不同厚度两种材料的制动盘在紧急制动工况下应力场与温度场的分布,讨论了 SiCp/A356代替 HT250的减重效果,用仿真实验验证了铝基复合材料制动盘应用于乘用车的可行性。%Thermo-mechanical coupling finite element models of brake discs made of aluminum matrix composites (SiCp/A356) and cast iron(HT250)for passenger cars under different emergency braking conditions were deveoped. The braking process for brake discs were simulated by using finite element method. By analyzing distributions of the temperature field and stress field of the two brake discs with different thickness under emergency braking conditions,the weight reduc-tion of the brake discs by using SiCp/A356 to substitute for HT250 was studied and the simulation resusts showed that the brake discs made of aluminum matrix composties can be used for passenger cars.

  9. 一种汽车盘式电磁制动器的研制%Research and manufacture of electromagnetic brake disc on automobile

    Institute of Scientific and Technical Information of China (English)

    龙云梅; 林秋逢; 曾竞; 何荣欣; 彭马保; 曾文高; 陈伟涛

    2013-01-01

    为解决目前汽车液压制动系统存在结构复杂、质量大、能源消耗大等问题,将电磁制动技术应用到汽车制动系统中.开展了盘式电磁制动器增力机构建模和应力仿真分析,建立了制动踏板行程与电流大小以及制动力之间的对应关系,提出了以电磁铁作为动力源,通过增力机构把电磁力放大到预期制动力推动摩擦片工作而实现汽车制动的方法;在理论分析和试验的基础上对电磁力控制、汽车防抱死性能、制动热稳定性等多方面进行了评价;对实体模型的制动稳定性、电磁力随衔铁与铁芯之间距离的变化关系、电磁线圈通电电流与踏板行程之间的变化关系等进行了试验.试验结果表明:电磁铁力达到780 N,制动系统反应时间为0.019 6 s,均符合汽车制动要求;电磁制动系统相比液压制动系统具有反应迅速、结构简单以及更易于集成化和远程控制等特点.%In order to solve the problem of the hydraulic brake system of automobile for its complicate structure, heavy weight and great drain on the resources, the electromagnetic brake technology was applied to the automobiles. After the analysis of disc electromagnetic brake reinforcement structure modeling and stress simulation, the corresponding relationship between the brake pedal travel, current size and braking force was established. A method was presented that taking electromagnetic as the power source and through the reinforcement structure enlarge the electromagnetic force to the expected brake force and drive the friction brake to make the car brake become true. Based on theoretically calculation and experiment, the control of electromagnetic force, ABS performance and the thermal stability of the brake were evaluated. On the solid model, the stability of electromagnetic brake, the varing of the electromagnetic force between the distance of gag bit and iron core, the varing between the current of the

  10. 城市轨道交通列车3次紧急制动工况下的制动盘热容仿真%Thermo-mechanical Coupling Simulation of Brake Disc during 3 times Emergency Braking

    Institute of Scientific and Technical Information of China (English)

    张立国

    2013-01-01

    The design of urban rail transit system must satisfy the requirements of three times emergency braking, so it is necessary to analyze the thermal capacity of brake disc in the condition of three times emergency braking. Based on finite element analysis with heat coupling, the transient temperature field and stress field contours could be obtained by creating simulation model of the brake disc, setting boundary conditions by using the simulation parameters according to train operation data, and the finite element software ANSYS. The result of numerical simulation indicates that the method based on ANSYS is effective, and the peak temperature during three times emergency braking is about 293°, the maximal stress is about 135 MPa, which could meet the design requirements of operation.%城市轨道交通列车制动系统的设计需要满足3次紧急制动的需要,因此有必要对3次紧急制动工况下的制动盘热容量进行分析.基于有限元热机耦合仿真方法,通过建立的制动盘仿真模型,根据列车运行参数设置边界条件及仿真参数,利用有限元软件ANSYS计算得到瞬态温度场、应力场分布.仿真结果表明,基于ANSYS的有限元方法用于制动盘3次紧急制动工况分析的方法正确,根据设定的站间距分析的3次紧急制动工况下制动盘最高温度约293℃,最大应力约135 MPa,满足列车运行设计要求,可为制动盘的工程应用提供参考.

  11. Residual Stress Measurement of Gray Iron Braking Disc%灰铸铁制动盘铸件残余应力的测定

    Institute of Scientific and Technical Information of China (English)

    陈萌; 彭金花; 杨弋涛

    2013-01-01

    借助X射线应力仪对不同灰铸铁制动盘铸件进行了应力测试,使用铸造模拟软件ADSTEFAN求解了铸件的残余热应力,结果表明:(1)灰铸铁制动盘铸件进行短时间的自然时效对残余应力没有明显影响;(2)制动盘铸件表面应力分布与其结构和冷却速度均有较大的关联;(3)铸件的弹性模量增加,残余热应力也相应增加,在其余条件不变的情况下,残余热应力与弹性模量呈线性关系;铸件的热膨胀系数增加亦使相应的残余热应力值增加,但不存在明显的线性关系.%The stresses of different gray iron braking discs were measured by using X-ray stress instrument,and the foundry simulation software ADSTEFAN was used to calculate residual thermal stress of the castings.The results showed:(1)natural aging of the gray iron braking disc castings for short time hadn't obvious effect on their residual stresses; (2)there is quite close relationship between the surface stress distribution of the braking disc castings and their configuration as well as their cooling rate; (3)when elastic modulus of castings increasing,their residual stress also increased ;when the other conditions being unchanged,the residual thermal stress and elastic modulus presented a linear relationship;the increasing of thermal expansion coefficient also caused the corresponding residual stress increasing,but they hadn't obvious linear relationship.

  12. 三相盘式电动机的制动性能%Analysis on the Braking Performance of Three-phase Disc Motors

    Institute of Scientific and Technical Information of China (English)

    周佰君

    2014-01-01

    Factors to cause the unstable braking perfor-mance of the disc motor in the electric hoisting equipment were analyzed, especially, the synchronous problems oc-curred in the group of hoisting equipment, in which many sets of disc motor were employed were studied. Then, the relative means to solve these problems were suggested.%分析造成盘式电机在电动葫芦中制动性能不稳定的因素,特别是在群吊起重设备中多台三相盘式电动机使用时出现的同步问题,并提出了相应的解决措施。

  13. 机动车坡道驻车制动效能检验的现状与探新%Status and New Exploration on the Performance Test of Automotive Vehicle Rampway Hand Brake

    Institute of Scientific and Technical Information of China (English)

    黄俊平

    2011-01-01

    By analyzing the status of the performance test of automotive vehicle rampway hand brake, the paper points out the problems of the current test method that test line desktop brake test results replace the actual rampway hand brake performance of vehicle, tries to explore the accurate,safe, convenient, economical way to test motor vehicle parking by developing the simulation platform of automotive vehicle rampway hand brake.%文章通过对机动车驻车效能检验的现状分析,指出了目前以检测线台式制动方式检验结果代替车辆在实际坡道驻车制动效能的检验方式所带来的一些问题,提出了通过研发机动车坡道驻车制动模拟平台,探索精确、安全、便捷、经济的机动车驻车检验方式.

  14. Coupling Analysis of Temperature and Stress Fields for Brake Disc on Power Car%动车制动盘温度场和热应力场的耦合分析

    Institute of Scientific and Technical Information of China (English)

    张涛; 王梦昕; 丁亚琦; 王红; 商跃进

    2011-01-01

    随着高速列车运行速度的不断提高,紧急制动时制动盘的温度急剧增加,对其性能要求越来越高.根据传热学原理建立了高速列车动车制动盘的热-结构耦合模型,利用ANSYS软件对350 km/h动车组动车制动盘在紧急制动工况下的温度场和热应力场进行耦合仿真分析.结果表明:在57 s左右时,温度达到最大值418℃,满足锻钢对温度性能的要求;在50 s左右时,应力达到最大值772MPa,满足锻钢对强度性能的要求.仿真分析结果可作为制动盘设计和选材的参考依据.%With the speed of high-speed train continuously increasing,the temperature of brake discs increases sharply when the train takes emergency braking. Therefore, the performance demand for brake disc is higher and higher. According to heat transfer principle, the coupling model of hot-structure is established for brake disc on power car of high-speed train. With ANSYS finite element software,the value of temperature and thermal stress fields for brake disc on power car of high-speed train is simulated in emergency braking. Simulation results show the following: in about 57 s, brake disc will reach the max temperature of 418 ℃. It meets the performance of forging steeL And in about 50 s,brake disc will reach the max stress of 772 Mpa. And it satisfies the strength requirements. The simulation result can provide the reference for brake disc design and material.

  15. Tribological properties of nonasbestos brake pad material by using coconut fiber

    Science.gov (United States)

    Craciun, A. L.; Pinca-Bretotean, C.; Utu, D.; Josan, A.

    2017-01-01

    In automotive industry, the brake system is influenced by a large number of variables including geometry of components, materials of brakes, components interaction and many operating condition. Organic fiber reinforced metallic friction composites are increasingly being used in automotive brake shoes, disc and pads, linings, blocks, clutch facings, primarily because of awareness of health hazards of asbestos. Current trend in the research field of automotive industry is to utilization of different wastes as a source of raw materials for composite materials. This will provide more economical benefit and also environmental preservation by utilize the waste of natural fibre In this paper it has performed a tribological study to determine the characteristics of the friction product by using coconut natural fibred reinforced in aluminium composite. In this sense, two different laboratory formulation were prepared with 5% and 10% coconut fibre and other constitutes like binder, friction modifiers, abrasive material and solid lubrificant using powder mettallurgy. These dnew materials for brake pads are tested for tribological behaviour in a standard pin on disc tribometer. To know the wear behavior of composite materials will determine the parameters that characterize there tribological properties.

  16. Thermal-structure Coupling Analysis on Disc Brake of Mineral Car%矿车盘式制动器热-结构耦合分析

    Institute of Scientific and Technical Information of China (English)

    刘莹; 毕勇强; 宋涛; 杜军华; 杨鹤清

    2015-01-01

    研究矿车盘式制动器耦合场的分布规律。采用温度场与应力场直接耦合方法,根据矿车制动摩擦副的实际尺寸及热传导的原理,建立摩擦副三维瞬态热-结构耦合的有限元模型,对制动器在紧急制动工况下进行数值模拟。结果表明,耦合场下制动盘温度场、应力场都呈现带状分布,温度与应力的最大值出现在摩擦盘与摩擦片接触挤压处,且应力最大值的出现稍滞后于温度最大值,这说明了二者之间具有耦合特性;摩擦副径向、轴向具有较大的温度分布梯度,因此会产生较大的热应力,对制动器摩擦副材料造成热冲击和热疲劳,严重时可能会导致制动盘出现裂纹。%The distribution of a mineral car disc brake coupling field was studied based on direct coupling method of temperature field and stress field.According to the real dimension of the friction pairs,the model of three⁃dimensional tran⁃sient thermal⁃structure coupling finite element was established and the emergency braking condition of mineral car was nu⁃merical simulated based on the principle of heat conduction. The results show that there are coupling characteristics be⁃tween the temperature and stress field,which are shown zonal distribution,the maximum temperature and stress are concen⁃trated on the extrusion area of friction disc and friction plate,and the emergence of maximum stress lags behind the maxi⁃mum temperature.There is a large temperature gradient in radial and axial direction of friction pairs,which produces large thermal stress and causes thermal shock and thermal fatigue on the brake friction pair materials, and may even lead to crack of brake disc in serious cases.

  17. Design of Online Detection System for Natural Frequency of Brake Discs%制动盘固有频率在线检测系统的设计

    Institute of Scientific and Technical Information of China (English)

    褚志刚; 周亚男; 蒋忠翰; 张昌福

    2012-01-01

    In order to obtain the natural frequency of brake discs rapidly and accurately,an online detection system is designed and developed in this paper.The system is composed of sensors,data acquisition hardware,data acquisition and analysis software module,online detection software module and controlled circuit.The design principle and the implementation method of the system are introduced.The application results show that the detection system has good performances and can detect the natural frequency of brake discs rapidly and accurately,and display the judgment results intuitively.%为了快速准确的完成对制动盘固有频率的检测,开发了一套在线检测系统。该系统由传感器、数据采集硬件、数据采集及分析软件模块、在线检测软件模块及控制电路构成。详细介绍了系统的设计,论述了系统的检测原理和实现方法。应用结果表明:本系统性能稳定,能快速准确地完成对制动盘固有频率的在线检测,并直观给出制动盘合格性的判定结果。

  18. Nb在高导热铸铁制动盘中的应用%Application of Niobium to High Thermal Conductivity Cast Iron Brake Disc

    Institute of Scientific and Technical Information of China (English)

    周文彬; 朱洪波

    2011-01-01

    在CE为4.4%~4.5%的高导热铸铁制动盘中加入不同量的铌合金,研究了Nb对其组织和力学性能的影响.结果表明,CE为4.4%、w(Nb)量为0.09%时,高导热铸铁制动盘石墨组织细化,力学性能得到一定的提高,磨损量降低,制动盘的抗热裂性提高.%Different amount of niobium alloy was added into the high thermal conductivity cast iron with CE of 4.4%~4.5% used for brake disc,and the effect of the niohium on the microstructure and mechanical properties of the casting were investigated. The result showed that,when CE was of 4.4%,Nb was of 0.09% .the graphite of the high thermal conductivity cast iron brake disc became finer,its mechanical properties were increased in some degree,its wear loss was reduced,its hot cracking resistance was improved.

  19. 蠕铁制动盘灰斑缺陷的消除方法%Elimination Method of Gray Spot Defects of Vermicular Iron Brake Disc

    Institute of Scientific and Technical Information of China (English)

    任桂香; 张益忠

    2012-01-01

    The reason causing the gray spot defects of the vermicular iron brake disc used for the railway coach and the factors influencing the defect formation was analyzed,as well as the chemical composition of the casting,the composition of the vermicularizing alloy,the process parameters and method was adjusted.lt was found that the main factors influencing the gray spot formation were as follows: the residual magnesium content, residual rare earth content, sulfur content, the gas venting condition of the mould cavity,solidification time oi the casting and so on,as well as the optimal control range of the residual magnesium and rare earth contents for the vermicular iron brake disc were determined.%对铁路客车用蠕墨铸铁制动盘出现的灰斑缺陷的形成原因和影响因素进行了分析,并对铸件的化学成分、蠕化剂成分、工艺参数及方法进行了调整.查明了影响灰斑形成的主要因素是w(Mg残)、w(RE残)、w(S)量、型内气体排放情况以及铸件凝固时间等,并确定了蠕墨铸铁制动盘的w(Mg残)和w(Re残)量的最佳控制范围.

  20. 自行车碟刹制动距离测试系统的设计与实现%Design and implementation of bicycle disc braking distance test system

    Institute of Scientific and Technical Information of China (English)

    陈梦群; 杨成忠

    2012-01-01

    随着碟刹的使用越来越普及,刹车的可靠性测试显得尤为重要,而国内市场上尚没有针对碟刹的测试系统.针对这一问题,设计了一套自行车碟刹制动距离测试系统.首先建立了自行车的刹车模拟装置,然后在模拟装置上安装了拉力传感器和速度传感器对其进行实时监测,传感器信号由数据采集卡采集并上传至上位机,上位机软件分析数据后下发命令控制模拟装置的刹车过程,并实时显示拉力值、速度值和制动距离等.通过多次制动距离测试,求平均值,确定了碟刹的制动距离,最后进行了试验验证.研究结果表明,该测试系统能够较准确地测量出自行车的制动距离,并且性能稳定,简单易操作,实用性强,具有良好的实际应用价值.%As the bicycle disc brake is getting more and more popular,the reliability testing is very important. But in the domestic market, there is no test system for the disc brake. Aiming at this problem,a system was designed to test the braking distance of the bicycle disc brake. The bicycle simulator was firstly created to simulate bicycle braking. Then a tension sensor and a speed sensor were installed on the braking simulator. The tension sensor was used to indirectly measure the power of gripping on the handlebar when the bicycle simulator was braking. The speed sensor was used to measure the speed of the inertial disc throughout the braking process. The signals of the two sensors were collected by the data acquisition card. The data of the sensors from the data acquisition card was gotten and analyzed, the commands were sent to control of the braking process, the data was real-time displayed,including tension value, velocity,the braking distance and so on. The braking distance of a bicycle disc brake was determined by the average of multiple test results. Finally the verification experiment was done in a factory producing Bicycle disc brakes. The results indicate that the

  1. Simulation and analysis of vehicle stability based on ADAMS/CAR differential brake

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To improve the braking safety of automobiles, the author studied the effect of differential brake on the stabilities. To analyze the mechanical characteristics of differential brake, automotive subsystem models were built by applying ADAMS/CAR, and automotive mechanics simulation model was built by setting the main subsystems such as body, engine and brake. The simulation model studied the distribution mode of three kinds of differential brake, and beeline braking stability and turning braking stability wer...

  2. Research on Friction Thermodynamics of Mine Locomotive Brake Disc%矿机车盘式制动器摩擦热力学研究

    Institute of Scientific and Technical Information of China (English)

    张森; 肖林京; 张玉龙; 于鹏杰

    2015-01-01

    针对矿机车制动盘因热裂纹造成的制动失效问题,对机车制动过程中的摩擦热力学计算展开研究。根据摩擦功率法确定出摩擦生热的热流密度,得出热分析的边界条件,分析了热对流与热辐射模型,建立了具有表面径向裂纹的制动盘有限元模型,采用子模型技术对其进行热-结构耦合分析,结果表明,温度变化的最小熵效应明显,裂纹的远心端点在热载荷作用下产生较大的拉应力并引发裂纹扩展。%Aiming at the mine locomotive brake disc failure problem that caused by the hot crack, the thermodynamic calculation of locomotive brake friction is researched. According to the friction power method, the heat flux density is determined, and the boundary conditions for thermal analysis are obtained. Then the heat convection and thermal radiation model are analyzed, and brake disc finite element model is established with radial crack. The submodel technology is used for the couple of thermal-structure analysis, and the results show that the minimum entropy effect is quite obvious during the temperature changes, and large tensile stress is produced in the crack endpoint, which will cause crack propagation.

  3. Optimal Design of Vehicle Disc Brake Integrated Electromagnetism and Friction%集成电磁与摩擦的车辆盘式制动器优化设计

    Institute of Scientific and Technical Information of China (English)

    王奎洋; 唐金花; 李国庆; 袁传义

    2013-01-01

    Structure and working principle of vehicle disc brake integrated electromagnetism and friction are introduced. Based on optimal theory ofmulti objections, the disc brake integrated electromagnetism and friction is researched comprehensively, and the performance indexes and geometric constraint condition which must be satisfied during the design of disc brake are analyzed. The optimal mathematical model ofmulti objections which takes maximum brake torque and minimum temperature elevated of brake as objective function is built. Multiple targets are transformed into single target through multiplication and division of function method unified targets, and are solved with optimization. The optimal result shows that the parameter scheme of structure which is got through optimal design method may improve braking effect and the performance which shows ability to resist thermal decay of disc brake integrated electromagnetism and friction.%介绍了集成电磁与摩擦的车辆盘式制动器的结构和工作原理,基于多目标优化理论,通过对集成电磁与摩擦盘式制动器的深入研究,分析了该集成化制动器设计过程中必须满足的性能指标和几何约束条件,建立了以制动力矩最大和制动温升最小为目标函数的多目标化的优化数学模型,采用统一目标函数法中的乘除法将多目标转化为单一目标进行优化求解.优化结果表明,采用优化设计方法得到的结构参数方案改善了集成电磁与摩擦制动器制动效果和抗热衰退性能.

  4. Design and Analysis of Hydraulic System of Disc Brake for Downward Belt Conveyor%下运带式输送机盘式制动器液压系统设计与分析

    Institute of Scientific and Technical Information of China (English)

    刘灿杰; 贾跃虎; 刘志奇

    2011-01-01

    通过分析下运带式输送机制动工况的特点以及盘式制动器的优点,设计出适合各制动工况要求的新型盘式制动器液压系统.该液压系统具有松闸、保压、正常停车制动、超速制动、紧急制动和系统突然断电制动等功能.建立了系统的数学模型,将数学模型线性化后推导出了系统传递函数,分析了各元件参数对系统响应性的影响,为设计压力精细调节的制动器提供了理论基础.%The characteristics of braking condition of downward belt conveyor and advantages of disc brake were analyzed. A new hydraulic system of disc brake which met each braking condition requirement was designed. This hydraulic system have functions of loose braking, the normal parking braking, emergency braking and suddenly lose power braking. The mathematical model of this hydraulic system was established. The transfer function of this hydraulic system was deduced by the mathematical model linearization. The influences of the parameters to the response of the system were analyzed. The research work lays theory foundation for the design of brake with pressure fine adjustment.

  5. 49 CFR 238.431 - Brake system.

    Science.gov (United States)

    2010-10-01

    ... thermal damage to wheels or discs. (f) The brake system design shall allow a disabled train's pneumatic... 49 Transportation 4 2010-10-01 2010-10-01 false Brake system. 238.431 Section 238.431... Equipment § 238.431 Brake system. (a) A passenger train's brake system shall be capable of stopping...

  6. Finite Element Method of Thermoelastic Instability of Disc Brakes%盘式制动器热弹性不稳定性的有限元分析

    Institute of Scientific and Technical Information of China (English)

    王欲进; 李晓明

    2012-01-01

    采用有限元分析法分析盘式制动器热弹性不稳定性,建立了三维盘式制动器热力学分析模型,基于交错接触的中间处理器用来交换结果数据:温度,摩擦接触力,位移和变形.对制动盘的厚度变化(DTV)和温度的分布进行了计算,验证了有限元模型的可靠性,并确认了计算方案.为盘式制动器的选材、结构设计以及磨损提供了理论依据,对制动的振动和噪声研究有很好的工程使用价值.%The thermoelastic instability (TED was analyzed using the finite element analysis technique. The governing dynamic and heat equations were described. Three dimensional thermo-mechanical analysis model of the disc brake system was created. An intermediate processor based on the staggered approach was used to exchange result data: temperature, friction contact power, nodal displacement and deformation. Disc thickness variation (DTV) and temperature distribution of the disc were calculated, and the tendency and meaning of each result were discussed.

  7. Theoretical approach of disc brake system optimum design for drilling rigs%钻机盘式刹车系统优化设计的理论探讨

    Institute of Scientific and Technical Information of China (English)

    吕瑞典; 伍开松; 罗井泉

    2001-01-01

    The applied forces to braking disc and braking plier for discbrake system of drilling rigs are analyzed.Then the basic relationships of the consuming energy on the friction faces, forces and other factors are deduced.The expressions of energy transformation for disc brake system of drilling rigs are derived on the basis of the principle of energy conservation. By further analysis of the operating requirements of the disc brake system and main failure forms during braking periods, the theoretical curves of temperature change and consuming power changes are proposed.At case the optimum design model of the disc brake system for drilling rigs is established, and also some things related to the model are discussed.%分析了钻机盘式刹车系统中刹车盘和刹车钳的受力状态,导出了其受力和摩擦面上耗散功率等因素之间的基本关系式。根据能量守恒原理又推导了钻机盘式刹车系统的能量转换表达式。通过进一步分析盘式刹车系统的使用要求和刹车过程中失效的主要形式,提出了刹车盘摩擦表面温度变化的理想曲线和耗散功率变化的理想曲线。建立了钻机盘式刹车系统的优化设计模型,并进行了分析讨论。

  8. Finite Element Analysis(FEM) on Thermal Fatigue Failure of Water-cooling Disc Brake%水冷盘式制动器热疲劳失效有限元分析

    Institute of Scientific and Technical Information of China (English)

    蔡运迪; 唐文献; 黄秋芸; 王玲玲

    2012-01-01

    针对海洋钻井绞车在连续下钻过程中的制动工况,建立了水冷盘式制动器三维热-机耦合分析模型,运用大型有限元分析软件ABAQUS数值模拟了制动器的制动过程,获得了制动盘表面及内部温度场与应力场的分布特征,并以此为基础分析了制动盘热疲劳失效的机理.研究结果表明:连续制动工况下,制动盘的温度场与应力场相互耦合,两者具有相似的变化规律;周向热应力是形成制动盘表面初始裂纹的主要应力分量,在热应力反复作用下,该初始裂纹发展为粗大的裂纹,最终导致制动盘的断裂.分析结果与实际情况吻合较好,从而证明了该分析方法的正确性和可行性.%Aiming at the repeated braking conditions of offshore drilling drawworks during the round trip,a three -dimensional FEM of thermo-mechanical coupling analysis of the water-cooling brake disc was established. By using the FEA software ABAQUS,the repeated braking process was simulated. Distribution characteristics of the surface and inner temperature field and stress field were obtained,based on which, the thermal fatigue failure mechanism of brake disc was analyzed. The results show that,in the repeated braking,the temperature and stress of brake disc are coupled,and they have the similar variation disciplinarian. Thermal stress in the circular direction is the main stress for causing the initial cracks on the surface of brake disc. These cracks are getting larger under the effect of repeated thermal stress, eventually, inducing the fracture of brake disc. The analysis results are in good agreement with the practical situation, which prove the validity and feasibility of the analysis method used herein.

  9. Digital simulation and analysis on temperature f ield of wet multi-disc brake based on ABAQUS%基于ABAQUS的湿式多盘制动器温度场数值模拟分析

    Institute of Scientific and Technical Information of China (English)

    何建成; 张文明; 姜勇; 李荣昊; 朱利明

    2012-01-01

    以井下工程车辆的湿式多盘制动器为研究对象,建立了基于ABAQUS的湿式多盘制动器的热-机耦合有限元分析模型。通过对湿式多盘制动器温度场的数值模拟分析,得到了不同制动工况下湿式多盘制动器各摩擦副的温度变化曲线,为分析湿式多盘制动器的失效形式及原因提供了参考。%The paper established thermal-mechanical coupling FEM model of the wet multi-disc brake of an underground engineering truck based on ABAQUS.After the digital simulation and analysis of the temperature field of the wet multi-disc brake,the temperature variation curves of each friction pair at various braking modes were obtained.The curves offered references for analyzing failure forms and causes of the wet multi-disc brake.

  10. Negative Effect of Disc Thickness Variation on the Performance of Anti-lock Braking System and Its Control Method%制动盘厚薄差对ABS性能的负面影响及控制方法

    Institute of Scientific and Technical Information of China (English)

    张立军; 黄平宇

    2013-01-01

    A nonlinear braking dynamics model for a quarter car is established, which consists of a rigid-ring-based transient tire model and a disc brake model with consideration of disc thickness variation ( DTV). Based on the model and by using MATLAB/Simulink, the negative effects of DTV on the braking performance of ABS system with slip rate threshold control are analyzed, and a set of adaptive control parameters based on the degrees of DTV are proposed on the basis of optimization to suppress the negative effects of DTV. The results indicate that DTV has negative effects on wheel motion, braking performance and braking comfort, while the use of DTV adaptive control parameters though may deteriorate braking comfort, but can effectively improve wheel motion and braking performance.%建立了包含瞬态刚性圈轮胎模型、考虑制动盘厚薄差(DTV)的制动器模型的1/4车非线性制动动力学模型.基于该模型,利用MATLAB/Simulink软件分析了DTV对滑移率门限值控制下ABS制动性能的负面影响,并提出了一套抑制DTV影响的适应性控制参数.结果表明:DTV会对车轮运动状态、制动效能和制动舒适性产生负面影响,而采用DTV适应性ABS控制参数虽会恶化舒适性,但可改善车轮运动状态,提高制动效能.

  11. 海洋钻井绞车用水冷式制动盘瞬态温度场分析%Analysis of Transient Temperature Field of Water-Cooling Brake Disc in Offshore Drilling Drawworks

    Institute of Scientific and Technical Information of China (English)

    唐文献; 蔡运迪; 黄秋芸; 王飞

    2011-01-01

    对海洋钻井绞车用水冷式制动盘,建立了三维瞬态热-机耦合理论模型和有限元分析模型.运用有限元分析软件ABAQUS,对钻井绞车紧急制动工况进行了数值模拟,分析了制动盘瞬态温度场分别在半径方向、周向和不同厚度处的分布特征和变化规律.计算结果表明:紧急制动时,制动盘在径向与周向均存在很大的温度梯度,相比之下,径向的温度梯度更大;制动结束时刻,温度的影响层深度很浅,盘面瞬时温度很高且高温区域集中在制动盘摩擦表面的中部区域.很高的盘面温度在短时间得不到消散是导致制动盘高温氧化的重要原因.%Theoretical model and FEM of three-dimensional transient thermo-mechanical coupling of the water-cooing brake disc for offshore drilling drawworks are established, with the real conditions of the brake disc taken into account. By using FEA software ABAQUS, an emergency braking condition is simulated, and distribution characteristics and variation disciplinarian of transient temperature distribution in radial, circular and thickness are analyzed respectively. Simulation results reveal that temperature gradient in radial direction is larger than that in circular direction at an emergency braking. Besides, at the end of braking, the depth of temperature influence layer is small and transient temperature on the disc surface is very high. What's more, the high temperature zone will concentrate in the middle of the friction area of the brake disc. The very high temperature, which can not be abreacted in a short time on the surface, is a very important reason for the high-temperature oxidation of the brake disc.

  12. The Analysis of Ttransient Temperature Field Distribution of Vehicle Ventilated Disc Brake under Emergency Braking Condition%紧急制动工况下汽车通风盘式制动器瞬态温度场分布的研究

    Institute of Scientific and Technical Information of China (English)

    简弃非; 吴昊

    2016-01-01

    The ventilated disc brake which used in a passenger vehicle front wheel as the research object is set,its thermal-structure coupled three-dimensional finite element analysis model is set up. Then direct coupling method is adopt to simulate the transient temperature field of ventilated disc brake under emergency braking condition on the basis of model,eventually the distribution and change characteristics of temperature field of ventilated brake disc and pad in emergency braking are gotten. The results show that the temperature field distribution of brake disc is not axial symmetry in emergency braking,there are certain temperature gradient in radial,circumferential and axial three directions. The highest temperature of the brake disc appeared in 1. 91 s,the highest temperature is 227. 1℃. Meanwhile the ventilated disc brake bench test is carried on under the brake condition as same as the simulation a-nalysis,the obtained experimental result basic consistent with the result of the simulation calculation,thus the validi-ty of the simulation analysis is verified,and a theoretical basis for design and optimization of ventilated disc brake is provided.%以某乘用车前轮采用的通风盘式制动器为研究对象,建立其热-结构耦合的3维有限元分析模型.在此基础上采用直接耦合法对该通风盘式制动器在紧急制动工况下的瞬态温度场进行仿真分析,获得整个通风式制动盘和摩擦片在紧急制动过程中温度场的分布情况及变化特性.结果显示:在整个紧急制动过程中,制动盘温度场的分布不是轴对称的,其在径向、周向及轴向3个方向上均存在着一定的温度梯度;制动盘的最高温度出现在1.91 s,最高温度为227.1℃.同时对该通风盘式制动器进行了与仿真分析相同制动工况下的台架试验,所获得的实验结果与仿真计算结果基本一致,从而验证了仿真分析的有效性,为通风盘式制动器的设计及优化提供了理论基础.

  13. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXVII, I--CATERPILLAR STARTING (PONEY) ENGINE (PART I), II--LEARNING ABOUT BRAKES (PART II).

    Science.gov (United States)

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE CONSTRUCTION AND OPERATION OF DIESEL ENGINE STARTING ENGINES AND BRAKE SYSTEMS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) GENERAL DESCRIPTION, (2) OPERATION, (3) COMBUSTION SPACE AND VALVE ARRANGEMENT (STARTING ENGINES), (4) TYPES OF BRAKES, AND (5) DOUBLE…

  14. Experimental study using infrared thermography on the convective heat transfer of a TGV brake disc in the actual environment

    Science.gov (United States)

    Siroux, Monica; Harmand, Souad; Desmet, Bernard

    2002-07-01

    We present an experimental identification of the local and mean Nusselt number from a rotating TGV brake disk model in the actual environment and exposed to an air flow parallel to the disk surface. This method is based on the use of a heated thermally thick disk combined with the technique of temperature measurement by infrared thermography. The local and mean convective heat transfer coefficient from the disk surface is identified by solving the steady state heat equation by a finite difference method using the experimental temperature distribution as boundary conditions. The experimental setup is constituted of a model disk with all the representative parts of the actual TGV brake system. The disk and its actual environment are inside a wind tunnel test section, so that the rotational disk speed and the air flow velocity can be varied. Tests were carried out for rotational speeds w between 325 and 2000 rpm (rotational Reynolds number Re between 88,500 and 545,000), and for an air flow velocity U ranging between 0 and 12 m(DOT)s-1 (air flow Reynolds number Re0 between 0 and 153,000).

  15. Simulation analysis for effect of pad lining arc on disc brake squeal%摩擦衬片包角对盘式制动器尖叫影响的仿真分析

    Institute of Scientific and Technical Information of China (English)

    张立军; 陈前银; 刁坤; 孟德建; 余卓平

    2016-01-01

    摩擦衬片包角对制动尖叫具有重要影响。针对某通风盘式制动器,建立有限元复模态模型并通过尖叫台架试验进行了正确性验证。基于该模型针对5种包角水平的摩擦衬片,通过仿真计算分析其对制动尖叫倾向性的影响,并从制动块自由模态特性、盘块间接触压力分布、不稳定模态频率及模态耦合特性角度解释了不同摩擦衬片包角对制动尖叫的影响机制。分析表明:摩擦衬片包角的改变会同时引起制动块结构特性变化和接触压力分布的变化,进而引起不稳定模态数量、频率和模态耦合特性的改变。%Lining arc of brake pad has a very important effect on disc brake squeal.A finite element complex analysis model of a ventilated disc brake was established and validated through a bench test of brake squeal.Based on this model,the influence of pad lining arc on brake squeal trend was investigated using simulation of disc brakes with pads of five lining arcs.At the same time,the influence mechanism was studied from view points of natural vibration characteristics of brake pad,pressure distribution between pad and disc,instable modal frequencies and modal coupling. It was shown that the structural characteristics and pressure distribution variations due to pad lining arc variations can cause the change of instable modes,modal frequencies and modal coupling.

  16. Research on the On-site Training Exam System of Automotive Braking Machine%机车制动机现场培训考试系统的研究

    Institute of Scientific and Technical Information of China (English)

    张玲

    2015-01-01

    针对目前普遍存在机车司机培养时间短、 经验不足, 对机车操纵的熟练程度及对现象判断的准确性不高的问题, 采用气动技术、 依据流体力学理论, 设计开发了机车制动机现场培训考试系统. 经过在乘务员培训中的应用, 取得明显的效果, 提高了乘务员的制动机操作水平和对列车管判断的准确性.%The on-site training exam system of automotive braking machine was devised and developed with the pneumatic technology on the basis of liquid mechanics theory aimed at the problems such as short time of cultivation for the locomotive drivers, insufficient experience, and unskilled degree of controlling the locomotive, low accuracy to the estimation of the phenomenon. It was applied in the training of steward and achieved distinct effect, enhanced the level for steward to operate braking machine and judge the train braking pipe accurately.

  17. Characteristics and Application Examples of Nb-Containing Gray Iron Car-Used Brake Disc%含Nb灰铸铁轿车制动盘的特点及应用实例

    Institute of Scientific and Technical Information of China (English)

    征灯科; 朱洪波; 周文彬; 华勤; 翟启杰

    2011-01-01

    介绍了轿车制动盘的失效形式以及工况对其材料性能的要求,着重讨论了灰铸铁制动盘的特点、性能要求及Nb对其组织和性能的影响,并对灰铸铁制动盘生产中孕育剂的选用提出建议.给出了含Nb灰铸铁制动盘的应用实例.%The failure manner of the car-used brake disc and material properties requirements basing on its working conditions was introduced. As the emphasis, the characteristics and properties requirements of gray iron brake disc and. as well as, the influence of Nb on its structure and properties were discussed. In addition, the suggestion about how to select the inoculant in the gray iron disc production was proposed. The application example of Nb-containing gray iron brake dise was given.

  18. 基于汽车制动力平衡问题的研究%Automotive Braking Force Balance Based on Research

    Institute of Scientific and Technical Information of China (English)

    周劲松

    2014-01-01

    In braking tests on the car braking force balance analyzes the causes of miscarriage of justice, and propose effective test method for detecting balanced car braking force, in order to provide a reference for safe driving and road safety.%就制动试验对汽车制动力平衡误判的原因进行了分析,并提出有效的试验方法检测汽车制动力的平衡,以期为安全行车和道路安全方面提供参考借鉴。

  19. Simulation and Analysis on Disc Brake Vibration Based on Rigid-Flexible Coupling%基于刚柔耦合的盘式制动器振动仿真分析

    Institute of Scientific and Technical Information of China (English)

    张力; 谷正气; 李伟平; 梁小波; 彭国谱

    2011-01-01

    综合考虑摩擦特征和模态耦合,建立了基于刚柔耦合的矿用自卸车盘式制动器模型,以对其振动进行仿真分析.首次通过直接设置柔性体问的接触,模拟制动器典型制动工况.对其进行瞬态动力学分析.研究结果表明,部件间摩擦因数、部件阻尼对盘式制动器的振动有很大影响;合适的部件阻尼可有效提高制动系统的稳定性.%With concurrent consideration of friction feature and modal coupling, a model for the disc brake of a mining dump truck is built based on rigid-flexible coupling for the simulation and analysis of its vibration. It is for the first time by directly setting the contact between flexible bodies to simulate the typical braking condition of disk brake and conduct its transient dynamics analysis. The results show that the friction coefficient and the damping of components have significant influence on the vibration of disk brake and appropriate component damping can effectively improve the stability of brake system.

  20. Effect of surface texture and working gap on the braking performance of the magnetorheological fluid brake

    Science.gov (United States)

    Wang, Na; Li, Dong Heng; Li Song, Wan; Chao Xiu, Shi; Zhi Meng, Xiang

    2016-10-01

    In this paper, the effect of the surface textures of braking disc on the braking performance is experimentally investigated under the conditions of different working gaps and applied currents. For this purpose, a new configuration of magnetorheological fluid brake (MRB) with adjustable working gap is developed to improve the manufacturing accuracy and cost, and to reduce the problem of replacing the braking disc. In addition, the braking discs with three types of surface texture are designed and machined. Based on the test bed developed for the proposed MRB, a series of experiments are carried out on the manufactured prototype and the results are presented to obtain the relationship among the surface texture of the braking disc, applied current, working gap and the braking performance. The results show that the braking torque is significantly influenced by the working gap and surface texture of the braking disc, and the maximum braking torque is obtained on the conditions of 0.25 mm working gap and the braking disc with square surface texture.

  1. Simulation of three-dimensional transient temperature field and thermal stress of airplane braking disc%飞机刹车副的三维瞬态温度场和热应力仿真分析

    Institute of Scientific and Technical Information of China (English)

    韩建辉; 聂宏; 魏小辉

    2012-01-01

    飞机的刹车装置是利用摩擦产生制动将高速运动的动能转换成热能,产生的高温使摩擦材料的物理、化学性质发生变化,由于较大的温度梯度的出现使刹车盘上存在非常大的热应力,使刹车系统的安全性能受到威胁,所以对刹车盘瞬态温度场和由此产生的热应力进行计算就显得非常必要.针对飞机刹车盘瞬态温度场和热应力仿真建立了有限元模型,有限元网格划分采用六面体结构.对刹车过程进行了理论分析与计算,并运用MSC PATRAN/MARC软件对其进行了仿真计算.刹车副的最高温度为1 020℃,与刹车副温度场的经验值基本吻合,在以温度场和刹车副的位移约束为边界条件计算得到刹车副的热应力.热应力的分布特点和温度梯度是一致的,所以热应力的计算结果是合理可行的,可以应用于飞机刹车盘设计过程中.%The brake system of airplanes transforms kinetic energy into heat by friction. Heat causes physical and chemical instability of brake disc,a large temperature gradient result in a very large thermal stress on the brakes,which results in insecurity to the brake system. Therefore, the calculation of the transient temperature field and thermal stress on the brake disc becomes essential. Establish a finite element model for transient temperature field and thermal stress of the aircraft brakes, the grid is knitted from hexahedral. Concentrate on theoretical analysis and digital simulation by MSC PATRAN/MARC. The result meets the actual braking condition, which benefit to the design of aircraft brakes.

  2. Impacts of Initial SRO on Thermo-mechanical Coupling Characteristics of Disc Brake%初始端面跳动对制动器热-机耦合特性的影响

    Institute of Scientific and Technical Information of China (English)

    孟德建; 张立军; 余卓平

    2012-01-01

    Supposed disc inner and outer surfaces have the same initial surface run-out (SRO) with 2 order sine function characteristics, the transient thermo-mechanical coupling dynamic model of ventilated disc brake with asymmetrical outer and inner thickness was established by means of Msc-marc software. With distribution characteristics of disc temperature field, normal stress field, thermal coning and thickness variation for the evaluation, the impacts of initial SRO on brake thermo-mechanical coupling characteristics were analyzed under emergency braking condition. The simulation results show that initial SRO, both its direction and amplitude, have significant effects on brake thermo-mechanical coupling characteristics.%假设制动盘内、外盘面具有相同的2阶正弦函数特征的初始端面跳动,针对内外侧壁厚不等的通风盘式制动器,利用Msc-marc软件建立了瞬态热-机耦合动力学仿真模型.以制动盘盘面温度场、法向应力、翘曲及厚度变化的分布特性为评价指标,在紧急制动工况下,分析了初始端面跳动对制动器热-机耦合特性的影响.研究发现,初始端面跳动的方向和大小对制动器热-机耦合特性具有显著影响.

  3. Simulation and analysis of vehicle stability based on ADAMS/CAR differential brake

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To improve the braking safety of automobiles, the author studied the effect of differential brake on the stabilities. To analyze the mechanical characteristics of differential brake, automotive subsystem models were built by applying ADAMS/CAR, and automotive mechanics simulation model was built by setting the main subsystems such as body, engine and brake. The simulation model studied the distribution mode of three kinds of differential brake, and beeline braking stability and turning braking stability were simulated. It shows that differential brake can amend turning shortage of automobile brake and improve its braking stability, but the effect of automobile mass on its braking stability is great. So the distribution mode of braking force and the effect of mass change should be considered while differential brake is applied.

  4. 49 CFR 570.59 - Service brake system.

    Science.gov (United States)

    2010-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY...-second of an inch over the fastener, or one-sixteenth of an inch over the brake shoe on bonded linings or... surface. Drum brake linings shall be securely attached to brake shoes. Disc brake pads shall be...

  5. Analysis and Improved Design of G58 Wind Turbine High-speed Shaft Brake Disc Crack%G58风电机组高速轴刹车盘裂纹分析及其改进设计

    Institute of Scientific and Technical Information of China (English)

    李成哲; 朱先勇; 刘润

    2014-01-01

    The brake disc is easy to crack during G58-850 wind turbine processing, which can make many units stop and affect the normal operation of the whole brake system. This paper analyses the cause of wind turbine brake disc crack, such as geometric shape and stress distribution. Some methods for reducing the crack are put forward, such as improving microstructure, chemical composition and heat treatment processing.%G58-850风电机组在实际运行过程中,刹车盘极易产生裂纹,造成多台机组停转,影响整套制动系统的正常运行。本文从几何外形、应力分布等方面分析了风电机组刹车盘上裂纹产生的原因,并提出了从改善金相组织、化学成分及热处理工艺等方面降低裂纹产生的方法。

  6. Automotive mechatronics automotive networking, driving stability systems, electronics

    CERN Document Server

    2015-01-01

    As the complexity of automotive vehicles increases this book presents operational and practical issues of automotive mechatronics. It is a comprehensive introduction to controlled automotive systems and provides detailed information of sensors for travel, angle, engine speed, vehicle speed, acceleration, pressure, temperature, flow, gas concentration etc. The measurement principles of the different sensor groups are explained and examples to show the measurement principles applied in different types. Contents Basics of mechatronics.- Architecture.- Electronic control unit.- Software development.- Basic principles of networking.- Automotive networking.- Bus systems.- Automotive sensors.- Sensor measuring principles.- Sensor types.- Electric actuators.- Electrohydraulic actuators.- Electronic transmission control.- Electronic transmission control unit.- Modules for transmission control.- Antilock braking system.- Traction control system.- Electronic stability program.- Automatic brake functions.- Hydraulic modu...

  7. Optimization Analysis of the Sealing Performance of Rectangular Sealing Ring of Automotive Brake Fluid Filling Gun%汽车制动液加注枪矩形密封圈性能的优化分析

    Institute of Scientific and Technical Information of China (English)

    张和平; 黄华坤

    2013-01-01

    利用有限元分析软件ANSYS,对汽车制动液加注枪与壶口的矩形密封圈的密封性能进行有限元分析.通过分析影响密封性的因素,如压缩率、摩擦因数、壶口内径、壶口壁厚,得到密封面接触压力随各因素变化的关系曲线.通过正交试验,确定各因素对密封面接触压力的贡献率,得到密封性能最优时各因素的取值.结果表明,压缩率对密封性的影响最大,其次是摩擦因数、壶口内径和壶口壁厚.%The sealing performance of the rectangular sealing ring between the automotive brake fluid filling gun and the spout of brake fluid pot was analyzed by using finite element analysis software ANSYS.By analyzing the factors influencing the sealing performance,such as compression rate,friction coefficient,the spout inner diameter and wall thickness,the variations of sealing surface contact pressure along with these factors were obtained.Through orthogonal experiments,the contribution rate of each factor on the sealing surface contact pressure was determined,and the optimal value of each factor was selected to get the best sealing performance.The results show that the influence of compression ratio on the sealing performance is the biggest,followed by friction coefficient,the spout inner diameter and wall thickness of brake fluid pot.

  8. 高速列车锻钢制动盘多裂纹间作用机制研究%Study on Interaction Mechanism between Cracks at Forged Steel Brake Disc for High Speed Train

    Institute of Scientific and Technical Information of China (English)

    石晓玲; 李强; 薛海; 赵方伟

    2016-01-01

    To address the multiple crack problem occurring to the forged steel brake discs of high-speed train in the practical application,the interaction mechanism between cracks was studied by combining the 1 ∶1 bench test with finite element calculation.The findings from the 1∶1 bench test on brake disc proved a certain regu-larity in crack propagation.In order to further investigate the interaction mechanism between cracks,the ther-mal stress on brake disc was calculated in the case of emergency braking three times with the speed of 200 km/h by using the finite element method.Based on the above research,the crack model of brake disk surface was established using FRANC3D software to analyze the stress intensity factor of crack front and the interaction mechanism between cracks.The results showed that the interaction between the main cracks and secondary cracks changed with the change of the number of cracks and the crack location.Different ratio between the depth and length had different effect.The more the number of the radial cracks was,the slower surface crack growth.As a result,the fatigue failure of the brake disc was effectively delayed.The analysis results were con-sistent with the interaction regularity of the brake disc from the 1∶1 bench test.%针对高速列车锻钢制动盘在实际运用中出现的多裂纹问题,通过1∶1台架试验与有限元计算相结合的方法研究了制动盘多裂纹间的作用机制。依据制动盘1∶1台架试验结果发现,盘面裂纹的扩展具有一定的规律性。为进一步研究裂纹间的作用机制,运用有限元方法计算了制动盘在3次连续200 km/h 紧急制动后的热应力。在此基础上,采用 FRANC3D 软件建立了制动盘盘面的裂纹模型,分析研究了制动盘裂纹前缘的应力强度因子及多裂纹间的作用机制。分析结果表明,主、副裂纹间的相互作用随着裂纹数量和空间位置的变化而变化,不同的深长比有不同的

  9. Research on the Feasibility of Application of ABS in Hydraulic Disc Brake%ABS在液压盘式刹车中应用的可行性研究

    Institute of Scientific and Technical Information of China (English)

    石固欧; 刘威

    2013-01-01

    The anti-lock braking system (ABS) of automobiles has such advantages as slippage and lock prevention,relatively short distance of braking and reduction of tyre wear.Therefore,the ABS control strategy was introduced to the design of the hydraulic system of drilling and workover rigs.The neotype hydraulic control system of hydraulic disc brake with both manual and automatic operation modes was built,which could achieve ABS control strategy.A comparative braking dynamic simulation analysis of the hydraulic system and running conditions with and without the ABS system was conducted.The analysis shows that selection of the proper duty cycle of the ABS system can get closer to the braking time and angle displacement without the ABS system.The better pressure regulation waveform had been obtained.Regulation of the ABS control strategy can obtain the ideal braking time and brake's braking torque.Therefore,the complex requirement of workover lifting system for operation process can be satisfied desirably.%汽车ABS防抱死刹车系统具有防滑防抱、制动相对距离短及能减轻轮胎磨损等优点.为此,将汽车ABS控制策略引入到钻(修)井机液压盘式刹车系统设计中,构建了具有手动/自动操作方式且能实现ABS控制策略的液压盘式刹车的新型液压控制系统,并对具有ABS系统与无ABS系统的盘式刹车分别进行液压系统与下入工况制动动力学仿真对比分析.分析结果表明,选择适当的ABS系统占空比,可以更接近无ABS系统刹车时间与角位移,并获得较好的压力调节波形,调整ABS控制策略可使系统获得理想的刹车时间与刹车制动力矩,从而能够较好地满足修井机起升系统作业过程的复杂要求.

  10. Application and Development of Carbon Brake Disc Materials for Commercial Aircraft%大型商用飞机炭刹车盘材料的应用进展

    Institute of Scientific and Technical Information of China (English)

    季光明

    2011-01-01

    From the 70 years of the 20th century(1970s), the research and application of carbon brake disc composite has experienced five generations. C/C composite material has become the first choice of carbon brake disc for corrmlercial aircraft and has been widely used in Airbus and Boeing because of its excellent features of light weight, good friction characteristics, long life and high heat-absorbing capacity. The domestic carbon brake material has made considerable development after several years of development, and has been used as PMA in B757 and A320. However, the further improvement of density uniformity, quality consistency of domestic carbon brake material, anti-oxidation coating reliabilit, and low cost technology is necessary.%炭刹车盘材料具有质量轻、摩擦特性好、使用寿命长、吸热能力高等一系列优良特性。从20世纪70年代问世以来,炭刹车盘复合材料的研制和应用总共经历了五代发展历程,已经成为商用飞机炭刹车副的首选材料,被广泛应用于空客和波音系列飞机。经过几十年的发展,国内炭刹车材料取得了长足的发展,已经作为PMA件应用于B757和A320机型,但仍需进一步提高国产炭刹车材料的密度均匀性、质量一致性、抗氧化涂层的可靠性及降低生产成本。

  11. 制动盘模态分析及其在生产线检测系统上的应用%Modal Analysis of Brake Disc and Its Application to Production-line Inspection System

    Institute of Scientific and Technical Information of China (English)

    褚志刚; 叶方标; 蒋忠翰; 张昌福; 周亚男

    2014-01-01

    为确定制动盘固有频率的容差范围,首先对其进行了试验模态分析和有限元模态分析,二者固有频率的误差小于2%,各对应阶次模态振型一致。在此基础上,利用有限元概率设计方法对影响制动盘固有频率的各结构设计变量进行了灵敏度分析,计算了制动盘固有频率的变化范围。结果表明,制动盘盘体直径、散热辐条宽度与高度、盘体内圈厚度、盘体外圈长度与厚度和沟槽深度等尺寸对低阶固有频率具有显著影响。表明有限元概率设计技术为在线检测系统各阶固有频率容差的设定提供了有效手段。%For determining the tolerance ranges of the natural frequencies of brake disc, firstly both experi-mental modal analysis and finite element modal analysis are conducted with relative errors of natural frequency re-sults less than 2% and the mode shapes of each corresponding order well coincide. On this basis, the sensitivities of natural frequency to the structural design variables of brake disc are analyzed by using finite element probability de-sign method with the natural frequency ranges of brake disc calculated. The results show that the disc diameter, the width and height of ventilated blades, the thickness of inner disc, the length and thickness of outer disc, and the groove depth have significant effects on lower-order natural frequencies. The finite element probability design tech-nique provides an effective means for the setting of tolerances of natural frequencies in online inspection system.

  12. 载荷形式对盘式制动器温度场分布的影响%Effects of load form on distribution of thermal ifeld on disc brake

    Institute of Scientific and Technical Information of China (English)

    王治军; 林尚飞; 陈淑琴

    2014-01-01

    分析了盘式制动器的产热机理及热量分配,利用ANSYS建立三维有限元模型,仿真得到恒定、渐变、正弦三种载荷形式下的制动盘温度场。结果表明,制动盘摩擦区域内节点温度呈锯齿状波动上升,沿制动盘轴向,距摩擦表面越远,温度越低,波动幅度越小;沿制动盘径向,不同半径处的节点温度不同,摩擦区域中间位置温度最高,存在较大的径向温度梯度;沿制动盘周向,随着制动时间的增加,温度分布趋于均匀;恒定载荷下,制动盘表面的温升最大,正弦载荷下的温升最小。%Thermogenesis mechanism and heat distribution of disc brake were analyzed, the 3-D finite element model was built with ANSYS and the thermal field of brake disc under constant load, graded load and sine load was got through simulation. The results show that temperature of node in friction region rise hackly, along axial of brake disc, the temperature and fluctuation range decrease with the increase of distance between node and friction surface;the temperature of nodes at different radius are distinguishing and it is highlighted at the middle of friction region ,so this causes radial temperature gradient; the temperature distribution along circumference is becoming uniform with time increase;temperature of brake disc surface under the constant load is the highest and which under the sine load is the lowest.

  13. 汽车车内制动噪声主动控制%Active Noise Control of Automotive Interior Braking Noise

    Institute of Scientific and Technical Information of China (English)

    冯天培; 孙跃东; 王岩松; 刘宁宁

    2016-01-01

    Low-frequency components of braking noise usually dominate the internal noise for some kinds of automobiles. Since the low-frequency noise has high energy, the strong interior noise will reduce the comfort for the passengers. In this paper, the braking noises at the driver’s ears in three different cars travelling at 60km/h in emergency braking were collected and analyzed in time-frequency domain. Results of analysis agreed well with the real ride-perception in a testing car. Then, the active braking noise control simulation using adaptive LMS algorithm was implemented. The results show that the low-frequency noise, especially in the range of 20 Hz-50 Hz, is greatly eliminated.%部分汽车制动时的车内噪声以低频成分占主导。低频噪声能量大,车内较强的低频制动噪声会给乘员带来不舒适的乘坐感受,降低车辆的乘坐舒适性。采集三辆轿车车内60 km/h紧急制动时司机位双耳处噪声信号并进行时-频域分析,分析结果与实车试验乘坐感受一致,接着运用低频噪声消噪效果较好的主动噪声控制方法,结合自适应LMS算法对样本信号进行消噪仿真实验,制动噪声低频部分得到较大的抑制,特别是在20 Hz~50 Hz低频带内,噪声能量衰减明显。

  14. Sistem Pendingin Paksa Anti Panas Lebih (Over Heating pada Rem Cakram (Disk Brake Kendaraan

    Directory of Open Access Journals (Sweden)

    Joni Dewanto

    2010-01-01

    Full Text Available Until now, the vehicle brakes are not usually equipped with a special cooling system, so that the release of heat into the air occurs naturally. When used continuously, the brakes can suffer damage as a result of the occurrence of over-heating. This condition is potentially causing a fatal accident. Physically, the over-heating often occurs in type disc brake, because the heat transfer surface is less proportionately, especially for high braking loads. This research aims to develop a brake disc with an active cooling system to prevent overheating. The system is applied to a simulated model of disc brakes empirically. The test was conducted at several levels of constant disc speed and breaking force. The results of this research indicate that at various braking load, the development of disc brakes with an active cooling system in the form of water vapor that is sprayed, can control the brake temperature rise and prevent over-heating.

  15. Modeling and Thermal Analysis of Disc

    OpenAIRE

    Brake Praveena S; Lava Kumar M

    2014-01-01

    The disc brake is a device used for slowing or stopping the rotation of the vehicle. Number of times using the brake for vehicle leads to heat generation during braking event, such that disc brake undergoes breakage due to high Temperature. Disc brake model is done by CATIA and analysis is done by using ANSYS workbench. The main purpose of this project is to study the Thermal analysis of the Materials for the Aluminum, Grey Cast Iron, HSS M42, and HSS M2. A comparison between ...

  16. 客车盘式制动器摩擦片前后磨损不均的分析%Analysis on Unbalanced Wear Between Front and Rear Brake Pads of Bus Disc Braker

    Institute of Scientific and Technical Information of China (English)

    汪桂金; 刘文虎; 孙克亮

    2015-01-01

    盘式制动器具有制动距离短、制动响应快、制动强度大、水稳定性强、散热性能好、结构紧凑、维修方便等优点,但在我国大中城市客车上的应用才刚刚开始。本文对城市客车前后桥采用盘式制动器造成的摩擦片磨损不均问题进行试验分析,找出问题原因,并提出相应的解决措施。%Disc brakers have the advantages of short braking distance, rapid response, excellent braking force, steady water performance, good heat distribution, compact installation and easy-to-repair, etc. Their applications on medium and large buses and coaches have just started in China. The authors mainly focus on the issue of unbalanced wear in braking pads between front and rear axles through testing analysis, and find out the main reasons, then state the corresponding solutions.

  17. Modification de la morphologie du graphite pour l'amélioration de la durée de vie des disques de frein poids lourd Graphite morphology modification for improvement of truck brake disc lifespan

    Directory of Open Access Journals (Sweden)

    Collignon M.

    2013-11-01

    Full Text Available La durée de vie des disques de frein pour applications poids lourds peut être limitée par une fissuration prématurée induite par les sollicitations thermomécaniques subies par le disque en condition de freinage. La présente étude propose une réponse matériau basée sur la modification de la morphologie du graphite. Le comportement des matériaux innovés est comparé en condition de freinage et de fatigue thermique à celui d'une fonte à graphite lamellaire utilisée en service. The truck brake disc lifespan can be limited by a premature failure induced by the thermo mechanical solicitations occurring during braking. This study proposes a solution by a material approach consisting in the modification of the graphite morphology. The behavior of evolved materials is tested under braking and thermal fatigue solicitations with comparison to an grey cast iron used in service.

  18. Analysis on Partial Friction Phenomenon of the Brake Disc for High-speed Train Brake%高速列车刹车片偏摩现象的研究

    Institute of Scientific and Technical Information of China (English)

    阎树田; 邹本涛; 高升

    2013-01-01

    Thermal structural coupled finite element method of brake pads for high speed train was given in this paper,calculate the boundary conditions, the finite element numerical simulation of brake pads was done by ABAQUS software and and make detailed analysis research of partial friction phenomenon for Brake pads.%研究了高速列车刹车片的热结构耦合有限元求解方法,确定其边界条件,利用ABAQUS软件对刹车片进行有限元数值模拟,并做了较为详细的分析研究,在此基础上分析了盘式制动器刹车片的偏摩现象.

  19. The Electronic Wedge Brake - EWB

    Energy Technology Data Exchange (ETDEWEB)

    Ho, L.M.; Roberts, R.P.; Hartmann, H.; Gombert, B. [Siemens VDO Automotive (Germany)

    2006-07-01

    Future driver assistance systems will not only monitor the current traffic situation, but actively assist the driver in the day to day driving routines and as well in emergency situations. Autonomous intervention in the vehicle behavior will help to keep the vehicle under control, even in hazardous situations. A fast and smart braking system is one of the basics for the next generation of driver assistance systems. Siemens VDO sees its electronic wedge brake (EWB) brake-by-wire technology as the answer to future vehicle chassis safety, weight, reliability and space requirements. Particularly in the automobile sector, there is an increasing trend towards replacing existing hydraulic or pneumatic brake systems with drive 'by-wire' solutions. While mechatronics, i.e. intelligent, controllable electromechanical actuators, are already in use in many automotive and non automotive areas, there are particularly strict requirements for purely electromechanical braking systems which require complex development processes. These are highly safety critical systems, which must provide both excellent control quality and sophisticated fail-safe behavior. The challenge is to achieve a high power density in the wheel brake actuators. (orig.)

  20. 基于VC++和ADAMS/Car的汽车制动性能仿真分析系统%Simulation and analysis of automotive braking system based on VC++ and ADAMS/Car

    Institute of Scientific and Technical Information of China (English)

    张杰; 孙虎; 杨波; 王斌

    2012-01-01

    To speed up the virtual development of the automobile braking system, VC++6.0 programming environment and the Junction of ADAMS are applied to execute the batch files based on the ADAMS/ CAR software,and the simulation and analysis system for automotive braking system is developed as well. Then a friendly convenient and the flexible man-machine conversation interface are developed by VC++ foreground.When the software is used,the user only is required to input the vehicle parameters and set the simulation parameters, which will be obtained from the backstage of the system and transformed to the ADAMS operating commands and encapsulated in acar.cmd file.ADAMS will automatically create a virtual model and simulate after executing the acar.cmd file, so that the data of the simulation is got.With the application of the system the modeling efficiency for virtual model is improved,which reduce the work load on study and design of braking system greatly.%为了提高汽车制动系统的虚拟研发速度,利用VC++6.0的编程环境和ADAMS可执行批处理文件的功能,以ADAMS/CAR软件为基础平台,开发了汽车制动性能仿真分析系统.通过VC++前台开发出友好、方便、易用的人机交互界面,用户在使用此软件时,只需在此界面中输入整车结构参数及仿真设置参数,系统在后台获取这些参数并转换为需要对ADAMS进行的操作命令后封装入acar.cmd文件中,ADAMS调用此文件后即可自动实现整车虚拟模型建立及计算仿真,并获取仿真试验数据.设计人员利用此系统,可提高虚拟模型的建模效率,大大减少汽车制动系统研究与设计的工作量.

  1. Simulation of the friction temperature field for mineral car's disc brake%矿车盘式制动器温度场的数值模拟

    Institute of Scientific and Technical Information of China (English)

    宋涛; 刘莹

    2014-01-01

    根据热分析理论,建立矿车盘式制动器摩擦副的有限元模型,模拟矿车制动过程的三维瞬态温度场,研究制动工况、制动时间对摩擦副温度的影响。研究结果表明,摩擦副温度场呈非轴对称分布,且轴向温度梯度较大;制动工况对温升速率和最大值影响显著;制动时间对温升过程有一定的影响。研究结果为制动器摩擦副热应力分析提供支持,进而为矿车盘式制动器工况提供技术数据,为改善制动器工作条件和改进制动器摩擦副的设计提供参考。%According to the heat analysis theory ,the kinetic model of the brake was established and its three-dimensional transient temperature field was simulated .The effect of braking condition and braking time on friction pairs'temperature were investigated . The results show that the temperature distribution in the brake is nonaxi-symmetric and possesses a sharper gradient in axial di-rections.Braking conditon plays an important role on the rising time and the maximum of temperature ,braking time has a certain influence on the rising process of temperature .The research results can offer support for the thermal stress analysis of the brake friction pair and can provide a technical data for the mineral car's actual braking condition .The research results can also improve the working condition of brake and provide a better structural design for the friction pairs of brake .

  2. Research on Coupled Extension Characteristic of Thermal Fatigue Cracks at Forged Brake Disc for High Speed Train%高速列车锻钢制动盘热疲劳裂纹耦合扩展特性研究

    Institute of Scientific and Technical Information of China (English)

    石晓玲; 李强; 宋占勋; 杨广雪

    2016-01-01

    据制动盘裂纹剖面的宏观形貌,发现盘面长裂纹的形成以多条半椭圆表面裂纹连通为主。针对制动盘在运行过程中的典型运用工况,采用有限元法计算制动盘在300 km/h紧急制动后的热应力,发现周向残余应力较大,并以此推测周向残余应力是驱动制动盘热疲劳裂纹扩展的主要原因。在此基础上,建立制动盘盘面的裂纹网格,研究了裂纹扩展过程中的应力强度因子和多裂纹耦合扩展规律。通过研究发现对于给定的载荷条件,不同初始形状比时,裂纹前缘应力强度因子的分布规律存在一定的规律性,随着裂纹的扩展,裂纹形状趋于扁平化;多裂纹扩展时,裂纹间距越小,裂纹间的相互作用越明显,扩展速度越快;但受制动盘结构和尺寸限制,共线裂纹数越多,每条裂纹扩展到临界值时的应力强度因子越小。%According to the profile of brake disc crack macro-morphology, the main forms of long crack are approximately its own expansion and multiple cracks connectivity. Regarding the brake disk typical conditions during operation, the circumferential residual stress are considerable by calculated the thermal stress in 300 km/h emergency braking using the finite element method. Thereafter, the thermal fatigue crack growth of brake disc is drove through circumferential residual stress. Based on the conclusion, the brake disc grid with crack is established, and then the distribution of the stress intensity factor and the coupled propagation law between multi-cracks in the crack propagation process are researched. The results show that, the stress intensity factor of crack tip have regularity for different initial crack size and the crack shape tends to flatten with crack propagation under same load; When multiple crack are propagated, crack spacing smaller, the faster expansion and the interaction are more obvious; however, considering the structure and

  3. Gravity brake

    Science.gov (United States)

    Lujan, Richard E.

    2001-01-01

    A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.

  4. 盘式制动器NVH性能的时-频域耦合仿真方法%Coupling Simulation Method for Disc Brake NVH Performance Evaluation in Time-frequency Domain

    Institute of Scientific and Technical Information of China (English)

    彭涛; 周亨; 田振勇

    2016-01-01

    汽车制动时的NVH性能对于乘车舒适性和防治环境噪声污染具有重要意义。目前常规的仿真方法为复特征值(CEA)法,通常CEA法比实际测试出现的制动尖叫频率点更多,容易造成误判。为此,提出采用时-频域耦合动态仿真方法对盘式制动器的NVH性能进行分析。基于有限元平台ABAQUS,根据国际噪声测试标准SAE J 2521规定的工况,分别采用CEA法和时-频域耦合仿真方法,对制动器的非稳态响应进行了分析,得到了制动器的加速度-频率响应曲线以及制动尖叫的频率点;将时-频域耦合仿真及CEA仿真结果与测试结果进行比较,结果表明:传统的CEA仿真得到的的尖叫频率值过多,相比之下时-频域耦合仿真得到的结果与测试数据更为吻合,能够更精准地预测制动器的尖叫噪声频率值。%During car braking, NVH performance is of great significance for ride comfort and environmental noise prevention. Currently, the conventional simulation method is the complex eigenvalue analysis (CEA) method. But this method usually gets more squeal frequencies than the test results which may cause misjudgments. So, the coupling dynamic simulation method in the time-frequency domain was brought up to analyze the NVH performance of disc brakes. Based on the finite element platform of ABAQUS, and according to the international noise test standard SAE J2521, both the CEA method and the implicit-explicit coupling simulation method were adopted to analyze the unsteady response of a disc brake. And the acceleration-frequency response curve of the brake and the frequency sampling points of the braking squeal were obtained. Both results from implicit-explicit coupling simulation and CEA method were compared with the test results. Results show that the CEA can get more squeal frequencies than the test results, but the results from time-frequency domain coupling method are in good agreement with the

  5. Thermal Analysis of Automotive Brake Disc%汽车制动器制动热应力及温度场分析

    Institute of Scientific and Technical Information of China (English)

    周鑫美; 杨蔓; 刘向征; 申苗; 奚源

    2014-01-01

    以热分析理论为基础,建立了汽车盘式制动器“热-固”耦合模型.在此基础上,模拟分析了循环制动工况下,制动盘的瞬态温度场分布及热应力结果,提出了制动盘的优化改进方向.

  6. 汽车高速盘制动的摩擦温度场及热应力分析%Friction Temperature Field and Thermal-stress Analysis of Auto Brake Disc at High Speed

    Institute of Scientific and Technical Information of China (English)

    韩宁; 赵河明; 王维

    2013-01-01

    The finite element software ABAQUS is used to analyze temperature variation of brake disc with the changing of fic-tion time and fiction speed, and the distribution of Mises stress at highest speed.The following conclusion are researched that brake disc heat dissipation is better at low speed, the temperature growth is linear with time.With the growth of speed, the high temperature ring narrow area occurres in the center of fiction, temperature range of strip near area and high temperature area are increasing.Mises stress in high temperature area is minimum, which means elastic modulus geting smaller with the increasing of temperature, the conclusion provides an theoretical basis for the study of new composite materials.%应用有限元软件ABAQUS分析刹车盘随摩擦时间、摩擦速度的温度变化情况及在转速最大时Mises 应力分布。得出如下结论:当低速时刹车盘的散热比较好,升温幅度与时间成线性关系;随着速度的增加在摩擦中心出现一条高温环形窄带,并且在条带附近区与高温区的温差也随速度随之增加;在高温区的Mises 应力最小,说明弹性模量也随温度增加在变小,分析结论为新型复合材料研究提供理论依据。

  7. Modeling and Thermal Analysis of Disc

    Directory of Open Access Journals (Sweden)

    Brake Praveena S

    2014-10-01

    Full Text Available The disc brake is a device used for slowing or stopping the rotation of the vehicle. Number of times using the brake for vehicle leads to heat generation during braking event, such that disc brake undergoes breakage due to high Temperature. Disc brake model is done by CATIA and analysis is done by using ANSYS workbench. The main purpose of this project is to study the Thermal analysis of the Materials for the Aluminum, Grey Cast Iron, HSS M42, and HSS M2. A comparison between the four materials for the Thermal values and material properties obtained from the Thermal analysis low thermal gradient material is preferred. Hence best suitable design, low thermal gradient material Grey cast iron is preferred for the Disc Brakes for better performance.

  8. 汽车制动器摩擦试验机测试系统的研究现状及展望%Research Status of Automotive Brake Friction Testing Machine Test System and Its Prospects

    Institute of Scientific and Technical Information of China (English)

    何晨; 梁军战

    2015-01-01

    汽车作为一种现代交通工具,其重要性毋庸置疑。随着汽车保有量的日益增多,汽车的安全问题引起了社会的广泛关注。介绍了汽车制动器摩擦试验机工作原理及特性,对其测试系统各种信号采集方式和数据存储方式的优缺点进行了总结及分析。为了解决目前信号采集误差大、数据不准确和系统稳定性不高等问题,结合汽车制动器摩擦试验机测试系统的研究现状,提出了诸多研究热点,可为汽车制动器摩擦试验机测试系统研究与开发提供参考。%Car is used as a modern transportation means its importance is beyond al doubt. Along with the steep increase of its own ̄ers,the problems of the cars’ s safety atlracts people's extra atlention. This paper not only introduces the working principle and char ̄acteristics of automotive brake friction testing machine ,but also does summarise and analyse the advantages and disadvantages of the signal acquisition method and data storage in the test system. Based on its research status,it puts forward many effective meas ̄ures to solve the problems,such as the wide error limit and low stability. The foundation is laid for its fest.

  9. Study on Braking Sensation Based on Urban Working Conditions

    Directory of Open Access Journals (Sweden)

    Abi Lanie

    2017-01-01

    Full Text Available In this paper we researched the vehicle braking sense in three aspects of human, vehicle and environment and analysed their impacts on brake feeling. Through the real vehicle test we analysed the relationship among pedal force, pedal travel and deceleration. We used dynamometer test method to study the brake noise question. We designed a fixture which could imitate the suspension and made the test more close to the true level. Moreover we discussed how to establish the evaluation system of vehicle braking condition. Through real vehicle test of braking, we can test and record the brake system parameters in the braking process under urban working conditions. We recorded the brake frequency, the change of brake speed and brake disc temperature. Meanwhile, based on the analysis of braking condition, we put forward the index of brake load to reflect the city’s traffic conditions. Experiment show that the braking condition and brake feel are related, braking condition also provides theoretical support for the design of brake system.

  10. Application of CAE analysis in NVH field for bus disc brake%CAE分析在客车盘式制动器NVH领域的应用

    Institute of Scientific and Technical Information of China (English)

    董良

    2012-01-01

    对制动噪声、制动抖动等盘式制动器常见的NVH故障现象及产生机理、影响因素、预防措施等进行研究,根据机理提出利用CAE分析在设计阶段对相关零部件进行确认,避免因零部件共振出现制动NVH问题,最后通过实例证明了CAE分析改进方法的有效性。%Research the common malfunction phenomeon of NBH for brake noise,brake shave and mechanism of generation,effection factors, preventive measures and etc,put forward to use CAD analysis to confirm the related components during design stage according to the mechanism.Avoid brake NVH issue caused by components resonance.Finally prove the effectiveness of CAE analysis improvement method through instance.

  11. Magnetostrictive Brake

    Science.gov (United States)

    Diftler, Myron A.; Hulse, Aaron

    2010-01-01

    A magnetostrictive brake has been designed as a more energy-efficient alternative to a magnetic fail-safe brake in a robot. (In the specific application, failsafe signifies that the brake is normally engaged; that is, power must be supplied to allow free rotation.) The magnetic failsafe brake must be supplied with about 8 W of electric power to initiate and maintain disengagement. In contrast, the magnetostrictive brake, which would have about the same dimensions and the same torque rating as those of the magnetic fail-safe brake, would demand only about 2 W of power for disengagement. The brake (see figure) would include a stationary base plate and a hub mounted on the base plate. Two solenoid assemblies would be mounted in diametrically opposed recesses in the hub. The cores of the solenoids would be made of the magnetostrictive alloy Terfenol-D or equivalent. The rotating part of the brake would be a ring-and spring- disk subassembly. By means of leaf springs not shown in the figure, this subassembly would be coupled with the shaft that the brake is meant to restrain. With no power supplied to the solenoids, a permanent magnet would pull axially on a stepped disk and on a shelf in the hub, causing the ring to be squeezed axially between the stepped disk and the hub. The friction associated with this axial squeeze would effect the braking action. Supplying electric power to the solenoids would cause the magnetostrictive cylinders to push radially inward against a set of wedges that would be in axial contact with the stepped disk. The wedges would convert the radial magnetostrictive strain to a multiplied axial displacement of the stepped disk. This axial displacement would be just large enough to lift the stepped disk, against the permanent magnetic force, out of contact with the ring. The ring would then be free to turn because it would no longer be squeezed axially between the stepped disk and the hub.

  12. Frictional Performance and Temperature Rise of a Mining Nonasbestos Brake Material during Emergency Braking

    Directory of Open Access Journals (Sweden)

    Jiusheng Bao

    2015-01-01

    Full Text Available By simulating emergency braking conditions of mine hoisters, tribological experiments of a mining nonasbestos brake material sliding on E355CC steel friction disc investigated a pad-on-disc friction tester. It is shown that, under combined influence of braking velocity and pressure, the lubricating film and micro-convex-apices on wear surface would have complex physicochemical reactions which make the instant friction coefficient rise gradually while the instant surface temperature rises first and then falls. With the antifriction effect from lubricating film and the desquamating of composite materials, the mean friction coefficient decreases first, then rises, and decreases again with the increasing of initial braking velocity. And with the existence of micro-convex-apices and variation from increment ratio of load and actual contacting area, it rises first and then falls with the increasing of braking pressure. However, the mean surface temperature rises obviously with the increasing of both initial braking velocity and braking pressure for growth of transformed kinetic energy. It is considered that the friction coefficient cannot be considered as a constant when designing brake devices for mine hoisters. And special attention should be paid to the serious influence of surface temperature on tribological performance of brake material during emergency braking.

  13. OPTIMIZATION DESIGN ON VENTILATED DISC BRAKE BASED ON SURROGARTE MODEL TECHNOLOGY%基于代理模型的通风盘式制动器制动盘结构优化设计

    Institute of Scientific and Technical Information of China (English)

    曲杰; 苏海赋

    2013-01-01

    该文提出一种基于代理模型的复杂结构优化设计方法,并用于通风盘式制动器制动盘结构优化设计.提出的优化设计方法集成了CAE分析、实验设计、代理模型构造及非线性优化几部分,实验设计采用拉丁超立方抽样策略,代理模型选用改进的响应面模型,非线性优化算法采用序列二次规划算法.为了解决传统的响应面模型部分预测值与实验值误差较大问题,改进方法认为只有能够确保在每一个抽样点处的预测值与试验值的相对误差均在一定范围内的响应面模型才是一个可行的模型.在保证制动盘质量不变情况下,以寿命最大化为目标,应用设计的集成优化方法对制动盘进行优化设计,优化设计结果较好,其中制动盘疲劳寿命根据Coffin-Manson方法预测,制动过程中制动盘表面最大热应力及最高温度通过热机耦合的有限元模拟紧急制动过程获得.优化结果表明该文提出的方法是一种有效的复杂结构的优化设计方法.%Based on the surrogate model technology, this paper proposes an optimization design method on the complex structure, and the method is applied to the optimization design on the ventilated disc brake. The proposed method integrates the CAE analysis, experimental design, construction of the surrogate model and the nonlinear optimization. Expermental design adopts the Latin hypercube sampling stragety, the surrogate model adopts the improved response surface methodology and the optimization algorithm applies the sequential quadratic programming algorithm. However, there is a problem that the differences between the predicted values and experimental values for some sampled points are relative large in the traditional response surface methodology; in the improved method, it is assumed that the model is feasible only if the relative error between the predicted value and the experimental value is within a margin (e) at each sampled point

  14. NAC Off-Vehicle Brake Testing Project

    Science.gov (United States)

    2007-05-01

    Project Officer ( TIPO ) US Army National Automotive Center (NAC) Warren, MI Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden...May 2007 FinalR1 UNCLAS: Dist A. Approved for public release Leo Miller, Technology Insertion Project Officer ( TIPO ) NAC Off-vehicle Brake Testing

  15. 制动防抱死工况制动器热机耦合特性仿真分析%Computational Investigation into Thermal-mechanical Coupling Characteristics of Disc Brake under Anti-lock Braking Condition

    Institute of Scientific and Technical Information of China (English)

    张立军; 何臻; 孟德建

    2016-01-01

    制动工况对制动器的热机耦合特性具有重要影响.建立了三自由度汽车制动动力学模型,制动力由采用滑移率逻辑门限值控制策略的制动防抱死系统(ABS,Anti-lock Brake System)控制,对干路面和湿路面的制动防抱死工况仿真,同时对相应路面非制动防抱死工况仿真,用于比较分析;建立通风盘式制动器热机耦合有限元动力学模型,对不同制动工况制动盘和制动块的热机耦合特性进行仿真,分析了制动防抱死工况制动器热机耦合特性,并通过与非制动防抱死工况比较,探究ABS对制动器热机耦合特性影响.经分析发现,制动防抱死系统引起的制动压力变化以及制动摩擦热功率改变将对热机耦合特性各个指标产生影响.

  16. Structure Topology Optimization of Brake Pad in Large- megawatt Wind Turbine Brake Considering Thermal- structural Coupling

    Science.gov (United States)

    Zhang, S. F.; Yin, J.; Liu, Y.; Sha, Z. H.; Ma, F. J.

    2016-11-01

    There always exists severe non-uniform wear of brake pad in large-megawatt wind turbine brake during the braking process, which has the brake pad worn out in advance and even threats the safety production of wind turbine. The root cause of this phenomenon is the non-uniform deformation caused by thermal-structural coupling effect between brake pad and disc while braking under the conditions of both high speed and heavy load. For this problem, mathematical model of thermal-structural coupling analysis is built. Based on the topology optimization method of Solid Isotropic Microstructures with Penalization, SIMP, structure topology optimization of brake pad is developed considering the deformation caused by thermal-structural coupling effect. The objective function is the minimum flexibility, and the structure topology optimization model of brake pad is established after indirect thermal- structural coupling analysis. Compared with the optimization result considering non-thermal- structural coupling, the conspicuous influence of thermal effect on brake pad wear and deformation is proven as well as the rationality of taking thermal-structural coupling effect as optimization condition. Reconstructed model is built according to the result, meanwhile analysis for verification is carried out with the same working condition. This study provides theoretical foundation for the design of high-speed and heavy-load brake pad. The new structure may provide design reference for improving the stress condition between brake pad and disc, enhancing the use ratio of friction material and increasing the working performance of large-megawatt wind turbine brake.

  17. Low-impact friction materials for brake pads

    OpenAIRE

    2016-01-01

    State-of-the-art friction materials for applications in disc brake systems are constituted by composite materials, specifically formulated to ensure proper friction and wear performances, under the sliding contact conditions of braking events. The bases of typical friction compound formulations usually include 10 to 30 different components bonded with a polymeric binder cross-linked in situ. Main requests to be fulfilled during braking are an adequate friction efficiency and enough mechanical...

  18. 动态摩擦因数对蝶式制动器温度场影响的试验和模拟研究%Experimental and Simulation Research on the Influence of Dynamic Friction Coefficient to the Temperature Field of Disc Brake

    Institute of Scientific and Technical Information of China (English)

    周俊峰; 王伟; 张晨; 刘焜

    2016-01-01

    To research into temperature field of disc brake, as needed, a constant speed braking bench is developed to simulate the braking condition of motorcycle under long slope by similarity principle. The disc fixed on rotating shaft, which is clamped by three jaw chuck of lathe, rotate with constant speed. The disc is clamped by inner pad and outward pad though hydraulic pressure. Temperature evolution of certain point on outward pad, braking torque evolution, mean value of braking pressure, temperature evolution on the frictional area of disc are measured by thermal couple, pressure sensor, piezometer, thermal imager respectively. The braking bench could realize the dynamic test of all variables under different rational speed and different braking pressure. The maximum temperature is chosen as variable to research the evolution of friction coefficient with temperature increasing. Based on experiment, simulation and analysis are did by ABAQUS. Simulation models are made from actual model by the ratio 1:1, load and boundary conditions are the same as reality, the evolution of friction coefficient with increasing temperature is put into contact condition, finally, the evolutions of the temperature fields of disc and pad are obtained. Compare to the simulation result and experimental result, it shows that the contact model with dynamic friction coefficient is better fit into the actual braking condition.%针对蝶式制动器制动过程中温度场研究的需要,利用相似原理研制定速制动试验台,用以模拟摩托车匀速下长坡时的制动工况。制动试验台用车床的三爪卡盘控制固定在旋转轴上的制动盘做定速旋转运动,内外摩擦片通过液压力夹紧制动盘,使制动盘与摩擦片发生摩擦运动,通过热电偶、拉压力传感器、压力表、热成像仪分别测出定速制动50 s的摩擦片上固定点的温度变化、制动扭矩(经计算得出)的动态变化、制动力的均值、制动盘摩

  19. 基于瞬态分析法的轮盘制动系统摩擦自激振动研究%Study on Friction-induced Self-excited Vibration of a Wheel-disc Brake System Using Transient Analysis Method

    Institute of Scientific and Technical Information of China (English)

    黄盼盼; 陈光雄; 莫继良

    2014-01-01

    There are two analysis methodologies available for predicting brake squeal using the finite element method, namely,complex eigenvalue analysis method and dynamic transient analysis method. Not all the unstable frequency ob-tained using complex eigenvalue analysis method can be observed in experiments,while transient analysis method is able to predict real unstable frequency in theory. A transient dynamic model of a wheel-disc brake system of EMU was estab-lished to study friction-induced self-excited vibration of the brake system,in which the friction coupling between brake pads and disc was imposed. Results show that the value of the dominant vibration frequency of the contact force between the brake pad and disc is consistent with that of the normal vibration of the brake pad. The dominant vibration frequency obtained by the transient analysis method is very close to the value of the unstable frequency obtained by the complex ei-genvalue method.%在制动噪声的有限元分析方法中,复特征值方法预测得到的不稳定频率过于保守,而瞬态分析方法在理论上可以得到较为真实的不稳定频率。考虑制动闸片与制动盘接触点间的摩擦力耦合作用,基于建立的高速动车轮盘制动系统的有限元模型,采用瞬态分析法对高速动车轮盘制动系统进行摩擦自激振动分析,并与复特征值分析法得到结果的进行比较。结果表明,接触面间法向接触力的振动主频与闸片法向振动的主频一致;制动系统瞬态动力学分析得到的振动主频与其复特征值分析得到的不稳定频率基本相符。

  20. XJ250修井机液压盘式刹车液压控制系统仿真分析%Simulation Analysis of the Hydraulic Control System of the Hydraulic Disc Brake on the X J250 Workover Rig

    Institute of Scientific and Technical Information of China (English)

    张连业; 吴文秀; 刘威

    2012-01-01

    Taking as the object of study the hydraulic control system of the hydraulic disc brake on the XJ250 workover rig, the mathematical model on the basis of global flow and hydraulic cylinder piston motion equation was established by analyzing the structure of the control system. The AMESim simulation model for the hydraulic control system of the braking system was constructed and the model parameters and simulation parameters were set. The var- iation of the typical sine curve hydraulic source signal and excitation electromagnetic valve signal was used to carry out a simulation study of the response system of the operating brake hydraulic control system. The sudden opening of the step switch signal was used to conduct a simulation analysis of the urgency brake hydraulic system response. The hydraulic dynamic response curve of the main valve port of the hydraulic control system in the process of operating brake and urgency brake was derived. The simulation result is in agreement with the practical operation. The simulation analysis offers a reference for the improvement of the performance of the hydraulic control system of the workover rig disc brake.%以XJ250修井机液压盘式刹车的液压控制系统为研究对象,通过分析液压盘式刹车的液压控制系统结构,建立了基于全局流量与液压缸活塞运动方程的数学模型;构建了液压控制系统的AMESim仿真模型,设置了模型参数及仿真参数。以典型的正弦曲线液压源信号及激励电磁阀信号变化仿真研究工作制动液压控制系统响应性能,以阶跃开关信号突然开启模拟分析紧急制动液压系统响应。得到了工作制动及紧急制动过程中液压控制系统主要阀口处液压动态响应曲线,仿真结果与实际运行情况相符。该仿真分析为修井机液压盘式刹车液压控制系统性能的改进与完善提供了参考。

  1. 湿式制动器摩擦盘表面温度场的瞬态分析%The transient analysis of friction-disc surface temperature field on the wet multiple-disc brake

    Institute of Scientific and Technical Information of China (English)

    苑仁飞; 孟宪皆

    2015-01-01

    首先,运用微元功率法得出了摩擦副间的热流密度,依据半无限大物体的瞬态热分析建立了瞬态导热微分方程,利用有限时间单元法求解摩擦盘表面温度场的瞬态值,得到摩擦盘表面温度场的数学模型;其次,以某一款重型汽车为研究对象,利用所建立的摩擦盘表面温度场的数学模型,得到其瞬态温度场的分布;最后,运用 ANSYS 软件进行仿真试验,把前述计算结果与 ANSYS 仿真试验结果进行对比,检验了模型的有效性和可靠性。%Firstly,we established the mathematical model of the friction-disc surface temperature field,which using the infinitesimal power method to get the mathematical model of heat flux a-mong the friction pair,establishing the transient heat conduction differential equation on the basis of transient thermal analysis of half infinite object,and using the finite time element method to solve the transient value of friction-disc surface temperature field.Secondly,taking a heavy vehi-cle as the object of research,and using the mathematical model of friction-disc surface tempera-ture field,we got the distribution of transient temperature field.Finally,using the ANSYS soft-ware,the simulation experiment was carried out,and the validity and reliability of model through the contrast of calculation results and ANSYS simulation experiment results were proved.

  2. Pad-mode-induced instantaneous mode instability for simple models of brake systems

    Science.gov (United States)

    Oberst, S.; Lai, J. C. S.

    2015-10-01

    Automotive disc brake squeal is fugitive, transient and remains difficult to predict. In particular, instantaneous mode squeal observed experimentally does not seem to be associated with mode coupling and its mechanism is not clear. The effects of contact pressures, friction coefficients as well as material properties (pressure and temperature dependency and anisotropy) for brake squeal propensity have not been systematically explored. By analysing a finite element model of an isotropic pad sliding on a plate similar to that of a previously reported experimental study, pad modes have been identified and found to be stable using conventional complex eigenvalue analysis. However, by subjecting the model to contact pressure harmonic excitation for a range of pressures and friction coefficients, a forced response analysis reveals that the dissipated energy for pad modes is negative and becomes more negative with increasing contact pressures and friction coefficients, indicating the potential for instabilities. The frequency of the pad mode in the sliding direction is within the range of squeal frequencies observed experimentally. Nonlinear time series analysis of the vibration velocity also confirms the evolution of instabilities induced by pad modes as the friction coefficient increases. By extending this analysis to a more realistic but simple brake model in the form of a pad-on-disc system, in-plane pad-modes, which a complex eigenvalue analysis predicts to be stable, have also been identified by negative dissipated energy for both isotropic and anisotropic pad material properties. The influence of contact pressures on potential instabilities has been found to be more dominant than changes in material properties owing to changes in pressure or temperature. Results here suggest that instantaneous mode squeal is likely caused by in-plane pad-mode instabilities.

  3. Evaluation of Wear in Aftermarket Brake Pads for Enhancing Braking Performance in a Passenger Vehicle

    Directory of Open Access Journals (Sweden)

    Mohd Zaki Bahrom

    2016-08-01

    Full Text Available Nowadays, due to the high demands from the independence automotive service centers; there are many aftermarket brake pads available at spare parts shops and sold at reasonable prices. Several types of brake pads are available in the market such as semi-metallic and Non-Asbestos brake pads. The purpose of this study is to evaluate the wear of after-market brake pad performance under the normal driving conditions (highway and non-highway. Three types of aftermarket brake pads that mainly used and sold by independent service shop were selected in this study.  The data of the wear in thicknesses losses and weight percentage losses were recorded. The results show that brake pad of non- Asbestos Organic type gives the highest wear loss and create a lot of dust. For semi-metallic brake pad type, the result shows the lowest mass loss. Therefore, it is important to select the suitable type of after-market brake pads in order to get balance between cost and quality.

  4. Optical classification for quality and defect analysis of train brakes

    Science.gov (United States)

    Glock, Stefan; Hausmann, Stefan; Gerke, Sebastian; Warok, Alexander; Spiess, Peter; Witte, Stefan; Lohweg, Volker

    2009-06-01

    In this paper we present an optical measurement system approach for quality analysis of brakes which are used in high-speed trains. The brakes consist of the so called brake discs and pads. In a deceleration process the discs will be heated up to 500°C. The quality measure is based on the fact that the heated brake discs should not generate hot spots inside the brake material. Instead, the brake disc should be heated homogeneously by the deceleration. Therefore, it makes sense to analyze the number of hot spots and their relative gradients to create a quality measure for train brakes. In this contribution we present a new approach for a quality measurement system which is based on an image analysis and classification of infra-red based heat images. Brake images which are represented in pseudo-color are first transformed in a linear grayscale space by a hue-saturation-intensity (HSI) space. This transform is necessary for the following gradient analysis which is based on gray scale gradient filters. Furthermore, different features based on Haralick's measures are generated from the gray scale and gradient images. A following Fuzzy-Pattern-Classifier is used for the classification of good and bad brakes. It has to be pointed out that the classifier returns a score value for each brake which is between 0 and 100% good quality. This fact guarantees that not only good and bad bakes can be distinguished, but also their quality can be labeled. The results show that all critical thermal patterns of train brakes can be sensed and verified.

  5. Numerical simulation for die forging of high-speed railway brake disc hub%高速列车制动盘盘毂锻造工艺数值模拟

    Institute of Scientific and Technical Information of China (English)

    张龙; 孙明月; 李殿中

    2012-01-01

    基于实测的40CrA钢高温应力-应变曲线和热物性参数,建立了高速列车制动盘盘毂毛坯在模锻过程的有限元模型.运用DEFORM-3D软件,对该盘毂的多步骤锻造过程进行热力耦合模拟,得到了应力、应变和温度随时间的变化规律;研究盘毂成形过程的金属流动机制,模拟了产生折叠缺陷的位置;预测了盘毂完全成形所需的锻锤打击次数;对终锻模具的最大主应力进行分析,预测了模具在实际生产中可能产生的塌陷、开裂缺陷及其位置.根据模拟结果进行了生产试制,验证了工艺的可行性和模拟的准确性.%Based on the measured stress-strain curves at different strain rates and the thermal-physical parameters of 40CrA steel, the finite element model for the forging process of a high-speed railway brake disc hub was established. The thermal-mechanical coupling process was simulated by using DEFORM-3D code. From the simulation results, the strain, stress and temperature field in the forging process were obtained. In order to simulate the folding defect position, the mechanism of metal flow of the disc hub was investigated. Furthermore, the number of combating for forging hammer was predicted. By analyzing the maximum principal stress on the final-forging mold, the collapse and crack that might arise in the actual production were predicted. The experimental results verified the feasibility of the process and the accuracy of the simulation.

  6. Optimal design and selection of magneto-rheological brake types based on braking torque and mass

    Science.gov (United States)

    Nguyen, Q. H.; Lang, V. T.; Choi, S. B.

    2015-06-01

    In developing magnetorheological brakes (MRBs), it is well known that the braking torque and the mass of the MRBs are important factors that should be considered in the product’s design. This research focuses on the optimal design of different types of MRBs, from which we identify an optimal selection of MRB types, considering braking torque and mass. In the optimization, common types of MRBs such as disc-type, drum-type, hybrid-type, and T-shape types are considered. The optimization problem is to find an optimal MRB structure that can produce the required braking torque while minimizing its mass. After a brief description of the configuration of the MRBs, the MRBs’ braking torque is derived based on the Herschel-Bulkley rheological model of the magnetorheological fluid. Then, the optimal designs of the MRBs are analyzed. The optimization objective is to minimize the mass of the brake while the braking torque is constrained to be greater than a required value. In addition, the power consumption of the MRBs is also considered as a reference parameter in the optimization. A finite element analysis integrated with an optimization tool is used to obtain optimal solutions for the MRBs. Optimal solutions of MRBs with different required braking torque values are obtained based on the proposed optimization procedure. From the results, we discuss the optimal selection of MRB types, considering braking torque and mass.

  7. Wear Modalities and Mechanisms of the Mining Non-asbestos Composite Brake Material

    Science.gov (United States)

    Bao, Jiusheng; Yin, Yan; Zhu, Zhencai; Tong, Minming; Lu, Yuhao; Peng, Yuxing

    2013-08-01

    The mining brake material is generally made of composite materials and its wear has important influences on the braking performance of disc brakes. In order to improve the braking reliability of mine hoisters, this paper did some tribological investigations on the mining brake material to reveal its wear modalities and mechanisms. The mining non-asbestos brake shoe and 16Mn steel were selected as braking pairs and tested on a pad-on-disc friction tester. And a SEM was used to observe the worn surface of the brake shoe. It is shown that the non-asbestos brake material has mainly five wear modalities: adhesive wear, abrasive wear, cutting wear, fatigue wear and high heat wear. At the front period of a single braking the wear modality is mainly composed of some light mechanical wear such as abrasive, cutting and point adhesive. With the temperature rising at the back period it transforms to some heavy mechanical wear such as piece adhesive and fatigue. While in several repeated brakings once the surface temperature rises beyond the thermal-decomposition point of the bonding material, the strong destructive high heat wear takes leading roles on the surface. And a phenomenon called friction catastrophe (FC) occurs easily, which as a result causes a braking failure. It is considered that the friction heat has important influences on the wear modalities of the brake material. And the reduction of friction heat must be an effective technical method for decreasing wear and avoiding braking failures.

  8. THE INFLUENCE OF BRAKE PADS THERMAL CONDUCTIVITY ON PASSANGER CAR BRAKE SYSTEM EFFICIENCY

    Directory of Open Access Journals (Sweden)

    Predrag D Milenković

    2010-01-01

    Full Text Available In phase of vehicle braking system designing, besides of mechanical characteristics, it is also necessary to take under consideration the system's thermal features. This is because it is not enough just to achieve proper braking power, for the brake system to be effective but equally important thing is the dissipation of heat to the environment. Heat developed in the friction surfaces dissipate into the environment over the disk in one hand and through the brake linings and caliper, in the other. The striving is to make that greatest amount of heat to dissipate not threw the brake pads but threw disc. The experimental researching of heat transfer process taking place at vehicle brakes was made in the R&D Center of "Zastava automobili" car factory in order to increase the efficiency of brake system. The standard laboratory and road test procedures were used, according to factory quality regulations. The modern equipment such as thermo camera, thermo couples, torque transducers, signal amplifiers, optical speed measuring system and laptop computer were used. In this paper will be shown the part of the experimental researching, which refers to the thermal conductivity of brake pad friction linings.

  9. Emergency braking : research summary.

    NARCIS (Netherlands)

    Schlösser, L.H.M.

    1976-01-01

    This report deals with an investigation concerning braking capacity of trucks if somewhere a failure occurs in the normal service brake. Purpose of research was to get an insight in various secondary braking systems for trucks. It is shown that with almost all of the secondary braking system it was

  10. Bicycle Braking System

    OpenAIRE

    Brady, Noel

    2001-01-01

    A bicycle braking system for permitting controlled rotation and continuous power to the wheels of a bicycle during braking of the bicycle to enhance control of the bicycle during braking includes a cylindrical brake pad that is spring loaded within angled slots in a casing. The brake pad is positioned proximate the rim of a wheel and a cable assembly is coupled to the brake pad for urging the brake pad towards an end of the angled slots and against the rim of the wheel to slow rotation of the...

  11. State Articulated Instructional Objectives Guide for Occupational Education Programs. State Pilot Model for Automotive Mechanics (DCC V-003) and Automotive Mechanics (High School).

    Science.gov (United States)

    North Carolina State Dept. of Community Colleges, Raleigh.

    This articulation instructional objective guide for automotive mechanics contains summary information on fifteen blocks (courses) of instruction. They are introduction to automotive technology; lubrication and vehicle operating maintenance; cooling system maintenance and repair; automobile heater maintenance and repair; braking system maintenance…

  12. How to play a disc brake

    CERN Document Server

    Kirillov, Oleg N

    2007-01-01

    We consider a gyroscopic system under the action of small dissipative and non-conservative positional forces, which has its origin in the models of rotating bodies of revolution being in frictional contact. The spectrum of the unperturbed gyroscopic system forms a "spectral mesh" in the plane "frequency -gyroscopic parameter" with double semi-simple purely imaginary eigenvalues at zero value of the gyroscopic parameter. It is shown that dissipative forces lead to the splitting of the semi-simple eigenvalue with the creation of the so-called "bubble of instability" - a ring in the three-dimensional space of the gyroscopic parameter and real and imaginary parts of eigenvalues, which corresponds to complex eigenvalues. In case of full dissipation with a positive-definite damping matrix the eigenvalues of the ring have negative real parts making the bubble a latent source of instability because it can "emerge" to the region of eigenvalues with positive real parts due to action of both indefinite damping and non-c...

  13. Can non-ideal magnetohydrodynamics solve the magnetic braking catastrophe?

    CERN Document Server

    Wurster, James; Bate, Matthew R

    2015-01-01

    We investigate whether or not the low ionisation fractions in molecular cloud cores can solve the `magnetic braking catastrophe', where magnetic fields prevent the formation of circumstellar discs around young stars. We perform three-dimensional smoothed particle non-ideal magnetohydrodynamics (MHD) simulations of the gravitational collapse of one solar mass molecular cloud cores, incorporating the effects of ambipolar diffusion, Ohmic resistivity and the Hall effect alongside a self-consistent calculation of the ionisation chemistry assuming 0.1 micron grains. When including only ambipolar diffusion or Ohmic resistivity, discs do not form in the presence of strong magnetic fields, similar to the cases using ideal MHD. With the Hall effect included, disc formation depends on the direction of the magnetic field with respect to the rotation vector of the gas cloud. When the vectors are aligned, strong magnetic braking occurs and no disc is formed. When the vectors are anti-aligned, a disc with radius of 13AU ca...

  14. 盘式制动器热应力磨损耦合行为的数值模拟%Numerical Simulation on the Coupling Behavior Between Thermal Load, Contact Stress and Wear in a Disc Brake

    Institute of Scientific and Technical Information of China (English)

    张方宇; 桂良进; 范子杰

    2014-01-01

    本文中探讨了盘式制动器制动过程中摩擦片和制动盘之间的热负荷接触应力磨损耦合行为的数值模拟方法。首先建立了盘式制动器的有限元模型;然后研究了应力磨损耦合分析的数值计算方法,并且模拟了摩擦片和制动盘的磨合过程;最后分别对热应力耦合条件下和紧急制动工况下的摩擦片磨损行为进行了模拟。结果表明,所提出的模拟方法是有效的。%The numerical simulation method of thermal load,contact stress and wear coupling behavior be-tween the pad and disk of disk brake during braking process is investigated in this paper. Firstly the finite element model for disk brake is built. Then the numerical calculation method of stress-wear coupling analysis is studied and the running-in process between pad and disk is simulated. Finally the wear behavior of brake pad in both stress-wear coupling and emergency braking conditions are simulated respectively. The results show that the simulation method proposed is effective.

  15. 盘式制动器

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Analysis of automotive disc brake cooling characteristics; Application of the empirical mode decomposition method to the identification of disc brake squeal;Aspects of disc brake judder;Brake squeal analysis incorporating contact conditions and other nonlinear effects;Characteristics of wear particles produced during fi'iction tests of conventional and unconventional disc brake materials……

  16. Safety Braking System

    Directory of Open Access Journals (Sweden)

    Joseph Charles

    2016-10-01

    Full Text Available Now a day's accidents due to brake failure are increasing in a high margin, so safety has acquired a greater priority. In order to control this sudden brake failures we have modified the conventional braking systems in automobiles by adding an extra safety brake to the engine shaft. The idea of the work is to improve the safety parameters regarding the brakes. Engagement of the secondary brake without the assistance of driver is an advantage for this system. As it would make the vehicle to stop without any lag. A Hall effect sensor is used to detect the motion of wheel by noting the magnetic field. The signals given out from the sensor directs the microcontroller to operate the relay and hence to actuate the solenoid and thereby actuating the secondary brake.

  17. The effects of porosity in friction performance of brake pad using waste tire dust

    Directory of Open Access Journals (Sweden)

    İbrahim Mutlu

    2015-10-01

    Full Text Available Abstract This research is focused on the effect of porosity on the friction-wear properties of automotive brake pads. Waste Tire Dust (WTD was used as a new friction material in brake pads. Newly formulated brake pad materials with five different components have been produced by conventional techniques. In the experimental studies, the change of the friction coefficient, the temperature of the friction surface, the specific wear rate, and the hardness, density and porosity were measured. In addition, the micro-structural characterizations of brake pads are determined using Scanning Electron Microscopy (SEM. The mean coefficient of friction, porosity and specific wear are increased due to a WTD rate increases, on the other hand, hardness and density are decreased. As a result, WTD can be considered as an alternative to revalorize this kind of waste products in the brake pads and the amount of porosity of the brake pad affected the friction coefficient and wear behavior of the pad.

  18. Automotive sensors

    Science.gov (United States)

    Marek, Jiri; Illing, Matthias

    2003-01-01

    Sensors are an essential component of most electronic systems in the car. They deliver input parameters for comfort features, engine and emission control as well as for the active and passive safety systems. New technologies such as silicon micromachining play an important role for the introduction of these sensors in all vehicle classes. The importance and use of these sensor technologies in today"s automotive applications will be shown in this article. Finally an outlook on important current developments and new functions in the car will be given.

  19. Muzzle brakes and their performance

    Directory of Open Access Journals (Sweden)

    J. P. Sirpal

    1958-01-01

    Full Text Available A criteria for the usefulness of a muzzle brake on any equipment is discussed and applied to existing weapons. Efficiencies of the existing muzzle brakes are also calculated. Design considerations for a muzzle brake are summarized.

  20. 基于ANSYS汽车盘式制动器温度场和热应力数值模拟%Simulation of the Temperature Field and Thermal Stress for Automotive Disc Brake Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    刘莹; 胡育勇; 任奇锋; 曹霜霜; 宋涛

    2013-01-01

    基于ANSYS建立了某汽车盘式制动器三维实体模型,分析了不同制动工况下盘式制动器的温度场和热应力,还分析了离心力与压应力和摩擦切应力分别作用下的应力分布.结果表明:热应力远大于其他应力的作用,这在分析盘式制动器失效时起着主导作用.运用循环迭代法进行温度场模拟,分析显示摩擦区温度是震荡上升、存在明显的尾迹且其显著大于非摩擦区温度.采用间接耦合法将温度场结果作为应力场载荷分析的热应力,结果显示:热应力呈现交变应力状态且幅值较大,摩擦区周向应力明显大于径向应力,制动盘凸台连接处应力很大.

  1. 汽车盘制动器优化设计热和机械特性的研究(二)%A Study of Thermal And Mechanical Behaviour For the Design of Automotive Disc Brakes

    Institute of Scientific and Technical Information of China (English)

    H-JCho; C-D Cho

    2011-01-01

    由于热量集中于制动盘的表面造成热弹不稳定性(TEI)而引起热变形.这样可能发生大家知道的低频强烈振动.因为在盘和衬块的接触面间的摩擦系数变化,在摩擦衬块发生尖叫声.通过对热聚集和尖叫现象的联合分析,对高热和机械特性可设计一最佳的盘和摩擦衬块.本文同时考虑了热和机械不稳定性按照盘的厚度,卡钳的加压方式,衬片弧长进行了数值和实验分析.采用有限元分析法(FEA)计算了热变形和压力分布.采用汽车底盘测功器和高速红外摄像仪进行实验评估TEI性能,结果用FEA修正.采用FEA估计机械不稳定性进行复杂固有值分析,按照转子和摩擦衬盘的形状对于一固有值问题应用修正仿真结果分析接合形式.在热聚集和尖叫问题期间,讨论因考虑盘制动器性能盘和摩擦衬块的设计.

  2. A Study of Thermal And Mechanical Behaviour For the Design of Automotive Disc Brakes%汽车盘制动器优化设计热和机械特性的研究(一)

    Institute of Scientific and Technical Information of China (English)

    H-J Cho; C-D Cho

    2011-01-01

    由于热量集中于制动盘的表面造成热弹不稳定性(TEI)而引起热变形.这样可能发生大家知道的低频强烈振动.因为在盘和衬块的接触面间的摩擦系数变化,在摩擦衬决发生尖叫声.通过对热聚集和尖叫现象的联合分析,对高热和机械特性可设计一最佳的盘和摩擦衬块.本文同时考虑了热和机械不稳定性按照盘的厚度,卡钳的加压方式,衬片弧长进行了数值和实验分析.采用有限元分析法(FEA)计算了热变形和压力分布.采用汽车底盘测功器和高速红外摄像仪进行实验评估TEI性能,结果用FEA修正.采用FEA估计机械不稳定性进行复杂固有值分析,按照转子和摩擦衬盘的形状对于一固有值问题应用修正仿真结果分析接合形式.在热聚集和尖叫问题期间,讨论因考虑盘制动器性能盘和摩擦衬块的设计.

  3. Morphology and properties of periwinkle shell asbestos-free brake pad

    OpenAIRE

    D.S. Yawas; S.Y.Aku; S.G. Amaren

    2016-01-01

    The development of asbestos-free automotive brake pad using periwinkle shell particles as frictional filler material is presented. This was with a view to exploiting the characteristics of the periwinkle shell, which is largely deposited as a waste, in replacing asbestos which has been found to be carcinogenic. Five sets of brake pads with different sieve size (710–125 μm) of periwinkle shell particles with 35% resin were produced using compressive moulding. The physical, mechanical and tribo...

  4. 14 CFR 25.735 - Brakes and braking systems.

    Science.gov (United States)

    2010-01-01

    ... (ii) Allow the pilot(s) to override the system by use of manual braking. (d) Parking brake. The airplane must have a parking brake control that, when selected on, will, without further attention, prevent... be indication in the cockpit when the parking brake is not fully released. (e) Antiskid system. If...

  5. Improved Electromagnetic Brake

    Science.gov (United States)

    Martin, Toby B.

    2004-01-01

    A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may

  6. Braking System for Wind Turbines

    Science.gov (United States)

    Krysiak, J. E.; Webb, F. E.

    1987-01-01

    Operating turbine stopped smoothly by fail-safe mechanism. Windturbine braking systems improved by system consisting of two large steel-alloy disks mounted on high-speed shaft of gear box, and brakepad assembly mounted on bracket fastened to top of gear box. Lever arms (with brake pads) actuated by spring-powered, pneumatic cylinders connected to these arms. Springs give specific spring-loading constant and exert predetermined load onto brake pads through lever arms. Pneumatic cylinders actuated positively to compress springs and disengage brake pads from disks. During power failure, brakes automatically lock onto disks, producing highly reliable, fail-safe stops. System doubles as stopping brake and "parking" brake.

  7. AUTOMOTIVE MAINTENANCE PLAN IMPROVEMENT BASED ON DISTRIBUTION OF FAILURE TIMES

    Directory of Open Access Journals (Sweden)

    Alexandru BOROIU

    2016-05-01

    Full Text Available In accordance with the concept of "RCM - Reliability Centered Maintenance", the paper presents a study on the possibility to improve maintenance plan for the most frequently replaced parts from a sample of cars, followed during the operation period: front/rear brake pads. After analyzing the reliability of these components, it is found that there is the possibility of introducing the obligatory replacement operation of brake pads who have reached the third technical inspection without being replaced, sacrificing resource exploitation of them, but improving the benefits for the client - the automotive availability.

  8. Techno-economic requirements for automotive composites

    Science.gov (United States)

    Arnold, Scot

    1993-01-01

    New technology generally serves two main goals of the automotive industry: one is to enable vehicles to comply with various governmental regulations and the other is to provide a competitive edge in the market. The latter goal can either be served through improved manufacturing and design capabilities, such as computer aided design and computer aided manufacturing, or through improved product performance, such as anti-lock braking (ABS). Although safety features are sometimes customer driven, such as the increasing use of airbags and ABS, most are determined by regulations as outlined by the Federal Motor Vehicle Safety Standards (FMVSS). Other standards, set by the Environmental Protection Agency, determine acceptable levels of emissions and fuel consumption. State governments, such as in California, are also setting precedent standards, such as requiring manufacturers to offer zero-emission vehicles as a certain fraction of their sales in the state. The drive to apply new materials in the automobile stems from the need to reduce weight and improve fuel efficiency. Topics discussed include: new lightweight materials; types of automotive materials; automotive composite applications; the role for composite materials in automotive applications; advantages and disadvantages of composite materials; material substitution economics; economic perspective; production economics; and composite materials production economics.

  9. Development of hydraulic brake actuator for active brake control; Active brake seigyoyo yuatsu booster no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, Y.; Hattori, M. Sugisawa, M.; Nishii, M. [Aisin Seiki Co. Ltd., Aichi (Japan)

    1997-10-01

    Recently, application of active brake control systems of the vehicle are increasing. (Vehicle stability control, Panic brake assist ) We have developed a new hydraulic brake actuator for active brake control systems. New hydraulic brake actuator is composed of the three parts. (Hydraulic booster unit, Power supply unit, Control valve unit) This report describes the construction of the new hydraulic booster unit. 2 refs., 10 figs.

  10. Automotive vehicle sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Raptis, A.C.; Moscynski, M.J.

    1995-09-01

    This report is an introduction to the field of automotive vehicle sensors. It contains a prototype data base for companies working in automotive vehicle sensors, as well as a prototype data base for automotive vehicle sensors. A market analysis is also included.

  11. Braking System Modeling and Brake Temperature Response to Repeated Cycle

    Directory of Open Access Journals (Sweden)

    Zaini Dalimus

    2014-12-01

    Full Text Available Braking safety is crucial while driving the passenger or commercial vehicles. Large amount of kinetic energy is absorbed by four brakes fitted in the vehicle. If the braking system fails to work, road accident could happen and may result in death. This research aims to model braking system together with vehicle in Matlab/Simulink software and measure actual brake temperature. First, brake characteristic and vehicle dynamic model were generated to estimate friction force and dissipated heat. Next, Arduino based prototype brake temperature monitoring was developed and tested on the road. From the experiment, it was found that brake temperature tends to increase steadily in long repeated deceleration and acceleration cycle.

  12. Chain of impact of the development of hot spots and hot rubbing in disk brakes of passenger cars; Wirkungskette der Entstehung von Hotspots und Heissrubbeln in Pkw-Scheibenbremsen

    Energy Technology Data Exchange (ETDEWEB)

    Sarda, Angelo

    2009-07-01

    Aspects coupled with brake comfort represent challenges with the development of brake systems. During the brake process, so-called hot spots on the surface of brake disks are developed under certain conditions. These hot spots result in an irregular thermal expansion and deformation of the brake disk. This results in vibrations impacting the comfort and being known as 'hot rubbing'. The author of the contribution under consideration describes the most important results from extensive benchmark tests and supplies experimentally secured realizations to the chain of impact of the development of hot spots and 'hot rubbing' in a disc brake.

  13. 49 CFR 393.52 - Brake performance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Brake performance. 393.52 Section 393.52... NECESSARY FOR SAFE OPERATION Brakes § 393.52 Brake performance. (a) Upon application of its service brakes... braking force is measured by a performance-based brake tester which meets the requirements of...

  14. Distribution and Dissipation of Braking Power of Wet Multidisc Brake%湿式多片制动器制动能的分配和耗散

    Institute of Scientific and Technical Information of China (English)

    阎清东; 宿新东

    2000-01-01

    研究湿式多片制动器制动过程制动能的分配和耗散,确定制动器的热负荷及摩擦偶件间热流分布的状况. 结合车辆的制动过程提出制动能四次分配的概念,利用有限元法计算制动能的三次、四次分配. 紧急制动中湿式多片制动器制动能的三次、四次分配主要与摩擦偶件的材料有关;持续制动中制动器吸收的能量主要由冷却润滑油带走. 为研究摩擦副的失效及摩擦材料的适用性提供了依据.%To study the distribution and dissipation of braking power of wet multidisc brake and determine thermal load and thermal flux distribution between mated discs, the concept of distributing brake power four times was put forward. The third and the fourth distribution of brake power were calculated by using finite element(FE) software ANSYS. The third and the fourth distribution of wet multidisc brake are mainly related to material characteristics of discs during emergency braking, while most of the braking power is carried off during continuous braking. Basis is provided for further analysis of disc failure and applicability of different friction materials.

  15. Engineering Design Handbook: Analysis and Design of Automotive Brake Systems.

    Science.gov (United States)

    1976-12-01

    node; i, OF eR = rotor surface emissivity, d’less T, - initial temperature, ýF 1 = mechanical efficiency, d’less Tj = temperature of nodej , OF O(z...temperature of node i, *F T/ = temperature of nodej , ’F For two-dimensional problems and a square grid 0.a ow,, u,,.ownI,, Nu with Ax = Ay, the basic

  16. A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

    Institute of Scientific and Technical Information of China (English)

    Credence Systems Corporation

    2004-01-01

    @@ Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.

  17. European Automotive Congress

    CERN Document Server

    Clenci, Adrian

    2016-01-01

    The volume includes selected and reviewed papers from the European Automotive Congress held in Bucharest, Romania, in November 2015. Authors are experts from research, industry and universities coming from 14 countries worldwide. The papers are covering the latest developments in fuel economy and environment, automotive safety and comfort, automotive reliability and maintenance, new materials and technologies, traffic and road transport systems, advanced engineering methods and tools, as well as advanced powertrains and hybrid and electric drives.

  18. Research of Motorcycle Braking Parameters

    Directory of Open Access Journals (Sweden)

    Loreta Levulytė

    2016-12-01

    Full Text Available From a technical point of view, in dangerous or emergency situation is very important motorcycle driver reaction and vehicle braking time. Motor-cycle deceleration parameters depend not only on the motorcycle brake system, but also on the driving experience. A significant influence on decel-eration the motorcycle has aerodynamic parameters, pavement type and condition, as well as the technical condition of the motocycle, shock absorb-ers, tire type and their technical condition. This article provides an analysis of the motorcycle longitudinal deceleration, braking modes of the mo-torcycle on a dry asphalt road surface. Motorcycle stopping – deceleration – acceleration efficiency issue, stopping in different modes. First ana-lyzed the dynamics of a motorcycle deceleration braking only the front wheel, then braked front and rear wheels and complex – then braked the front and rear wheels at the same time. The goal of experimental study is to determine the influence of braking modes intense fir motorcycle brak-ing deceleration when braking on dry road pavement, at three different braking modes, and set the braking path of change. Motorcycle decelera-tion in the longitudinal direction is an important parameter for analysis traffic accidents, for accident reconstruction process and the examination of motorcyclists technical possibility to avoid an accident.

  19. Morphology and properties of periwinkle shell asbestos-free brake pad

    Directory of Open Access Journals (Sweden)

    D.S. Yawas

    2016-01-01

    Full Text Available The development of asbestos-free automotive brake pad using periwinkle shell particles as frictional filler material is presented. This was with a view to exploiting the characteristics of the periwinkle shell, which is largely deposited as a waste, in replacing asbestos which has been found to be carcinogenic. Five sets of brake pads with different sieve size (710–125 μm of periwinkle shell particles with 35% resin were produced using compressive moulding. The physical, mechanical and tribological properties of the periwinkle shell particle-based brake pads were evaluated and compared with the values for the asbestos-based brake pads. The results obtained showed that compressive strength, hardness and density of the developed brake pad samples increased with decreasing the particle size of periwinkle shell from 710 to 125 μm, while the oil soak, water soak and wear rate decreased with decreasing the particle size of periwinkle shell. The results obtained at 125 μm of periwinkle shell particles compared favourably with that of commercial brake pad. The results of this research indicate that periwinkle shell particles can be effectively used as a replacement for asbestos in brake pad manufacture.

  20. Automotive electronics design fundamentals

    CERN Document Server

    Zaman, Najamuz

    2015-01-01

    This book explains the topology behind automotive electronics architectures and examines how they can be profoundly augmented with embedded controllers. These controllers serve as the core building blocks of today’s vehicle electronics. Rather than simply teaching electrical basics, this unique resource focuses on the fundamental concepts of vehicle electronics architecture, and details the wide variety of Electronic Control Modules (ECMs) that enable the increasingly sophisticated "bells & whistles" of modern designs.  A must-have for automotive design engineers, technicians working in automotive electronics repair centers and students taking automotive electronics courses, this guide bridges the gap between academic instruction and industry practice with clear, concise advice on how to design and optimize automotive electronics with embedded controllers.

  1. Durability investigation on torque control of a magneto-rheological brake: experimental work

    Science.gov (United States)

    Kim, Wan Ho; Park, Jhin Ha; Kim, Gi-Woo; Shin, Cheol Soo; Choi, Seung-Bok

    2017-03-01

    This study experimentally investigates the torque control durability of a disc brake featuring a magneto-rheological (MR) fluid. An appropriate size of MR disc brake is designed based on a mathematical model, and a prototype is manufactured. A small-scale laboratory-scale test bed is then developed using a DC motor, in-line torque sensor, and the MR brake. S45C and S20C steels are inserted into a tapered hole on the surface of the brake disc. After 105 cycles of operation in shear mode, the wear properties of the MR brake are characterized by average surface roughness measurements, scanning electron microscope images, and energy dispersive x-ray spectra. The torque control performances before and after the operation cycles are examined using open-loop control and closed-loop proportional-integral-derivative control. As expected, the control performance degraded after 105 cycles of operation in the open-loop case, but not in the closed-loop case. This aspect is demonstrated by the sinusoidal torque-tacking control performance before and after the operation cycles.

  2. Clutches and brakes design and selection

    CERN Document Server

    Orthwein, William C

    2004-01-01

    FRICTION MATERIALSFriction CodeWearBrake FadeFriction MaterialsNotationReferencesBAND BRAKESDerivation of EquationsApplicationLever-Actuated Band Brake: Backstop DesignExample: Design of a BackstopNotationFormula CollectionReferencesEXTERNALLY AND INTERNALLY PIVOTED SHOE BRAKESPivoted External Drum BrakesPivoted Internal Drum BrakesDesign of Dual-Anchor Twin-Shoe Drum BrakesDual-Anchor Twin-Shoe Drum Brake Design ExamplesDesign of Single-Anchor Twin-Shoe Drum BrakesSingle-Anchor Twin-Shoe Drum Brake Design Exam

  3. National Automotive Center - NAC

    Data.gov (United States)

    Federal Laboratory Consortium — Encouraged by the advantages of collaboration, the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) worked with the Secretary of the...

  4. FSC赛车制动系统设计%FSC racing brake system design

    Institute of Scientific and Technical Information of China (English)

    吴祥超; 赵运德; 鲁雄文

    2014-01-01

    A design method of brake system that is applicable to theFormula Student China racing car is proposed in this paper. A simple hydraulic disc brake system is chosen, and adding balance bar is to regulate the distribution coefficient of braking force. Calculation and analysis show that the braking system can meet the requirements of dynamic testing during the game.%本文提出了一套适用于FSC赛车制动系统的设计方法。选用简单液压盘式制动系统,并且加装平衡杆以调节制动器制动力分配系数。计算和分析表明,该制动系统能够满足比赛时动态测试的要求。

  5. An analysis of braking measures

    NARCIS (Netherlands)

    De Groot, S.; De Winter, J.C.F.; Wieringa, P.A.; Mulder, M.

    2010-01-01

    Braking to a full stop at a prescribed target position is a driving manoeuvre regularly used in experiments to investigate driving behaviour or to test vehicle acceleration feedback systems in simulators. Many different performance measures have been reported in the literature for analysing braking.

  6. Thermal Characterisation of Brake Pads

    DEFF Research Database (Denmark)

    Ramousse, Séverine; Høj, Jakob Weiland; Sørensen, O. T.

    2001-01-01

    The chemical-physical decomposition processes that occur in a brake pad heated to 1000degreesC have been studied. This temperature can be reached when a brake pad is applied. Thermogravimetry and differential thermal analysis were used in combination with evolved gas analysis, and image analysis...

  7. Fireproof Brake Hydraulic System.

    Science.gov (United States)

    1981-09-01

    bulk modulus and density are the same (see Table 2). AO-2 is the base stock fluid for AO-8 which is a blend of AO-2 and a viscosity index (VI) improver...RADIANS LI+ BRAK .. .... " 17 . 3000 4 BRAKE .~1~~ 4~~I 4 4 4- 4 .! L 3 00 00i- FTLB 0 ’ 25 00 +--- + + i DISPCE EN FiueE4 raeSse taiiy tndr ytm...VA LVE ... it .. . . .. . F... .. igur E. 8 Brak Syste Stability...... .. .. .. .. Tw-FuRRSstNTer Daming Amit 327. .. .. .. .... APPENDIX F

  8. The Tribological Efficiency and the Mechanism of Action of Nano-Porous Composition Base Brake Lining Materials

    Science.gov (United States)

    Kutelia, E. R.; Gventsadze, D. I.; Eristavil, B. G.; Maisuradze, N. I.; Tsurtsumia, O. O.; Gventsadze, L. D.; Olofsson, U.; Wahlström, J.; Olander, L.

    2011-12-01

    Based on the comparative analysis of the experimental values determined for the tribological parameters for the three novel nano-porous composition base and two conventional brake lining materials while friction with the grey cast iron disc, it was shown the considerable high tribological efficiency of the novel nano-porous composition base lining materials in comparison with the conventional (from EU and USA market) brake lining materials. The explanation is given to the action mechanism of nano-porous composition base brake lining material and its tribological efficiency basing on the "triple phase" tribo-pair model.

  9. 49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic brake subsystem. The following requirements apply to vehicles with air brake and...

  10. Turbulent drag reduction through oscillating discs

    CERN Document Server

    Wise, Daniel J

    2014-01-01

    The changes of a turbulent channel flow subjected to oscillations of wall flush-mounted rigid discs are studied by means of direct numerical simulations. The Reynolds number is $R_\\tau$=$180$, based on the friction velocity of the stationary-wall case and the half channel height. The primary effect of the wall forcing is the sustained reduction of wall-shear stress, which reaches a maximum of 20%. A parametric study on the disc diameter, maximum tip velocity, and oscillation period is presented, with the aim to identify the optimal parameters which guarantee maximum drag reduction and maximum net energy saving, computed by taking into account the power spent to actuate the discs. This may be positive and reaches 6%. The Rosenblat viscous pump flow is used to predict the power spent for disc motion in the turbulent channel flow and to estimate localized and transient regions over the disc surface subjected to the turbulent regenerative braking effect, for which the wall turbulence exerts work on the discs. The...

  11. 49 CFR 238.231 - Brake system.

    Science.gov (United States)

    2010-10-01

    ... by testing or previous service. (h) Hand brakes and parking brakes. (1) Except for a locomotive that..., and except for MU locomotives, all locomotives shall be equipped with a hand or parking brake that can... locomotives, on locomotives so equipped, the hand or parking brake as well as its parts and connections...

  12. The Role of Solid Lubricants for Brake Friction Materials

    Directory of Open Access Journals (Sweden)

    Werner Österle

    2016-02-01

    Full Text Available This review article comprises of three parts. Firstly, reports of brake manufacturers on the beneficial impact of solid lubricants for pad formulations are surveyed. Secondly, since tribofilms were identified to play a crucial role in friction stabilization and wear reduction, the knowledge about tribofilm structures formed during automotive braking was reviewed comprehensively. Finally, a model for simulating the sliding behavior of tribofilms is suggested and a review on modelling efforts with different model structures related to real tribofilms will be presented. Although the variety of friction composites involved in commercial brake systems is very broad, striking similarities were observed in respect to tribofilm nanostructures. Thus, a generalization of the tribofilm nanostructure is suggested and prerequisites for smooth sliding performance and minimal wear rates have been identified. A minimum of 13 vol % of soft inclusions embedded in an iron oxide based tribofilm is crucial for obtaining the desired properties. As long as the solid lubricants or their reaction products are softer than magnetite, the main constituent of the tribofilm, the model predicts smooth sliding and minimum wear.

  13. Making aerospace technology work for the automotive industry, introduction

    Science.gov (United States)

    Olson, W. T.

    1978-01-01

    NASA derived technology already in use in the automotive industry include: (1) developments in electronics design, computer systems, and quality control methods for line testing of cars and trucks; (2) a combustion analysis computer program for automotive engine research and development; (3) an infrared scanner and television display for analyzing tire design and performance, and for studying the effects of heat on the service life of V-belts, shock mounts, brakes, and rubber bearings; (4) exhaust gas analyzers for trouble shooting and emissions certification; (5) a device for reducing noise from trucks; and (6) a low cost test vehicle for measuring highway skid resistance. Services offered by NASA to facilitate access to its technology are described.

  14. Transient switching control strategy from regenerative braking to anti-lock braking with a semi-brake-by-wire system

    Science.gov (United States)

    Li, Liang; Li, Xujian; Wang, Xiangyu; Liu, Yahui; Song, Jian; Ran, Xu

    2016-02-01

    Regenerative braking is an important technology in improving fuel economy of an electric vehicle (EV). However, additional motor braking will change the dynamic characteristics of the vehicle, leading to braking instability, especially when the anti-lock braking system (ABS) is triggered. In this paper, a novel semi-brake-by-wire system, without the use of a pedal simulator and fail-safe device, is proposed. In order to compensate for the hysteretic characteristics of the designed brake system while ensure braking reliability and fuel economy when the ABS is triggered, a novel switching compensation control strategy using sliding mode control is brought forward. The proposed strategy converts the complex coupling braking process into independent control of hydraulic braking and regenerative braking, through which a balance between braking performance, braking reliability, braking safety and fuel economy is achieved. Simulation results show that the proposed strategy is effective and adaptable in different road conditions while the large wheel slip rate is triggered during a regenerative braking course. The research provides a new possibility of low-cost equipment and better control performance for the regenerative braking in the EV and the hybrid EV.

  15. Numerical investigation of a three-dimensional disc-pad model with and without thermal effects

    Directory of Open Access Journals (Sweden)

    Belhocine Ali

    2015-01-01

    Full Text Available This study aims to identify thermal effects in the structure and the contact behavior of a disc-pad assembly using a finite element approach. The first analysis is performed on the disc-pad model in the absence of thermal effects. The structural performance of the disc-pad model is predicted in terms of factors such as the deformation and Von Mises stress. Next, thermomechanical analysis is performed on the same disc-pad model with the inclusion of convection, adiabatic, and heat flux elements. The predicted temperature distribution, deformation, stress, and contact pressure are presented. The structural performance between the two analyses (mechanical and thermomechanical is compared. This study can assist brake engineers in choosing a suitable analysis method to critically evaluate the structural and contact behavior of the disc brake assembly.

  16. Brake Stops Both Rotation And Translation

    Science.gov (United States)

    Allred, Johnny W.; Fleck, Vincent J., Jr.

    1995-01-01

    Combination of braking and positioning mechanisms allows both rotation and translation before brake engaged. Designed for use in positioning model airplane in wind tunnel. Modified version used to position camera on tripod. Brake fast and convenient to use; contains single actuator energizing braking actions against both rotation and translation. Braking actuator electric, but pneumatic actuator could be used instead. Compact and lightweight, applies locking forces close to load, and presents minimal cross section to airflow.

  17. High integrity automotive castings

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D. [Eck Industries Inc., St. Manitowoc, WI (United States)

    2007-07-01

    This paper described the High Integrity Magnesium Automotive Casting (HI-MAC) program, which was developed to ensure the widespread adoption of magnesium in structural castings. The program will encourage the use of low pressure permanent molds, squeeze casting, and electromagnetic pumping of magnesium into dies. The HI-MAC program is currently investigating new heat treatment methods, and is in the process of creating improved fluid flow and solidification modelling to produce high volume automotive components. In order to address key technology barriers, the program has been divided into 8 tasks: (1) squeeze casting process development; (2) low pressure casting technology; (3) thermal treatment; (4) microstructure control; (5) computer modelling and properties; (6) controlled molten metal transfer and filling; (7) emerging casting technologies; and (8) technology transfer throughout the automotive value chain. Technical challenges were outlined for each of the tasks. 1 ref., 3 tabs., 5 figs.

  18. Identification for automotive systems

    CERN Document Server

    Hjalmarsson, Håkan; Re, Luigi

    2012-01-01

    Increasing complexity and performance and reliability expectations make modeling of automotive system both more difficult and more urgent. Automotive control has slowly evolved from an add-on to classical engine and vehicle design to a key technology to enforce consumption, pollution and safety limits. Modeling, however, is still mainly based on classical methods, even though much progress has been done in the identification community to speed it up and improve it. This book, the product of a workshop of representatives of different communities, offers an insight on how to close the gap and exploit this progress for the next generations of vehicles.

  19. Automotive NVH technology

    CERN Document Server

    Nijman, Eugenius; Priebsch, Hans-Herwig

    2016-01-01

    This book presents seven chapters examining selected noise, vibration and harshness (NVH) topics that are highly relevant for automotive vehicle development. These include applications following the major trends toward increased passenger comfort, vehicle electrification and lightweight design. The authors of the seven chapters, all of which are experts from the automotive industry and academia, present the foremost challenges and potential solutions in this demanding field. Among others, applications for sound optimization in downsized engines, noise optimization in electric powertrains, weight reduction options for exhaust systems, porous materials description, and the vibro-acoustic analysis of geared systems are discussed.

  20. Magnetic fields in giant planet formation and protoplanetary discs

    Science.gov (United States)

    Keith, Sarah Louise

    2015-12-01

    Protoplanetary discs channel accretion onto their host star. How this is achieved is critical to the growth of giant planets which capture their massive gaseous atmosphere from the surrounding flow. Theoretical studies find that an embedded magnetic field could power accretion by hydromagnetic turbulence or torques from a large-scale field. This thesis presents a study of the inuence of magnetic fields in three key aspects of this process: circumplanetary disc accretion, gas flow across gaps in protoplanetary discs, and magnetic-braking in accretion discs. The first study examines the conditions needed for self-consistent accretion driven by magnetic fields or gravitational instability. Models of these discs typically rely on hydromagnetic turbulence as the source of effective viscosity. However, magnetically coupled,accreting regions may be so limited that the disc may not support sufficient inflow. An improved Shakura-Sunyaev ? disc is used to calculate the ionisation fraction and strength of non-ideal effects. Steady magnetically-driven accretion is limited to the thermally ionised, inner disc so that accretion in the remainder of the disc is time-dependent. The second study addresses magnetic flux transport in an accretion gap evacuated by a giant planet. Assuming the field is passively drawn along with the gas, the hydrodynamical simulation of Tanigawa, Ohtsuki & Machida (2012) is used for an a posteriori analysis of the gap field structure. This is used to post-calculate magnetohydrodynamical quantities. This assumption is self-consistent as magnetic forces are found to be weak, and good magnetic coupling ensures the field is frozen into the gas. Hall drift dominates across much of the gap, with the potential to facilitate turbulence and modify the toroidal field according to the global field orientation. The third study considers the structure and stability of magnetically-braked accretion discs. Strong evidence for MRI dead-zones has renewed interest in

  1. Bringing Excellence to Automotive

    Science.gov (United States)

    Večeřa, Pavel; Paulová, Iveta

    2012-12-01

    Market situation and development in recent years shows, that organization's ability to meet customer requirements is not enough. Successful organizations are able to exceed the expectations of all stakeholders. They are building their excellence systematically. Our contribution basically how the excellence in automotive is created using EFQM Excellence Model in Total Quality Management.

  2. Brake Performance Analysis of ABS for Eddy Current and Electrohydraulic Hybrid Brake System

    Directory of Open Access Journals (Sweden)

    Ren He

    2013-01-01

    Full Text Available This paper introduces an eddy current and electro-hydraulic hybrid brake system to solve problems such as wear, thermal failure, and slow response of traditional vehicle brake system. Mathematical model was built to calculate the torque of the eddy current brake system and hydraulic brake system and analyze the braking force distribution between two types of brake systems. A fuzzy controller on personal computer based on LabVIEW and Matlab was designed and a set of hardware in the loop system was constructed to validate and analyze the performance of the hybrid brake system. Through lots of experiments on dry and wet asphalt roads, the hybrid brake system achieves perfect performance on the experimental bench, the hybrid system reduces abrasion and temperature of the brake disk, response speed is enhanced obviously, fuzzy controller keeps high utilization coefficient due to the optimal slip ratio regulation, and the total brake time has a smaller decrease than traditional hydraulic brake system.

  3. Accretion and magnetic field morphology around Class 0 stage protostellar discs

    CERN Document Server

    Seifried, D; Pudritz, R E; Klessen, R S

    2014-01-01

    We analyse the results of existing and newly performed and simulations of turbulent, collapsing molecular cloud cores focussing on the formation of Class 0 stage protostellar discs and the physical conditions in their surroundings. We show that for a wide range of initial conditions rotationally supported discs are formed in the Class 0 stage already. In particular, we show that even mild, i.e. subsonic turbulent motions, reduce the magnetic braking efficiency sufficiently in order to allow Keplerian discs to form. Based on this result we suggest that already during the Class 0 stage the fraction of Keplerian discs is significantly higher than 50%. This is consistent with recent observational trends but significantly higher than predictions based on simulations with misaligned magnetic fields and disc angular momentum vectors, demonstrating the importance of turbulent motions for the formation of Keplerian discs. We show that the accretion of mass and angular momentum in the surroundings of protostellar discs...

  4. A global strategy based on experiments and simulations for squeal prediction on industrial railway brakes

    Science.gov (United States)

    Sinou, J.-J.; Loyer, A.; Chiello, O.; Mogenier, G.; Lorang, X.; Cocheteux, F.; Bellaj, S.

    2013-09-01

    This paper presents an overview of recent experimental and numerical investigations on industrial railway brakes. The goal of the present study is to discuss the relevance of the mechanical modeling strategy for squeal prediction. Specific experimental set-ups based on transient and controlled braking tests are designed for this purpose. Measurements are performed on it to investigate the dynamic behavior of TGV squeal noise and its squeal characterization through experiments. It will be demonstrated that it is possible to build consistent and efficient finite element models to simulate squeal events in TGV brake systems. The numerical strategy will be presented, including not only the modeling of the TGV brake system and the stability analysis, but also the transient nonlinear dynamic and computational process based on efficient reduced basis. This complete numerical strategy allows us to perform relevance squeal prediction on industrial railway brakes. This study comes within the scope of a research program AcouFren that is supported by ADEME (Agence De l'Environnement et de la Maîtrise de l'Energie) concerning the reduction of the squeal noise generated by high power railway disc brakes. experiments with an evolution of the rotational speed of the disc: these tests are called "transient braking tests" and correspond to real braking tests, experiments with a controlled steady rotational speed (i.e. dynamic fluctuations in rotational speed are not significant): these tests are called "controlled braking tests". In the present study, the Continuous Wavelet Transform (CWT) [20] is used to study the time-history responses of the TGV brake system. So, a brief basic theory of the wavelet analysis that transforms a signal into wavelets that are well localized both in frequency and time is presented in this part of the paper. Considering a function f(t), the associated Continuous Wavelet Transform (CWT) corresponds to a wavelet transform given by W(a,b

  5. Magnetic Braking Revisited

    CERN Document Server

    Taam, R E

    2003-01-01

    We present a description for the angular momentum loss rate due to magnetic braking for late type stars taking into account recent observational data on the relationship between stellar activity and rotation. The analysis is based on an idealized two component coronal model subject to constraints imposed on the variation of the coronal gas density with rotation period inferred from the observed variation of X-ray luminosity, L_x, with rotation rate, Omega, (L_x \\propto Omega^2) for single rotating dwarfs. An application of the model to high rotation rates leads to a gradual turnover of the X-ray luminosity which is similar to the saturation recently observed in rapidly rotating dwarfs. The resulting angular momentum loss rate, \\dot J, depends on Omega in the form \\dot J \\propto Omega^beta where beta ~ 3 for slow rotators and ~ 1.3 for fast rotators. The relation at high rotation rates significantly differs from the power law exponent for slowly rotating stars, depressing the angular momentum loss rate without...

  6. Broken discs: warp propagation in accretion discs

    OpenAIRE

    Nixon, Chris; King, Andrew

    2012-01-01

    We simulate the viscous evolution of an accretion disc around a spinning black hole. In general any such disc is misaligned, and warped by the Lense-Thirring effect. Unlike previous studies we use effective viscosities constrained to be consistent with the internal fluid dynamics of the disc. We find that nonlinear fluid effects, which reduce the effective viscosities in warped regions, can promote the breaking of the disc into two distinct planes. This occurs when the Shakura & Sunyaev dimen...

  7. On the potential of uncertainty analysis for prediction of brake squeal propensity

    Science.gov (United States)

    Zhang, Zhi; Oberst, Sebastian; Lai, Joseph C. S.

    2016-09-01

    Brake squeal is a source of significant warranty-related claims for automotive manufacturers because it is annoying and is often perceived by customers as a safety concern. A brake squeal analysis is complex due to changing environmental and operating conditions, high sensitivity to manufacturing and assembly tolerances as well as the not so well understood role of nonlinearities. Although brake squeal is essentially a nonlinear problem, the standard analysis tool in industry is the linear complex eigenvalue analysis (CEA) which may under-predict or over-predict the number of unstable vibration modes. A nonlinear instability analysis is more predictive than CEA but is still computationally too expensive to be used routinely in industry for a full brake finite element model. Also, although the net work analysis of a linearised brake system has shown potential in predicting the origin of brake squeal, it has not been extensively used. In this study, the net work of an analytical viscously damped self-excited 4-dof friction oscillator with cubic contact force nonlinearity is compared with the instability prediction using the CEA and a nonlinear instability analysis. Results show that both the net work analysis and CEA under-predict the instability because of their inability to detect the sub-critical Hopf bifurcation. Then, the uncertainty analysis is applied to examine if it can improve instability prediction of a nonlinear system using linear methods and its limitations. By applying a variance-based global sensitivity analysis to parameters of the oscillator, suitable candidates for an uncertainty analysis are identified. Results of uncertainty analyses by applying polynomial chaos expansions to net work and CEA correlate well with those of the nonlinear analysis, hence demonstrating the potential of an uncertainty analysis in improving the prediction of brake squeal propensity using a linear method.

  8. Conditions for circumstellar disc formation - II. Effects of initial cloud stability and mass accretion rate

    Science.gov (United States)

    Machida, Masahiro N.; Matsumoto, Tomoaki; Inutsuka, Shu-ichiro

    2016-12-01

    Disc formation in strongly magnetized cloud cores is investigated using a three-dimensional magnetohydrodynamic simulation with a focus on the effects of the initial cloud stability and the mass accretion rate. The initial cloud stability greatly alters the disc formation process even for prestellar clouds with the same mass-to-flux ratio. A high mass accretion rate on to the disc-forming region is realized in initially unstable clouds, and a large angular momentum is introduced into the circumstellar region in a short time. The region around the protostar has both a thin infalling envelope and a weak magnetic field, which both weaken the effect of magnetic braking. The growth of the rotation-supported disc is promoted in such unstable clouds. Conversely, clouds in an initially near-equilibrium state show lower accretion rates of mass and angular momentum. The angular momentum is transported to the outer envelope before protostar formation. After protostar formation, the circumstellar region has a thick infalling envelope and a strong magnetic field that effectively brakes the disc. As a result, disc formation is suppressed when the initial cloud is in a nearly stable state. The density distribution of the initial cloud also affects the disc formation process. Disc growth strongly depends on the initial conditions when the prestellar cloud has a uniform density, whereas there is no significant difference in the disc formation process in prestellar clouds with non-uniform densities.

  9. The design of brake fatigue testing system

    Directory of Open Access Journals (Sweden)

    Huang, Xiaoya

    2015-01-01

    Full Text Available Brake is used to reduce the operating speed of the machinery equipment or to make it stop. It is essential for vehicles, climbing machines and many fixed equipment in their safety work. Brake tester is an experimental apparatus to measure and analyse the braking performance. Based on the PLC technology and for the purpose of testing brake shoe friction material’s life, this paper designed a virtual brake test platform. In it, inverter were used to control the motor, so that it can load automatically and ensure brake drum constant speed output; what is more, closed loop control system were used to control the brake shoe, so that the cylinder pressure keeps stable in the process of dynamic braking.

  10. Rotordynamics of automotive turbochargers

    CERN Document Server

    Nguyen-Schäfer, Hung

    2015-01-01

    Rotordynamics of automotive turbochargers is dealt with in this book encompassing the widely working field of small turbomachines under real operating conditions at the very high rotor speeds up to 300000 rpm. The broadly interdisciplinary field of turbocharger rotordynamics involves 1) Thermodynamics and Turbo-Matching of Turbochargers 2) Dynamics of Turbomachinery 3) Stability Analysis of Linear Rotordynamics with the Eigenvalue Theory 4) Stability Analysis of Nonlinear Rotordynamics with the Bifurcation Theory 5) Bearing Dynamics of the Oil Film using the Two-Phase Reynolds Equation 6) Computation of Nonlinear Responses of a Turbocharger Rotor 7) Aero and Vibroacoustics of Turbochargers 8) Shop and Trim Balancing at Two Planes of the Rotor 9) Tribology of the Bearing Surface Roughness 10) Design of Turbocharger Platforms using the Similarity Laws The rotor response of an automotive turbocharger at high rotor speeds is studied analytically, computationally, and experimentally. Due to the nonlinear character...

  11. Automotive Industry in Malaysia

    DEFF Research Database (Denmark)

    Wad, Peter; Govindaraju, V.G.R. Chandran

    2011-01-01

    expanded in terms of sales, production, employment and local content, but failed in industrial upgrading and international competitiveness. The failures can be attributed to (a) lack of political promotion for high challenge-high support environment, (b) low technological and marketing capabilities and (c......This paper explains the evolution and assesses the development of the Malaysian automotive industry within the premise of infant industry and trade protection framework as well as extended arguments of infant industry using a global value chain perspective. The Malaysian automotive industry......) limited participation in the global value chain. Although the Malaysian infant industry protection policy comprised many promising initiatives, the national and the overall domestic automobile industry ended up as a captive of the regionalised Japanese keiretsu system in automobile manufacturing. A new...

  12. Current Automotive Holometry Studies

    Science.gov (United States)

    Marchi, Mitchell M.; Snyder, D. S.

    1990-04-01

    Holometry studies of automotive body and powertrain components have become a very useful high resolution test methodology to knowledgeable Ford engineering personnel. Current examples of studies that represent the static or dynamic operational conditions of the automotive test component are presented. Continuous wave laser holometry, computer aided holometry (CAH) and pulsed laser holometry were the holometric techniques used to study the following subjects: (1) body in prime (BIP) vibration modes, (2) transmission flexplate stud-torque converter deformation due to engine torque pulses, (3) engine cylinder head and camshaft support structure deformation due to cylinder pressure and (4) engine connecting rod/cap lift-off. Static and dynamic component loading and laboratory techniques required to produce usable and valid test results are discussed along with possible conclusions for the engineering concerns.

  13. A Secure Mechanism to Supervise Automotive Sensor Network by Client on Smart Phone

    Directory of Open Access Journals (Sweden)

    T R Yashavanth

    2013-03-01

    Full Text Available This paper presents a proposal on design of a secure client on smart phone to monitor automotive sensor network. Recently, more and more vehicles, such as BMW X5, are connected from outside via smart phone [3]. From smart phone, users can use the internet resources in automotive. Users can monitor the automotives by using their smart phones. When the automotive is moving or stolen by robber, alert information will be reported to users and users can even brake their automotive via smart phone in emergency status by sending control command to the vehicle information gateway. So client software in smart phone is required to monitor the sensor network in automotives. In order to prevent malicious attack on the client software by malicious attackers which are usually the robbers, there should be a mechanism provided to the clients which offers security by considering few criteria’s like power of computation, level of security and consumption of power. This proposed method uses IDEA for the encryption of all the messages since IDEA has high level of security and suitable to implement in software and also demands on computational power is less. Record management set is being suggested for the storage of critical data which is a Java MIDlet based mechanism. Between client software and its gateway a communication management on transaction is also proposed. The verification of the key updating process is verified with model checking in UPPAAL [7].

  14. FISITA 2012 World Automotive Congress

    CERN Document Server

    2013-01-01

    Proceedings of the FISITA 2012 World Automotive Congress are selected from nearly 2,000 papers submitted to the 34th FISITA World Automotive Congress, which is held by Society of Automotive Engineers of China (SAE-China ) and the International Federation of Automotive Engineering Societies (FISITA). This proceedings focus on solutions for sustainable mobility in all areas of passenger car, truck and bus transportation. Volume 8: Vehicle Design and Testing (II) focuses on: •Automotive Reliability Technology •Lightweight Design Technology •Design for Recycling •Dynamic Modeling •Simulation and Experimental Validation •Virtual Design, Testing and Validation •Testing of Components, Systems and Full Vehicle Above all researchers, professional engineers and graduates in fields of automotive engineering, mechanical engineering and electronic engineering will benefit from this book.   SAE-China is a national academic organization composed of enterprises and professionals who focus on research, design a...

  15. Brakes, brake control and driver assistance systems function, regulation and components

    CERN Document Server

    2014-01-01

    Braking systems have been continuously developed and improved throughout the last years. Major milestones were the introduction of antilock braking system (ABS) and electronic stability program. This reference book provides a detailed description of braking components and how they interact in electronic braking systems. Contents Motor vehicle safety.- Basic principles of vehicle dynamics.- Car braking systems.- Car braking-system components.- Wheel brakes.- Antilock breaking systems.- Traction control system.- Electronic stability program.- Automatic brake functions.- Hydraulic modulator.- Sensors for brake control.- Sensotronic brake control.- Active steering.- Occupant protection systems.- Driver assistance systems.- Adaptive cruise control.- Parking systems.- Instrumentation.- Orientation methods.- Navigation systems.- Workshop technology. The target groups Motor-vehicle technicians in education and vocational training Master-mechanics and technicians in garage-workshops Teachers and lecturers in vocation...

  16. Magnetic braking in ultracompact binaries

    CERN Document Server

    Farmer, Alison

    2010-01-01

    Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether magnetically coupled winds could in fact lead to substantial additional angular momentum losses. We remark that the scaling relations often invoked for the relative importance of gravitational and magnetic braking do not apply, and instead use simple non-empirical expressions for the braking rates. In order to remove significant angular momentum, the wind must be tied to field lines anchored in one of the binary's component stars; uncertainties remain as to the driving mechanism for such a wind. In the case of white dwarf accretors, we find that magnetic braking can potentially remove angular momentum on comparable or even shorter timescales than gravitational waves over a large range in orbital period. We present such a solution for the 17-minute binary AM CVn itself which a...

  17. 30 CFR 56.14101 - Brakes.

    Science.gov (United States)

    2010-07-01

    ... equipped on self-propelled mobile equipment, parking brakes shall be capable of holding the equipment with... stop under normal operating conditions. Parking or emergency (secondary) brakes are not to be actuated... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Brakes. 56.14101 Section 56.14101...

  18. 49 CFR 236.712 - Brake pipe.

    Science.gov (United States)

    2010-10-01

    ...-pneumatic brake equipment on each vehicle of the train. ... 49 Transportation 4 2010-10-01 2010-10-01 false Brake pipe. 236.712 Section 236.712 Transportation... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A...

  19. Mountain Braking Test Venue Study

    Science.gov (United States)

    2013-12-12

    resistance, and engine braking. The following equation shows this relationship: PB = W ∙ V ∙ ϴ - PA – PRR – PE. (1) The engine braking power...vehicle rolling resistance is due to tires and can be characterized as: PRR = CRR ∙ W ∙ V ∙ CT / 375 (HP), (3) where CRR is the tire-road interface...resistance is proportional to tire load results in the following equation: PRR = (0.0002455 ∙ V2 + 1.784 ∙ V) ∙ W/80,000 (HP). (4) The power absorbed

  20. Braking performance of aircraft tires

    Science.gov (United States)

    Agrawal, Satish K.

    This paper brings under one cover the subject of aircraft braking performance and a variety of related phenomena that lead to aircraft hydroplaning, overruns, and loss of directional control. Complex processes involving tire deformation, tire slipping, and fluid pressures in the tire-runway contact area develop the friction forces for retarding the aircraft; this paper describes the physics of these processes. The paper reviews the past and present research efforts and concludes that the most effective way to combat the hazards associated with aircraft landings and takeoffs on contaminated runways is by measuring and displaying in realtime the braking performance parameters in the aircraft cockpit.

  1. Angular momentum transport in the magnetospheres of cataclysmic variable accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Koen, C.

    1986-12-01

    The theory of stellar magnetic braking is applied to circumstellar discs. The focus is concentrated on cataclysmic variable stars but results apply to any disc in which the rotational velocity is Keplerian. Calculations are done for two magnetic field configurations and numerical results given for a range of physical parameter values. It is found that magnetic processes could be efficient in the removal of angular momentum from such systems.

  2. Structural and Contact Analysis of a 3-Dimensional Disc-Pad Model with and without Thermal Effects

    Directory of Open Access Journals (Sweden)

    A. Belhocine

    2014-12-01

    Full Text Available The motivation of this work is to identify thermal effects on the structural and contact behaviour of a disc-pad assembly using a finite element approach. The first analysis is performed on the disc-pad model without the presence of thermal properties. Structural performance of the disc-pad model such as deformation and Von Mises stress is predicted. Next, thermomechanical analysis is performed on the same disc-pad model with the inclusion of convection, adiabatic and heat flux elements. The prediction results of temperature distribution, deformation, stress and contact pressure are presented. Comparison of the structural performance between the two analyses (mechanical and thermomechanical is also made. From this study, it can assist brake engineers to choose a suitable analysis in order to critically evaluate structural and contact behaviour of the disc brake assembly.

  3. The design of brake fatigue testing system

    OpenAIRE

    2015-01-01

    Brake is used to reduce the operating speed of the machinery equipment or to make it stop. It is essential for vehicles, climbing machines and many fixed equipment in their safety work. Brake tester is an experimental apparatus to measure and analyse the braking performance. Based on the PLC technology and for the purpose of testing brake shoe friction material’s life, this paper designed a virtual brake test platform. In it, inverter were used to control the motor, so that it can load automa...

  4. Product Quality Improvement Using FMEA for Electric Parking Brake (EPB)

    Science.gov (United States)

    Dumitrescu, C. D.; Gruber, G. C.; Tişcă, I. A.

    2016-08-01

    One of the most frequently used methods to improve product quality is complex FMEA. (Failure Modes and Effects Analyses). In the literature various FMEA is known, depending on the mode and depending on the targets; we mention here some of these names: Failure Modes and Effects Analysis Process, or analysis Failure Mode and Effects Reported (FMECA). Whatever option is supported by the work team, the goal of the method is the same: optimize product design activities in research, design processes, implementation of manufacturing processes, optimization of mining product to beneficiaries. According to a market survey conducted on parts suppliers to vehicle manufacturers FMEA method is used in 75%. One purpose of the application is that after the research and product development is considered resolved, any errors which may be detected; another purpose of applying the method is initiating appropriate measures to avoid mistakes. Achieving these two goals leads to a high level distribution in applying, to avoid errors already in the design phase of the product, thereby avoiding the emergence and development of additional costs in later stages of product manufacturing. During application of FMEA method using standardized forms; with their help will establish the initial assemblies of product structure, in which all components will be viewed without error. The work is an application of the method FMEA quality components to optimize the structure of the electrical parking brake (Electric Parching Brake - E.P.B). This is a component attached to the roller system which ensures automotive replacement of conventional mechanical parking brake while ensuring its comfort, functionality, durability and saves space in the passenger compartment. The paper describes the levels at which they appealed in applying FMEA, working arrangements in the 4 distinct levels of analysis, and how to determine the number of risk (Risk Priority Number); the analysis of risk factors and established

  5. Selection of magnetorheological brake types via optimal design considering maximum torque and constrained volume

    Science.gov (United States)

    Nguyen, Q. H.; Choi, S. B.

    2012-01-01

    This research focuses on optimal design of different types of magnetorheological brakes (MRBs), from which an optimal selection of MRB types is identified. In the optimization, common types of MRB such as disc-type, drum-type, hybrid-types, and T-shaped type are considered. The optimization problem is to find the optimal value of significant geometric dimensions of the MRB that can produce a maximum braking torque. The MRB is constrained in a cylindrical volume of a specific radius and length. After a brief description of the configuration of MRB types, the braking torques of the MRBs are derived based on the Herschel-Bulkley model of the MR fluid. The optimal design of MRBs constrained in a specific cylindrical volume is then analysed. The objective of the optimization is to maximize the braking torque while the torque ratio (the ratio of maximum braking torque and the zero-field friction torque) is constrained to be greater than a certain value. A finite element analysis integrated with an optimization tool is employed to obtain optimal solutions of the MRBs. Optimal solutions of MRBs constrained in different volumes are obtained based on the proposed optimization procedure. From the results, discussions on the optimal selection of MRB types depending on constrained volumes are given.

  6. Braking Distance Prediction by Hydroplaning Analysis of 3-D Patterned Tire Model

    Science.gov (United States)

    Cho, Jin-Rae; Choi, Joo-Hyoung; Lee, Hong-Woo; Woo, Jong-Shik; Yoo, Wan-Suk

    In this paper, we present a wet-road braking distance estimate for the vehicles equipped with ABS (Anti-lock Brake System). In order to effectively compute the interval-wise braking times and the resulting total braking distance, we divide the entire speed interval at braking into finite number of uniform sub-intervals and apply the energy conservation law to individual sub-intervals. The proposed method is based on a numerical-analytical approach such that the frictional energy loss of the patterned tire is computed by 3-D hydroplaning analysis while the other at the disc pad is analytically derived. The hydroplaning simulation is performed by generally coupling an Eulerian finite volume method and an explicit Lagrangian finite element method. The operation of ABS is numerically implemented by controlling the tire angular velocity such that the preset tire slip ratio on the wet road is maintained. Numerical results are presented to illustrative and verify the the proposed numerical estimate.

  7. Reliability in automotive ethernet networks

    DEFF Research Database (Denmark)

    Soares, Fabio L.; Campelo, Divanilson R.; Yan, Ying;

    2015-01-01

    This paper provides an overview of in-vehicle communication networks and addresses the challenges of providing reliability in automotive Ethernet in particular.......This paper provides an overview of in-vehicle communication networks and addresses the challenges of providing reliability in automotive Ethernet in particular....

  8. Automotive battery technology

    CERN Document Server

    Watzenig, Daniel

    2014-01-01

    The use of electrochemical energy storage systems in automotive applications also involves new requirements for modeling these systems, especially in terms of model depth and model quality. Currently, mainly simple application-oriented models are used to describe the physical behavior of batteries. This book provides a step beyond of state-of-the-art modeling showing various different approaches covering following aspects: system safety, misuse behavior (crash, thermal runaway), battery state estimation and electrochemical modeling with the needed analysis (pre/post mortem). All this different approaches are developed to support the overall integration process from a multidisciplinary point-of-view and depict their further enhancements to this process.

  9. Automotive systems engineering

    CERN Document Server

    Winner, Hermann

    2013-01-01

    This book reflects the shift in design paradigm in automobile industry. It presents future innovations, often referred as  “automotive systems engineering”.  These cause fundamental innovations in the field of driver assistance systems and electro-mobility as well as fundamental changes in the architecture of the vehicles. New driving functionalities can only be realized if the software programs of multiple electronic control units work together correctly. This volume presents the new and innovative methods which are mandatory to master the complexity of the vehicle of the future.

  10. The automotive transmission book

    CERN Document Server

    Fischer, Robert; Jürgens, Gunter; Najork, Rolf; Pollak, Burkhard

    2015-01-01

    This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors, and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles.

  11. Ultracapacitors for automotive applications

    Science.gov (United States)

    Ashtiani, Cyrus; Wright, Randy; Hunt, Gary

    In response to a growing consensus in the auto industry that ultracapacitors can potentially play a key role in the modern vehicle power distribution network, a task force was created at the United States Advanced Battery Consortium (USABC) to tackle issues facing the fledging industry. The task force embarked on first developing and establishing standards for performance and abuse tolerance of ultracapacitors in collaboration with the U.S. Department of Energy and National Labs. Subsequently, potential applications in the automotive industry were identified and a consensus requirement specification was drawn as a development guide for the industry.

  12. Developing of a software for determining advanced brake failures in brakes test bench

    Directory of Open Access Journals (Sweden)

    Hakan Köylü

    2016-08-01

    Full Text Available At present time, the brake test bench conducts the braking and suspension tests of front or rear axles and the test results are evaluated through one axle. The purpose of the brake testing system is to determine braking force and damping coefficient dissymmetry of one axle. Thus, this test system evaluates the performance of service brake, hand brake and suspension systems by considering separately front and rear axle dissymmetry. For this reason, the effects of different braking and damping forces applied by right and left wheels of both axles on braking performance of all vehicle are not determined due to available algorithm of the test bench. Also, the other brake failures are not occurred due to the algorithm of brake test system. In this study, the interface has been developed to determine the other effects of dissymmetry and the other brake failures by using the one axle results of brake test bench. The interface has algorithm computing the parameters according to the interaction between front and rear axles by only using measured test results. Also, it gives the warnings by comparing changes in the parameters with braking performance rules. Braking and suspension tests of three different vehicles have been conducted by using brake test bench to determine the performance of the algorithm. Parameters based on the axle interaction have been calculated by transferring brake test results to the interface and the test results have been evaluated. As a result, the effects of brake and suspension failures on braking performance of both axle and vehicle have been determined thanks to the developed interface.

  13. IDEAL BRAKE FORCE DISTRIBUTION BETWEEN THE AXLES OF THE TWO-AXLE VEHICLE SERVICE BRAKE APPLICATIONS

    Directory of Open Access Journals (Sweden)

    M. Podryhalo

    2015-07-01

    Full Text Available The obtained analytical expressions allow us to evaluate the stability of two-axle vehicles at various slowdowns. An analytical expression for calculating the ideal according to condition stability ensuring of a two-axle vehicle at service brake applications of brake force distribution allows to offer automatic control devices for brake force adjucement. With decellerationg growth of the two-axle vehicle at service braking the braking force acting on the front axle should decrease relative to the brake force on the rear axle.

  14. Analysis of Braking Characteristic for Tire Rotary-drum Machine%轮胎转鼓试验设备制动特性分析

    Institute of Scientific and Technical Information of China (English)

    鲍晓东; 侯勇; 张绍国

    2012-01-01

    制动系统是转鼓试验设备重要的安全部件,通过分析制动系统的材料属性,建立了制动系统的简化模型.对盘式制动器在不同制动压力下的紧急制动过程进行仿真模拟,深入分析了制动系统在不同工作负荷下制动装置摩擦表面的应力、温度场分布情况以及有效的制动时间.对比不同工况下的计算结果,得到了制动盘和刹车片的应力和温度场分布规律,并且分析了制动压力与制动时间之间的关系.结果表明制动压力越大,制动时间越短,但制动系统温升越明显,相关结论为指导设备制动系统参数的合理选定提供了理论依据.%Braking system is an important safety component for the rotating, drum test equipment, through the analysis on the material properties of the braking system, the model of braking system was es-tablishea\\Emergency braking process of the disc brake was simulated under different pressure,and then friction surface stress, temperature field distribution and effective braking time of brake system in different workload stress were further analyzedAccording to the calculation results ,stress and temperature field distribution for braking disc and pad were obtained,and relationship between braking pressure and braking time was analyzed.The results show that as the braking pressure enhanced, the braking time is shorter,however, the temperature rise for braking system is more obvious.Conclusion provides a theoretical basis for brake system rational parameter selection.

  15. INTEGRATED AUTOMOTIVE MANUFACTURING SUPPLY

    Directory of Open Access Journals (Sweden)

    P.J.S. Van Dyk

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Supply planning and traffic flow planning are major activities in the automotive manufacturing environment worldwide. Traditionally, the impact of supply planning strategies on plant traffic is rarely considered. This paper describes the development of a Decision Support System (DSS that will assist automotive manufacturers to analyse the effect of supply planning decisions on plant traffic during the supply planning phase of their logistics planning process. In essence, this DSS consists of a Supply Medium Decision Support Tool (SMDST (an interactive MS-Excel model with Visual Basic interfacing and a traffic flow simulation model tool (using eMPlant simulation software.

    AFRIKAANSE OPSOMMING: Verskaffingsbeplanning en verkeersvloeibeplanning is belangrike aktiwiteite in die motorvervaardigingsbedryf wêreldwyd. Tradisioneel word die uitwerking van verskaffings-beplanningsstrategië op aanlegverkeer selde in ag geneem. Hierdie artikel beskryf die ontwikkeling van ’n Besluitnemings Ondersteuningstelsel (DSS wat motorvervaardigers sal ondersteun in die analise van die effek van verskaffingsbeplanningbesluite op aanlegverkeer tydens die verskaffingsbeplanningsfase van hulle logistieke beplanningsproses. Hierdie DSS bestaan hoofsaaklik uit ’n Verskaffings-vervoermiddel Besluitnemingshulpmiddel (SMDST (’n interaktiewe MS-Excel model met “Visual Basic” koppelling asook ’n simulasiemodel van verkeersvloei (met eM-Plant simulasiesagteware.

  16. 提升机盘形闸摆动分析及其检测技术%Analysis on swing of disk brakes of hoists and its detection technology

    Institute of Scientific and Technical Information of China (English)

    樊兆峰

    2011-01-01

    In view of great error in detecting clearance of the disk brake of the hoist in collieries, the fault operating status of swinging disk brakes is proposed. After the analysis on the working principle of the disc brake, main swing causes of the disc brake are pointed out, and the parameter A indicating swing amplitude of the disc brake is defined. In addition, after the detection system being designed, the swing of the disc brake is tested, and the variation curve of brake shoe position with the time is offered. The detection technology offers references for the repair and maintenance of the disc brake, and is beneficial to the safe operation of the hoisting system.%针对提升机盘形闸的闸间隙在检测中存在误差较大的问题,提出了盘形闸摆动的故障运行状态。通过对盘形闸工作原理的分析,指出了盘形闸摆动的主要原因,并定义了表征盘形闸摆动幅度的参数6。设计了检测系统,对盘形闸的摆动进行了测试,给出了闸瓦位置随时间的变化曲线。该检测技术对盘形闸的检修及维护提供了参考依据,有利于提升系统的安全运行。

  17. Brake Fluid Compatibility Studies with Advanced Brake Systems

    Science.gov (United States)

    2016-01-16

    identified as silane based compounds. Therefore, we can eliminate brake fluid polymerization as a possible cause since no siloxane based polymers were...cm-1 indicate presence of O-H peak corresponding UNCLASSIFIED DRAFT UNCLASSIFIED 21 to water ; 1631.50 cm-1 indicate presence of C=C peak...measurements are usually made using an auxiliary liquid with a known density. In this case, water is used as the auxiliary liquid. The weight of the o

  18. 49 CFR 393.49 - Control valves for brakes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Control valves for brakes. 393.49 Section 393.49... NECESSARY FOR SAFE OPERATION Brakes § 393.49 Control valves for brakes. (a) General rule. Except as provided..., which is equipped with power brakes, must have the braking system so arranged that one application...

  19. 49 CFR 393.41 - Parking brake system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Parking brake system. 393.41 Section 393.41... NECESSARY FOR SAFE OPERATION Brakes § 393.41 Parking brake system. (a) Hydraulic-braked vehicles...,536 kg (10,000 pounds) shall be equipped with a parking brake system as required by FMVSS No....

  20. 49 CFR 230.77 - Foundation brake gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  1. In-service hoisting machinery brake performance detection method research%在役起重机械制动器性能检测方法探究

    Institute of Scientific and Technical Information of China (English)

    巩建华; 丁克勤; 王磊; 朱传齐

    2015-01-01

    起重机在吊运过程中,起动和制动都很频繁,因此制动器是起重机上不可缺少的部件。本文通过分析制动器可能出现的一些故障,提出一种利用晶闸管及控制电路采集制动器性能参数来判断制动器的制动状态好坏的方法,该方法不仅能对制动器的故障进行诊断,还能防止制动器急刹给制动盘带来冲击,从而减少制动器的磨损,也减少了事故的发生。%The crane in the lifting process,starting and braking are very frequent,so the brake crane is an indispensable component.Some faults in this paper through the analysis of brake possible,put forward a kind oftube and a control circuit collection of brake performance parameters to judge the quality of the brake braking method of state using thyristor, the method of fault on the brake can be used not only for diagnosis,but also can prevent the brake brakes brought the impact for the brake disc,thereby reducing the brake wear,but also reduce the the occurrence of the accident.

  2. Performance experiment of integrated system with car electromagnetic and frictional brakes%轿车电磁制动与摩擦制动集成系统的性能试验

    Institute of Scientific and Technical Information of China (English)

    刘存香; 何仁; 胡春花

    2012-01-01

    At the test bench of integrated system with electromagne-tic and frictional brakes, the blend brake torque comparison was conducted with various air gap, maximum supplying current, electromagnetic brake coil turns and brake disc material. The relationship among blend brake torque, electromagnetic brake torque and frictional brake torque, and the influence of different parameters on the blend brake torque were investigated. The results show that air gap, supplying current of electromagnetic brake coil, electromagnetic brake coil turns and brake disc material all have influences on the total torque of integrated system. With consideration of two factors of performance and installation, the optimum air gap and maximum supplying current of electromagnetic brake coil are 2 mm and 15 A with electromagnetic brake coil turns of 820 x4 for copper brake disc. For those vehicles with gross mass more than 1 200 kg, the maximum supplying current of electromagnetic brake coil can be increased to 25 A.%利用所研制的电磁制动与摩擦制动集成系统试验台,进行了不同空气间隙、不同最大通电电流、不同电磁制动器线圈匝数以及不同制动盘材料时的集成系统联合制动力矩对比试验,研究了联合制动力矩、电磁制动力矩与摩擦制动力矩三者关系以及各参数对电磁制动与摩擦制动集成系统的影响.结果表明:气隙、电磁线圈通电电流、电磁线圈匝数以及制动盘材料等均对集成系统总制动力矩大小造成影响;综合考虑性能、安装2方面因素,可以选择的参数为气隙2 mm,电磁制动器线圈的最大通电电流为15 A,电磁线圈匝数为820×4,制动盘材料采用铜材质;对于整车总质量超过1200 kg的车辆,线圈最大通电电流可以增大至25 A.

  3. Design and Analysis of a Novel Centrifugal Braking Device for a Mechanical Antilock Braking System.

    Science.gov (United States)

    Yang, Cheng-Ping; Yang, Ming-Shien; Liu, Tyng

    2015-06-01

    A new concept for a mechanical antilock braking system (ABS) with a centrifugal braking device (CBD), termed a centrifugal ABS (C-ABS), is presented and developed in this paper. This new CBD functions as a brake in which the output braking torque adjusts itself depending on the speed of the output rotation. First, the structure and mechanical models of the entire braking system are introduced and established. Second, a numerical computer program for simulating the operation of the system is developed. The characteristics of the system can be easily identified and can be designed with better performance by using this program to studying the effects of different design parameters. Finally, the difference in the braking performance between the C-ABS and the braking system with or without a traditional ABS is discussed. The simulation results indicate that the C-ABS can prevent the wheel from locking even if excessive operating force is provided while still maintaining acceptable braking performance.

  4. Friction Wear Property of Brake Materials by Copper-based Powder Metallurgy With Various Brake Speeds

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-xiu; GAO Hong-xia; WEI Xiu-lan

    2004-01-01

    The experiment is conducted on MM-1000 friction test machine, which tests friction wear property of copper-based brake materials by powder metallurgy at different brake speeds. It shows that the coefficient of friction and wear volume are greatly influenced by brake speed. When the brake speed is 4000 r/min, which is a bit higher, the material still has a higher coefficient of friction with 0.47. When the brake speed is over 4000r/min, the coefficient of friction decreased rapidly. When the brake speed is 3000r/min, the material's wear is in its minimum. That is to say no matter how higher or lower the brake speed is the wear volume is bigger relatively. With the brake speed of the lower one it mainly refers to fatigue wear; while of higher one it mainly refers to abradant and oxidation wear.

  5. Dynamos in accretion discs

    OpenAIRE

    Brandenburg, A.; von Rekowski, B.

    2007-01-01

    It is argued that accretion discs in young stellar objects may have hot coronae that are heated by magnetic reconnection. This is a consequence of the magneto-rotational instability driving turbulence in the disc. Magnetic reconnection away from the midplane leads to heating of the corona which, in turn, contributes to driving disc winds.

  6. Enhanced test methods to characterise automotive battery cells

    Science.gov (United States)

    Mulder, Grietus; Omar, Noshin; Pauwels, Stijn; Leemans, Filip; Verbrugge, Bavo; De Nijs, Wouter; Van den Bossche, Peter; Six, Daan; Van Mierlo, Joeri

    This article evaluates the methods to characterise the behaviour of lithium ion cells of several chemistries and a nickel metal hydride cell for automotive applications like (plug-in) hybrid vehicles and battery electric vehicles. Although existing characterisation test methods are used, it was also indicated to combine test methods in order to speed up the test time and to create an improved comparability of the test results. Also, the existing capacity tests ignore that cells can be charged at several current rates. However, this is of interest for, e.g. fast charging and regenerative braking. Tests for high power and high energy application have been integrated in the enhanced method. The article explains the rationale to ameliorate the test methods. The test plan should make it possible to make an initial division in a group of cells purchased from several suppliers.

  7. Braking, Wheeled Vehicles. Test Operations Procedure (TOP)

    Science.gov (United States)

    2008-05-20

    shields removed, inspect the internal brake components, perform a camshaft rotation test and record the measurement obtained. c. If with non-removable...preceding 24 months, perform a camshaft rotation test and record the measurement. (2) When proof of wheel removal is not provided, remove brake drum(s...adjustment. Reject the vehicle if: • The adjustment is not within the manufacturer’s specifications. 15. Brake Camshafts Procedure: With

  8. Dynamics of Braking Vehicles: From Coulomb Friction to Anti-Lock Braking Systems

    Science.gov (United States)

    Tavares, J. M.

    2009-01-01

    The dynamics of braking of wheeled vehicles is studied using the Coulomb approximation for the friction between road and wheels. The dependence of the stopping distance on the mass of the vehicle, on the number of its wheels and on the intensity of the braking torque is established. It is shown that there are two regimes of braking, with and…

  9. BRAKE TEST OF SiCp/A356 BRAKE DISK AND INTERPRETATION OF EXPERIMENTAL RESULTS

    Institute of Scientific and Technical Information of China (English)

    YANG Zhiyong; HAN Jianmin; LI Weijing; WANG Jinhua

    2007-01-01

    Material properties are obvious different between aluminum matrix composites and iron and steel materials. After the brake disk braked at the same speed, the average temperature of the aluminum brake disk is 1.5 times as high as one of iron and steel brake disk, the thermal expansion value of the aluminum brake disk is 2 times as big as one of iron and steel brake disk. Mechanical property of the material decreases with the temperature increasing generally during braking, on the other hand, the big thermal stress in the brake disk happens because the material expansion is constrained. Firstly, the reasons of the thermal stress generation and the fracture failure of brake disks during braking are analyzed qualitatively by virtue of three-bar stress frame and sandwich deformation principles in physic, and then the five constraints which cause the thermal stress are summarized. On the base of the experimental results on the 1:1 emergency brake test, the thermal stress and temperature fields are simulated; The behavior of the fracture failure is interpreted semi-quantitatively by finite element analysis. There is the coincident forecast for the fraction position in term of the two methods. In the end, in the light of the analysis and calculation results, it is the general principles observed by the structure design and assembly of the brake disk that are summarized.

  10. Verification of pneumatic railway brake models

    Science.gov (United States)

    Piechowiak, Tadeusz

    2010-03-01

    The article presents a survey of diverse methods for validation of pneumatic train brake modelling. Various experimental measurements of railway pneumatic brakes were made chiefly on a test stand at Poznań University of Technology; other test stands and some results have been taken from the literature. The measurements, some of them unconventional, were performed on separate pneumatic elements, brake devices, the brake pipe and fragments thereof. Mechanical devices were also included. The experimental measurement results were used for the verification of numerical models and for the determination of parameters. The latter was partially performed using an optimisation method.

  11. REPORT on the TRUCK BRAKE LINING WORKSHOP and FLEET OPERATORS' SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.J.

    2003-02-03

    The report summarizes what transpired during brake linings-related workshop held at the Fall 2003 meeting of the Technology and Maintenance Council (TMC) in Charlotte, NC. The title of the workshop was ''Developing a Useful Friction Material Rating System''. It was organized by a team consisting of Peter Blau (Oak Ridge National Laboratory), Jim Britell (National Highway Traffic Safety Administration), and Jim Lawrence (Motor and Equipment Manufacturers Association). The workshop was held under the auspices of TMC Task Force S6 (Chassis), chaired by Joseph Stianche (Sanderson Farms, Inc.). Six invited speakers during the morning session provided varied perspectives on testing and rating aftermarket automotive and truck brake linings. They were: James R. Clark, Chief Engineer, Foundation Brakes and Wheel Equipment, Dana Corporation, Spicer Heavy Axle and Brake Division; Charles W. Greening, Jr, President, Greening Test Labs; Tim Duncan, General Manager, Link Testing Services;Dennis J. McNichol, President, Dennis NationaLease; Jim Fajerski, Business Manager, OE Sales and Applications Engineering, Federal Mogul Corporation; and Peter J. Blau, Senior Materials Development Engineer, Oak Ridge National Laboratory. The afternoon break-out sessions addressed nine questions concerning such issues as: ''Should the federal government regulate aftermarket lining quality?''; ''How many operators use RP 628, and if so, what's good or bad about it?''; and ''Would there be any value to you of a vocation-specific rating system?'' The opinions of each discussion group, consisting of 7-9 participants, were reported and consolidated in summary findings on each question. Some questions produced a greater degree of agreement than others. In general, the industry seems eager for more information that would allow those who are responsible for maintaining truck brakes to make better, more informed choices

  12. 风电制动器的热-结构耦合分析%Analvsis of the thermal-structural coupling for the brake of wind-turbine generation

    Institute of Scientific and Technical Information of China (English)

    董惠敏; 孙守林; 王新波

    2012-01-01

    针对制动器紧急制动时制动盘的旋转运动规律,根据风电制动器的实际结构和热传导的基本理论,建立了制动盘的温度场的数值模型,提出了循环迭代的计算方法,并用ANSYS有限元软件模拟了制动盘的温度场.将温度场中的热单元转化成结构单元实现热-结构的间接耦合,采用184单元刚性梁特性来带动制动盘转动,从而来模拟制动盘的减速运动,在充分考虑温度场和应力场的耦合关系的情况下,提出了分步加载的方法来计算制动盘的应力场.模拟结果表明:制动盘摩擦区域的点的等效应力分布与其温度场的分布基本一致.%Specific to the rotating law of brake disc in emergently braking, according to actual structure of wind power brake as well as the theory of heat transfer,a numerical model of temperature field for the brake disc is established,and a calculation method of iterative is presented;with ANSYS finite element software the brake disc temperature field is simulated to convert the thermal unit in temperature field into structural unit to achieve the indirect coupling of thermal-structure.Meanwhile by adopting the 184 unit with rigid beam feature the rotating disc is driven to rotate the brake disc in order to simulate the decreasing of the braking disc.Therefore a method of step by step loading is presented to calculate the stress field of the braking disc in fully considering the coupling relationship of the temperature field and stress field.The simulation results show that the equivalent stress distribution of the point at the friction area of the brake disc is basically consistent with its temperature field distribution.

  13. A double modal synthesis approach for brake squeal prediction

    Science.gov (United States)

    Monteil, M.; Besset, S.; Sinou, J.-J.

    2016-03-01

    This paper is devoted to propose a new efficient reduction method for predicting the stability analysis of a brake system subjected to friction-induced vibration. The finite element brake system under study is composed of a disc and a pad. The contact is modeled by introducing contact elements at the friction interface with the classical Coulomb law and a constant friction coefficient. It will be demonstrated that it is possible to build efficient reduced finite element models by developing a reduced model based on a Double Modal Synthesis (i.e. a classical modal reduction via Craig & Bampton plus a condensation at the frictional interface). Special attention is being conducted to validate the convergence of the reduced model especially on the approximation of the unstable modes with respect to real and imaginary parts. This complete numerical strategy based on Double Modal Synthesis allows us to perform relevance squeal prediction of unstable vibration modes. It is demonstrated that the numerical results via the Double Modal Synthesis are in good agreement with those of the classical Craig & Bampton method.

  14. Analysis and Design of Circular Plate MR Fluids Brake

    Institute of Scientific and Technical Information of China (English)

    Yang Yan; Lin Chang-Hua; Li Hui; Zhou Jing

    2004-01-01

    A magnetorheological (MR) fluids brake is a device to achieve brake by shear force of MR fluids. A MR rotary brake has the property that its braking torque changes quickly in response to an external magnetic field. In this study, the design method of the circular plate MR fluids brake is investigated theoretically. The equation of the torque transmitted by the MR fluids in the brake is derived to provide the theoretical foundation in the design of the brake. Based on this equation, after mathematically manipulated, the calculations of the volume, thickness and width of the MR fluids within the circular plate MR fluids brake are yield.

  15. Brake caliper with offset pads: Innovative brake technology for commercial vehicles offers opportunities to reduce weight and cost; Bremssattel mit tangential versetzten Bremsbelaegen: Innovative Radbremsentechnologie fuer Nutzfahrzeuge bietet neue Moeglichkeiten zur Gewichts- und Kostenreduzierung

    Energy Technology Data Exchange (ETDEWEB)

    Antony, P.; Blatt, P. [WABCO Radbremsen GmbH, Mannheim (Germany)

    2005-07-01

    Continuous optimizations and technical improvements showed no further potential for cost and weight reductions on basis of the conventional technique of a sliding caliper and two supported pads in the carrier. Additionally, global and technical needs are growing. With its 4th generation of air disc brakes and a new caliper concept, WABCO accounts to these developments. Characteristically for the New Generation (NG) is the caliper concept with pad offset in circumferential direction. This presentation describes construction and basics of the system, shows the usage of FEM and elements of Bionic methods and proofs its effectiveness with test bench results. Additional potential for the design of a new interfaces between brake and axle are identified. A significant improved disc cracking behavior offers possibilities for additional cost and weight savings. (orig.)

  16. Electronic Brake-Force Distribution Control Methods of ABS-Equipped Vehicles During Cornering Braking

    Institute of Scientific and Technical Information of China (English)

    WANG Guo-ye; LIU Zhao-du; MA Yue-feng; QI Zhi-quan

    2007-01-01

    Based on the dynamics of ABS-equipped vehicles during cornering braking,the electronic brakeforce distribution (EBD) control methods of ABS-equipped vehicles during cornering braking are proposed.According to the dynamics and the tire model under tire adhesion limit,the stability acceptance criteria of vehicles during cornering braking are proposed.According to the stability acceptance criteria and the ABS control,the EBD control methods of ABS-equipped vehicles during cornering braking are implemented by adjusting the threshold values of tires slip independently.The vehicle states during cornering braking at two typical initial velocities of the vehicle are analyzed by the EBD control methods,whose results indicate the EBD control methods can improve the braking performances of the vehicle during cornering braking comparing with the ABS control.

  17. MEMS for automotive and aerospace applications

    CERN Document Server

    Kraft, Michael

    2013-01-01

    MEMS for automotive and aerospace applications reviews the use of Micro-Electro-Mechanical-Systems (MEMS) in developing solutions to the unique challenges presented by the automotive and aerospace industries.Part one explores MEMS for a variety of automotive applications. The role of MEMS in passenger safety and comfort, sensors for automotive vehicle stability control applications and automotive tire pressure monitoring systems are considered, along with pressure and flow sensors for engine management, and RF MEMS for automotive radar sensors. Part two then goes on to explore MEMS for

  18. 14 CFR 27.735 - Brakes.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Landing Gear § 27.735 Brakes. For rotorcraft with wheel-type landing gear, a braking device must be installed that is— (a) Controllable by the pilot... torque when starting or stopping the rotor; and (2) Hold the rotorcraft parked on a 10-degree slope on...

  19. 14 CFR 29.735 - Brakes.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Landing Gear § 29.735 Brakes. For rotorcraft with wheel-type landing gear, a braking device must be installed that is— (a) Controllable by the... torque when starting or stopping the rotor; and (2) Hold the rotorcraft parked on a 10-degree slope on...

  20. Method and apparatus for electromagnetically braking a motor

    Science.gov (United States)

    Davis, Donald R. (Inventor); Radford, Nicolaus A (Inventor); Permenter, Frank Noble (Inventor); Parsons, Adam H (Inventor); Mehling, Joshua S (Inventor)

    2011-01-01

    An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied the permanent magnet moves the brake pad into frictional engagement with a housing, and when released the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage to a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller.

  1. Research on temperature rise of hoisting machine disk brake

    Institute of Scientific and Technical Information of China (English)

    MA Jun; JANG Hai-bo

    2012-01-01

    A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake system was constructed,limit conditions were defined,and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software.By analyzing the calculation results,the law of temperature change of surface of brake disk and shoes during the braking process was found.The law of brake shoes surface temperature distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s,1.0 s and 1.5 s was analyzed.A hoisting machine emergent braking test was carried out.Finally,the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.

  2. Automotive powerplant evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Stamper, K.R.

    1976-06-01

    A program to obtain automotive engine performance data for use in estimating vehicle emission and fuel economy in varied service and duty is described. An experimental test procedure for generating fuel consumption and emissions data adequate to characterize an engine over its full operating range was developed for steady-state tests. The development of a test procedure for transient testing is currently under way. The steady-state data will be collected from approximately 23 different engines, including: (1) 16 current production spark-ignition engines; (2) 3 pre-production or prototype advanced design spark-ignition engines; and (3) 4 light-duty diesel engines which are, or could be, used in passenger car applications. To date, steady-state ''engine maps'' were completed on 10 engines. A simplified model used to compare steady-state data with chassis dynamometer data indicates that results thus far can be used to obtain estimates of fuel economy in automobiles.

  3. Application of eddy current braking for the railway marshaling yard hu mp hu mping speed braking%涡流制动技术在铁路驼峰调节溜放速度的应用研究

    Institute of Scientific and Technical Information of China (English)

    侯忠馨; 王庆贤; 祝曦; 司徒国强

    2015-01-01

    Eddy -current braking is a kind of technology which utilizes electromagnet solenoid coils to generate electromagnetic fields.Rotating conductor cuts magnetic field lines to generate eddy current,and then generate a braking force.Eddy current braking is a new approach to take place of the original reduction gear device which had been used in the railway marshaling yard hump humping speed braking.Considering a low -noise,no me-chanical impact and friction,maintence free,low carbon environmental protection and other factors,eddy current reduction is an ideal new technology for hump humping deceleration and braking.The formulas of disc braking torque of eddy current braking were deduced on the basis of the theory of electromagnetic field.The formulas re-flect the relationship between the different design parameters of disc eddy current braking and can be used for the design and performance analysis of the eddy current braking structure.%涡流制动技术是利用电磁线圈产生电磁场,旋转导体在磁场中切割磁力线产生电涡流,从而产生制动力。所以涡流制动是替代铁路编组场驼峰溜放调速制动原有机械减速装置的新方法。考虑低噪声、无机械撞击与摩擦、免维护、低碳环保等因素,涡流减速是一种理想的驼峰溜放车列减速制动新技术。运用电磁场理论推导出盘形涡流制动装置的制动力矩计算公式,计算公式反映盘形涡流制动器各设计参数之间的相互关系,可用于盘形涡流制动器结构设计和性能分析的参考。

  4. Black hole accretion discs

    CERN Document Server

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. outbursting black-hole low-mass X-ray binaries. We then turn to the role of advection in accretion flow onto black holes illustrating its action and importance with a toy model describing both ADAFs and slim discs. We conclude with a presentation of the general-relativistic formalism describing accretion discs in the Kerr space-time.

  5. MHD disc winds

    CERN Document Server

    Ferreira, J

    2006-01-01

    This is a doctorate level lecture on the physics of accretion discs driving magnetically self-confined jets, usually referred to in the literature as disc winds. I will first review the governing magnetohydrodynamic equations and then discuss their physical content. At that level, necessary conditions to drive jets from keplerian accretion discs can already be derived. These conditions are validated with self-similar calculations of accretion-ejection structures. In a second part, I will critically discuss the biases introduced when using self-similarity as well as some other questions such as: Are these systems really unstable? Can a standard accretion disc provide the conditions to launch jets in its innermost parts? What is the difference between X-winds and disc-winds? Finally, the magnetic interaction between a protostar and its circumstellar disc will be discussed with a focus on stellar spin down.

  6. Black hole accretion discs

    OpenAIRE

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. ou...

  7. Escalation Practices in Automotive Development

    Directory of Open Access Journals (Sweden)

    Tomaž Jurejevčič

    2016-12-01

    Full Text Available Research Question (RQ: In automotive business many risk-involved situations occur and when detected, an escalation process takes place. Although defined and controlled by process guidelines and being supported by experts, escalation brings increased emotional pressure and stress for parties involved. Do escalation processes in automotive industry maintain all implied challenges? Purpose: The purpose of the article is to present current status of escalation processes and gaps between theory and practice cases. Results of the analysis are recommendations of good engineering practice derived also from actual experiences and learned lessons. Method: The method involves analysis of practical cases from automotive development process, lessons learned, anonymous survey of automotive engineers and classification of experiences. Results: Results of the survey have shown that the controlled escalation process for know-how related escalations is needed in order to establish the environment where the team is able to provide new, sometimes unconventional ideas for the problem to be solved. Organization: Presented recommendations and measures enable organization and managers to put the expertise and experiences of employees into action for problem solving during escalation. Originality: In this article some practices are presented that, although simple and some yet seen, with proper adjustment stemming from real life processes give a fruitful settlement of escalations in automotive development business.

  8. What brakes the Crab pulsar?

    CERN Document Server

    Čadež, A; Barbieri, C; Calvani, M; Naletto, G; Barbieri, M; Ponikvar, D

    2015-01-01

    Optical observations provide convincing evidence that the optical phase of the Crab pulsar follows the radio one closely. Since optical data do not depend on dispersion measure variations, they provide a robust and independent confirmation of the radio timing solution. The aim of this paper is to find a global mathematical description of Crab pulsar's phase as a function of time for the complete set of published Jodrell Bank radio ephemerides (JBE) in the period 1988-2014. We apply the mathematical techniques developed for analyzing optical observations to the analysis of JBE. We break the whole period into a series of episodes and express the phase of the pulsar in each episode as the sum of two analytical functions. The first function is the best-fitting local braking index law, and the second function represents small residuals from this law with an amplitude of only a few turns, which rapidly relaxes to the local braking index law. From our analysis, we demonstrate that the power law index undergoes "inst...

  9. Tribology of a Combined Yaw Bearing and Brake for Wind Turbines

    DEFF Research Database (Denmark)

    Poulios, Konstantinos

    A common goal among many countries worldwide is to increase the share of renewable energy in the overall energy supply. As response to such an aspiration, wind energy is becoming more and more cost effective through improved technology and increased size of wind turbines. One of the subsystems...... disc brake is typically included as an independent system. However, the increasing size of wind turbines makes roller element bearings an economically costly option. Moreover, the additional brake system increases complexity and consequently adds further production and maintenance costs. One...... that are affected by the tendency for building larger units, is the yaw system of horizontal axis wind turbines. State of the art wind turbine yaw systems consist of either a large roller element bearing or a corresponding segmented sliding bearing that connects the wind turbine nacelle and tower. An additional...

  10. The influence of high temperatures on the tribological properties of automotive friction materials

    Science.gov (United States)

    Savage, Luke

    Temperatures of over 800C can be generated at the frictional interface within the brake systems of large vehicles, such high temperatures result in severe wear at the frictional interface, and can also lead to a very dangerous condition known as brake fade, characterised by a sharp fall in the coefficient of friction between the pad and disc, resulting in a catastrophic loss of braking efficiency. Common friction materials are very specialised composites often containing up to 15 components bound together within a phenolic resin matrix. The high temperature behaviour of the various constituents of friction materials were investigated using thermogravimetric analysis, focusing in particular on the thermal decomposition of the phenolic resin matrix material, where it has been firmly established that the thermal decomposition products of phenolic resin are the primary cause of brake fade. This has lead to the development of a novel approach for reducing fade in conventional resin based friction materials, involving a partial carbonisation to 400C. The high temperature wear characteristics of both modified and conventional friction materials were examined using standard dynamometer tests, as well as a 'continuous drag' type test machine, equipped with a heating facility. During this study a number of factors were identified as the main influences on the overall wear behaviour of friction materials. These included test temperature, sample test history, and the various effects of friction films, which were the subject of a detailed analysis. The formation of friction films was found to be an important facet of a successful friction material, producing a reduction in wear at the frictional interface. Films were examined and analysed using EDX, SEM, and X-ray diffraction techniques, which revealed the presence of a high proportion of magnetite (Fe3O4), containing iron which originated from the disc surface. It was established that the incorporation of iron in friction

  11. An Experimental Analysis of Brake Efficiency Using Four Fluids in a Drum Brake System

    Directory of Open Access Journals (Sweden)

    Prince Owusu-Ansah

    2014-06-01

    Full Text Available This paper studies drum brake failure in Mini-buses using an experimental analysis to test the viscosities and the maximum braking force when different fluids such as clean, less dirty, dirty and soapy water solution were used in the braking system. The effects of each of these fluids when successive increments in pedal force were applied at hot and cold conditions for drum brakes were studied. The results of the Thepra Universal Brake Testing Equipment used for the braking efficiency test indicated that a pedal force of 110 kN produce a brake force of 0.61 kN for clean fluid, 0.56 kN for less dirty, 0.51 kN for dirty and 0.92 kN. The value of 0.92 kN which was achieved when the soapy water solution was used indicated a positive braking force and that soap water solution could be used to produce a high pedal force within a very short time (10-30 min and can therefore be used only in case of emergency. It was observed that the clean brake fluid gave the best braking force followed by the less dirty and finally the dirty brake fluid. In a situation where air has been trapped in the system under hot condition with or without a servo unit, clean brake fluid performed much better at least three times better than the other three fluids. For soap solution, braking was effective only when it was operated at cold condition but less effective when the system was hot. Soap solution is therefore not reliable when used for a very long time but effective only for emergency situations.

  12. Use of Fault Tree Analysis for Automotive Reliability and Safety Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, H

    2003-09-24

    Fault tree analysis (FTA) evolved from the aerospace industry in the 1960's. A fault tree is deductive logic model that is generated with a top undesired event in mind. FTA answers the question, ''how can something occur?'' as opposed to failure modes and effects analysis (FMEA) that is inductive and answers the question, ''what if?'' FTA is used in risk, reliability and safety assessments. FTA is currently being used by several industries such as nuclear power and chemical processing. Typically the automotive industries uses failure modes and effects analysis (FMEA) such as design FMEAs and process FMEAs. The use of FTA has spread to the automotive industry. This paper discusses the use of FTA for automotive applications. With the addition automotive electronics for various applications in systems such as engine/power control, cruise control and braking/traction, FTA is well suited to address failure modes within these systems. FTA can determine the importance of these failure modes from various perspectives such as cost, reliability and safety. A fault tree analysis of a car starting system is presented as an example.

  13. 49 CFR 570.55 - Hydraulic brake system.

    Science.gov (United States)

    2010-10-01

    ... parking brake and turn the ignition to start to verify that the brake system failure indicator lamp is... 49 Transportation 6 2010-10-01 2010-10-01 false Hydraulic brake system. 570.55 Section 570.55... 10,000 Pounds § 570.55 Hydraulic brake system. The following requirements apply to vehicles...

  14. 49 CFR 238.317 - Class II brake test.

    Science.gov (United States)

    2010-10-01

    ... locomotives that utilize an electric signal to communicate a service brake application and only a pneumatic... 49 Transportation 4 2010-10-01 2010-10-01 false Class II brake test. 238.317 Section 238.317... Requirements for Tier I Passenger Equipment § 238.317 Class II brake test. (a) A Class II brake test shall...

  15. 49 CFR 236.701 - Application, brake; full service.

    Science.gov (United States)

    2010-10-01

    ... developed. As applied to an automatic or electro-pneumatic brake with speed governor control, an application... 49 Transportation 4 2010-10-01 2010-10-01 false Application, brake; full service. 236.701 Section... § 236.701 Application, brake; full service. An application of the brakes resulting from a continuous...

  16. Integration of Gas Nitrocarburising and Oxidising in a Mass Production Line for Brake Pistons

    Institute of Scientific and Technical Information of China (English)

    Gero Walkowiak; Dieter M(u)ller; Uwe Zeibig

    2004-01-01

    The combination of wear- and corrosion resistance is a demand to a multitude of automotive parts. Several metallic coatings as hard/soft chromium or electroless nickel have been the conventional surface protection e.g. on parts as brake pistons and shock absorber or gas spring piston rods. The Corr-I-Dur(R) process - a special gasnitrocarburising and oxidising technology - has a huge potential not only in substituting those coatings but also in delivering surfaces with higher quality.The benefits of the replacement of soft chromium with Corr-I-Dur(R) and the implementation of the process in the customers production line with an annual capacity of 17 million brake pistons is described in this presentation. Starting with the demands on wear- and corrosion resistance the way of process development and the design of applicative equipment is shown. The result is a tailor-made surface solution with superior quality for deep drawn brake pistons. Two main disadvantagesoutgassing of the chromium layer and reduced corrosion resistance on the inner diameter - are eliminated by the replacement with Corr-I-Dur(R). The process-sure achievement of enhanced corrosion resistance, uniform layer thickness, negligible distortion as well as environmental and economical advantages make Corr-I-Dur(R) an excellence choice for this application.

  17. Improvement of Brake System of XJ-650 Workover Rig%XJ-650型修井机绞车制动系统改进

    Institute of Scientific and Technical Information of China (English)

    赵有清

    2015-01-01

    The working principle of hydraulic disc brake system of the hydraulic disc brake system is described in this paper.The problem of the existence of the pneumatic control belt brake for the XJ-650 type of the well is put forward.The hydraulic disc brake system of the workover rig is a-dapted for technological reformation,which is suitable for workover operation in deep and com-plex well conditions,and the construction of the labor intensity is decreased,security is obviously enhanced.%简述了修井机液压盘式刹车系统的工作原理。指出现有 XJ-650型修井机的气控带式刹车存在的问题。采用液压盘式刹车系统对该修井机进行技术改造,适应深井、复杂工况井等修井作业要求,并且使施工的劳动强度下降,安全性明显增强。

  18. Thermal analysis and temperature characteristics of a braking resistor for high-speed trains for changes in the braking current

    Science.gov (United States)

    Lee, Dae-Dong; Kang, Hyun-Il; Shim, Jae-Myung

    2015-09-01

    Electric brake systems are used in high-speed trains to brake trains by converting the kinetic energy of a railway vehicle to electric energy. The electric brake system consists of a regenerative braking system and a dynamic braking system. When the electric energy generated during the dynamic braking process is changed to heat through the braking resistor, the braking resistor can overheat; thus, failures can occur to the motor block. In this paper, a braking resistor for a high-speed train was used to perform thermal analyses and tests, and the results were analyzed. The analyzed data were used to estimate the dependence of the brake currents and the temperature rises on speed changes up to 300 km/h, at which a test could not be performed.

  19. WABCO Pneumatic Disk Brake%WABCO气压盘式制动器

    Institute of Scientific and Technical Information of China (English)

    罗鹏

    2009-01-01

    @@ 气压盘式制动器ADB(air disc brake)最早出现于20世纪90年代中期,能广泛应用于中重型车辆.它具有整体结构简单、重量轻、制动噪声小、散热快、制动间隙小以及维护简单等众多优于鼓式制动器的特点.

  20. 从制动副的摩擦磨损特性看陶瓷基刹车片的性能优势%The Performance Advantage of Ceramic Matrix Pods According to The Brake Pair Friction and Wear Characteristics

    Institute of Scientific and Technical Information of China (English)

    李云鹏; 邢记龙

    2011-01-01

    Automobile brake shoes material friction and wear characteristics influenced braking of safety, comfort and the replacement cycle.For the safety and reliabihty, people hope the braking deputy at high temperatures could still keep high friction coefficient (namely have enough brake friction torque). Based on the brake friction characteristics analysis and comparison, the brake deputy on the basic requirements were obtained. The good performance and development tendency of ceramic matrix pads were evaluted. The development of the automotive brake material ,plays a farreaching influence to our country.%汽车刹车片材料的摩擦磨损特性影响着车辆制动的安全性、舒适性与衬片的更换周期.从安全可靠性的角度来看,人们希望制动副在高温下仍能保持较高的摩擦系数(即有足够的制动摩擦力矩).通过对制动副摩擦磨损特性的分析,得出制动副对刹车片的基本要求,并对陶瓷基刹车片的性能优势和发展趋势作出评价,对我国汽车制动摩擦材料的发展起到了深远的影响.

  1. Hunting Plan Morgan Brake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan provides guidelines for administration of hunting activity and for development, maintenance, and enforcement of regulations and guidelines on Morgan Brake...

  2. Constraining the Braking Indices of Magnetars

    CERN Document Server

    Gao, Z F; Wang, N; Yuan, J P; Peng, Q H; Du, Y J

    2015-01-01

    Due to the lack of long term pulsed emission in quiescence and the strong timing noise, it is impossible to directly measure the braking index $n$ of a magnetar. Based on the estimated ages of their potentially associated supernova remnants (SNRs), we estimate the values of $n$ of nine magnetars with SNRs, and find that they cluster in a range of $1\\sim$41. Six magnetars have smaller braking indices of $13$ for other three magnetars are attributed to the decay of external braking torque, which might be caused by magnetic field decay. We estimate the possible wind luminosities for the magnetars with $13$ within the updated magneto-thermal evolution models. We point out that there could be some connections between the magnetar's anti-glitch event and its braking index, and the magnitude of $n$ should be taken into account when explaining the event. Although the constrained range of the magnetars' braking indices is tentative, our method provides an effective way to constrain the magnetars' braking indices if th...

  3. Compact Hybrid Automotive Propulsion System

    Science.gov (United States)

    Lupo, G.

    1986-01-01

    Power train proposed for experimental vehicle powered by internal combustion engine and electric motor. Intended for front-wheel drive automobile, power train mass produced using existing technology. System includes internal-combustion engine, electric motor, continuously variable transmission, torque converter, differential, and control and adjustment systems for electric motor and transmission. Continuously variable transmission integrated into hydraulic system that also handles power steering and power brakes. Batteries for electric motor mounted elsewhere in vehicle.

  4. Protostellar disc formation enabled by removal of small dust grains

    Science.gov (United States)

    Zhao, Bo; Caselli, Paola; Li, Zhi-Yun; Krasnopolsky, Ruben; Shang, Hsien; Nakamura, Fumitaka

    2016-08-01

    It has been shown that a realistic level of magnetization of dense molecular cloud cores can suppress the formation of a rotationally supported disc (RSD) through catastrophic magnetic braking in the axisymmetric ideal MHD limit. In this study, we present conditions for the formation of RSDs through non-ideal MHD effects computed self-consistently from an equilibrium chemical network. We find that removing from the standard MRN distribution the large population of very small grains (VSGs) of ˜ 10 Å to few 100 Å that dominate the coupling of the bulk neutral matter to the magnetic field increases the ambipolar diffusivity by ˜ 1-2 orders of magnitude at densities below 1010/cm-3. The enhanced ambipolar diffusion (AD) in the envelope reduces the amount of magnetic flux dragged by the collapse into the circumstellar disc-forming region. Therefore, magnetic braking is weakened and more angular momentum can be retained. With continuous high angular momentum inflow, RSDs of tens of au are able to form, survive, and even grow in size, depending on other parameters including cosmic ray ionization rate, magnetic field strength, and rotation speed. Some discs become self-gravitating and evolve into rings in our 2D (axisymmetric) simulations, which have the potential to fragment into (close) multiple systems in 3D. We conclude that disc formation in magnetized cores is highly sensitive to chemistry, especially to grain sizes. A moderate grain coagulation/growth to remove the large population of VSGs, either in the prestellar phase or during free-fall collapse, can greatly promote AD and help formation of tens of au RSDs.

  5. On the safety of braking mine up-haulage devices

    Energy Technology Data Exchange (ETDEWEB)

    Murzin, V.A.; Samusia, V.I.

    1982-01-01

    Experiments conducted on several mine up-haulage devices to analyze breakdowns due to the operator who quickly turned on the brake showed that sudden braking may really invoke maximum brake application on the machine winding much earlier than preventive braking and may lead to shutdown. It was concluded that in the Safety Regulations or Engineering Regulations that use of the handbrake should be more clearly outlined to preclude breakdown. One method of prevention is to develop and use a diagram showing build-up and magnitude of the braking moment when using the manual brake.

  6. 盘式制动器

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A parametric modelling approach for the preliminary design of automotive disc brakes;A predictive tool to evaluate disc brake squeal propensity-Part 3: parametric design studies;A predictive tool to evaluate disc brake squeal propensity-Part 2: system linearisation and modal analysis;A predictive tool to evaluate disc brake squeal propensity-Part 1: the model philosophy and the contact problem;A study of disc brake high frequency squeals and dis cin-plane/out-of-plane modes……

  7. Braking Index of Isolated Pulsars

    CERN Document Server

    Hamil, Oliver Q; Urbanec, Martin; Urbancova, Gabriela

    2016-01-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives that show unambiguously that the pulsars are slowing down. The commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of $\\Omega$. This relation leads to the power law $\\dot{\\Omega}$ = -K $\\Omega^{\\rm n}$ where $n$ is called the braking index. The MDR model predicts $n$ exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of $n$, individually accurate to a few percent or better, in the range 1$ <$ n $ < $ 2.8, which is consistently less than the predictions of the MDR model. In spite of an extensive investigation of various modifications of the MDR model, no satisfactory explanation of observation has been found yet. The aim of this work is t...

  8. Effect of Titanium on the Mechanical Properties and Microstructure of Gray Cast Iron for Automotive Applications

    Science.gov (United States)

    Gelfi, M.; Gorini, D.; Pola, A.; La Vecchia, G. M.

    2016-09-01

    Lamellar gray cast iron, with a mainly pearlitic microstructure, is widely used in the automotive industry, mostly in the manufacturing of brake disks. This work analyzes in depth the effects of small variations of titanium content on the microstructure and mechanical properties of cast iron brake disks. For this purpose, eight different heats of EN-GJL-250 cast iron were selected, with a similar chemical composition but with different titanium contents, varying from 0.013 to 0.031%. The drops in mechanical strength and hardness values measured on the high-Ti samples were correlated to microstructural variations quantitatively observed by means of optical and scanning electron microscope. It was found that titanium combines to form titanium nitrides, suppressing the beneficial microstructural effects of nitrogen at solidification. Residual nitrogen, if present in sufficient quantity, promotes the nucleation of primary austenite from the liquid and the formation of a fine microstructure, with small eutectic cells and lower graphite content. Such a microstructure provides brake disks with better mechanical properties. The interpretation of results was further supported by thermal analysis and thermodynamic calculations.

  9. Recycling used automotive oil filters

    Science.gov (United States)

    Peaslee, Kent D.

    1994-02-01

    Over 400 million used automotive oil filters are discarded in the United States each year, most of which are disposed of in landfills wasting valuable resources and risking contamination of ground- and surface-water supplies. This article summarizes U.S. bureau of Mines research evaluating scrap prepared from used automotive oil filters. Experimental results show that crushed and drained oil filters have a bulk density that is higher than many typical scrap grades, a chemical analysis low in residual elements (except tin due to use of tin plate in filters), and an overall yield, oil-filter scrap to cast steel, of 76% to 85%, depending on the method used to prepare the scrap.

  10. Antenna Arrays and Automotive Applications

    CERN Document Server

    Rabinovich, Victor

    2013-01-01

    This book throws a lifeline to designers wading through mounds of antenna array patents looking for the most suitable systems for their projects. Drastically reducing the research time required to locate solutions to the latest challenges in automotive communications, it sorts and systematizes material on cutting-edge antenna arrays that feature multi-element communication systems with enormous potential for the automotive industry. These new systems promise to make driving safer and more efficient, opening up myriad applications, including vehicle-to-vehicle traffic that prevents collisions, automatic toll collection, vehicle location and fine-tuning for cruise control systems. This book’s exhaustive coverage begins with currently deployed systems, frequency ranges and key parameters. It proceeds to examine system geometry, analog and digital beam steering technology (including "smart" beams formed in noisy environments), maximizing signal-to-noise ratios, miniaturization, and base station technology that ...

  11. GLOBAL PERSPECTIVES IN AUTOMOTIVE INDUSTRY

    Directory of Open Access Journals (Sweden)

    NICOLETA ISAC

    2010-01-01

    Full Text Available The automotive sector is characterised by a relatively low trade/salesratio. While the production of most automotive producers in the world is spread over variouscountries in the value chain, the brands are still considered to reflect some national identity.Internationalisation strategies may change over the lifecycle of the product and automakerstend to pursue diametrically opposed strategies. In mature markets, it is about managing whatgoes on beneath a static surface; in emerging markets’ dynamic environments, companies muststrategically position themselves to benefit from growth opportunities. However, without theright strategy and execution in mature markets, it is clear that traditional OEMs cannot profitfrom emerging markets-the persistence of structural issues in mature market operationseventually will rob all but the most resilient competitors of the opportunity to compete inemerging markets.

  12. Optimization of Tribological Properties of Nonasbestos Brake Pad Material by Using Steel Wool

    Directory of Open Access Journals (Sweden)

    R. Vijay

    2013-01-01

    Full Text Available The gradual phasing out of typical brake pad material led to the spark of extensive research in development of alternatives. Henceforth we have performed a tribological study to improve the performance characteristics of the friction product (brake pad by using steel wool, a metallic material which has an excellent structural reinforcement property and high thermal stability which are indeed required to improve the performance of the brake pad. Under the study, five frictional composites were developed and optimized using the same ingredients in an appropriate proportion except steel wool (0%, 4%, 8%, 12%, and 16% which is compensated by synthetic barite, and the synthesized compositions are designated as Na01 to Na05. The developed pads are tested for tribological behaviour under conventional environment in a standard pin on disc tribometer. It is observed that increase in steel wool concentration resulted in high coefficient of friction and low wear rate of pad as resulted in Na05 composition. SEM analysis of the wear surface has proved to be useful in understanding the wear behaviour of the composites.

  13. Rejuvenation of automotive fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu Seung; Langlois, David A.

    2016-08-23

    A process for rejuvenating fuel cells has been demonstrated to improve the performance of polymer exchange membrane fuel cells with platinum/ionomer electrodes. The process involves dehydrating a fuel cell and exposing at least the cathode of the fuel cell to dry gas (nitrogen, for example) at a temperature higher than the operating temperature of the fuel cell. The process may be used to prolong the operating lifetime of an automotive fuel cell.

  14. Effect of ZrSiO4 on the Friction Performance of Automotive Brake Friction Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Friction-wear properties of the ZrSiO4 reinforced samples were measured and compared with those of plain bronze based ones. For this purpose, density, hardness, friction coefficient wear behaviour of the samples were tested. Microstructures of samples before and after sintering and worn surfaces were also investigated by scanning electron microscopy (SEM), and the wear types were determined. The optimum friction-wear behaviour was obtained in the sample compacted at 500 MPa and sintered at 820℃. Density of the final samples decreased with increasing the amount of reinforcing elements (ZrSiO4) before pre-sintering. However after sintering, there is no change in density of the samples including reinforcing elements (ZrSiO4). With increasing friction surface temperature, a reduction in the friction coefficient of the samples was observed.However, the highest reductions in the friction coefficients were observed in the as-received samples containing 0,5% reinforced ZrSiO4. The SEM images of the sample indicated that while bronze-based break lining material without ZrSiO4 showed abrasive wear behaviour, increasing the amount of ZrSiO4 resulted a change in abrasive to adhesive wear mechanism. All samples exhibited friction-wear values, which were within the values shown in SAE-J661 standard. With increasing the amount of reinforcing ZrSiO4, wear resistance of the samples was increased. However samples reinforced with 5% and 6% ZrSiO4 showed the best results.

  15. Elemental composition of current automotive braking materials and derived air emission factors

    NARCIS (Netherlands)

    Hulskotte, J.H.J.; Roskam, G.D.; Denier van der Gon, H.A.C.

    2014-01-01

    Wear-related PM emissions are an important constituent of total PM emissions from road transport. Due to ongoing (further) exhaust emission reduction wear emissions may become the dominant PM source from road transport in the near future. The chemical composition of the wear emissions is crucial inf

  16. 49 CFR 232.609 - Handling of defective equipment with ECP brake systems.

    Science.gov (United States)

    2010-10-01

    ... conventional pneumatic brakes shall not move in a freight train operating in ECP brake mode unless it would otherwise have effective and operative brakes if it were part of a conventional pneumatic brake-equipped... pneumatic brakes shall not operate with freight cars equipped with stand-alone ECP brake systems unless:...

  17. Mapping automotive like controls to a general aviation aircraft

    Science.gov (United States)

    Carvalho, Christopher G.

    The purpose of this thesis was to develop fly-by-wire control laws enabling a general aviation aircraft to be flown with automotive controls, i.e. a steering wheel and gas/brake pedals. There was a six speed shifter used to change the flight mode of the aircraft. This essentially allows the pilot to have control over different aspects of the flight profile such as climb/descend or cruise. A highway in the sky was used to aid in the navigation since it is not intuitive to people without flight experience how to navigate from the sky or when to climb and descend. Many believe that general aviation could become as widespread as the automobile. Every person could have a personal aircraft at their disposal and it would be as easy to operate as driving an automobile. The goal of this thesis is to fuse the ease of drivability of a car with flight of a small general aviation aircraft. A standard automotive control hardware setup coupled with variably autonomous control laws will allow new pilots to fly a plane as easily as driving a car. The idea is that new pilots will require very little training to become proficient with these controls. Pilots with little time to stay current can maintain their skills simply by driving a car which is typically a daily activity. A human factors study was conducted to determine the feasibility of the applied control techniques. Pilot performance metrics were developed to compare candidates with no aviation background and experienced pilots. After analyzing the relative performance between pilots and non-pilots, it has been determined that the control system is robust and easy to learn. Candidates with no aviation experience whatsoever can learn to fly an aircraft as safely and efficiently as someone with hundreds of hours of flight experience using these controls.

  18. International Congress of Automotive and Transport Engineering

    CERN Document Server

    Ispas, Nicolae

    2017-01-01

    The volume will include selected and reviewed papers from CONAT - International Congress of Automotive and Transport Engineering to be held in Brasov, Romania, in October 2016. Authors are experts from research, industry and universities coming from 14 countries worldwide. The papers are covering the latest developments in automotive vehicles and environment, advanced transport systems and road traffic, heavy and special vehicles, new materials, manufacturing technologies and logistics, accident research and analysis and innovative solutions for automotive vehicles. The conference will be organized by SIAR (Society of Automotive Engineers from Romania) in cooperation with FISITA. .

  19. Electrically powered automotive vehicle with an energy recovering apppartus

    OpenAIRE

    Chevroulet, Tristan; Damminger, Ludwig

    1994-01-01

    Electrically driven motor vehicle, comprising mechanical means for braking the driving wheel and at least one electric motor. System for transfering brake energy into air-conditioning device. Enhances electro brake capabilities, provides controlled dissipation means, enables energy recovery & management. Improves accumulator lifetime (limits power surges due to braking). SMH - MCC Smart car concepts (electic & hybrid)

  20. The strength of the hybrid braking calipers analysis

    Institute of Scientific and Technical Information of China (English)

    Li Weitao; Yu Haiqing; Jiang Xiaoyan

    2015-01-01

    The braking system is an important part to ensure the safety of the vehicle, so the strength analysis is essential to the brake caliper. In this article, the forces will be mixed in the caliper brake systems theoretical analysis, and based on the actual working conditions established calipers ABAQUS finite element model to simulate calipers provide a theoretical basis for the structural design of the brake caliper.

  1. New Method of Road Surface Identification in Anti-Lock Braking System

    Institute of Scientific and Technical Information of China (English)

    QI Zhi-quan; LIU Zhao-du; ZHANG Jing-bo; MA Yue-feng

    2005-01-01

    Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock braking system (ABS) is proposed. According to the characteristics of vehicle-road dynamic model, a simple math resolution method of the model's factors is established. Only using the information of wheel speed, the vehicle reference velocity and the wheel slip ratio are estimated real-timely. And based on the wheel dynamic model, the road characteristic parameter is determined to identify the road surface for the determination of thresholds of ABS regulative parameters. With this new method, the road surface identification can be accurately obtained and calculation time is short that it can meet the ABS real time control need, and it also improves the performance of ABS.

  2. ACTIVE FRONT STEERING DURING BRAKING PROCESS

    Institute of Scientific and Technical Information of China (English)

    CHEN Deling; CHEN Li; YIN Chengliang; ZHANG Yong

    2008-01-01

    An active front steering (AFS) intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation (HILS) system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.

  3. Hillside, Morgans Brake, and Mathews Brake National Wildlife Refuges Deer Harvest Records are from 2008 and 2014

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These harvest data are from Hillside, Morgans Brake, and Mathews Brake NWRs during the 2008 and 2014 deer seasons. They measure weight, antler size, prevalence of...

  4. Biweekly Waterfowl Counts from Mathews Brake, Morgan Brake, and Hillside National Wildlife Refuges in 2001 and 2002

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Biweekly Waterfowl Counts from Mathews Brake, Morgan Brake, and Hillside National Wildlife Refuges conducted from October 2001 to February 2002

  5. Central Mississippi Refuges: Yazoo, Panther Swamp, Hillside, Morgan Brake & Bathews Brake: Annual narrative report: Calendar year 2001

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yazoo, Hillside, Panther Swamp, Morgan Brake, and Mathews Brake NWRs covers refuge activities during 2001. The report begins with a...

  6. The study on brake stabilization of vibration based on harmonic response of dynamic%基于动态谐反应的制动器振动稳定性研究

    Institute of Scientific and Technical Information of China (English)

    吴武辉; 潘亚军; 吕宗强

    2014-01-01

    基于制动器钳体结构特征,建立了制动器钳体部件振动瞬态分析模型。模型有限元分析表明了各部件间模态振动频率,揭示了制动过程发生制动尖叫的主要原因是制动钳体零件间某阶频率十分接近;基于制动钳体和制动盘的谐反应有限元分析,分析表明,改变制动器钳体设计参数可在一定程度上改善制动器稳定性,特别是当制动盘厚度参数改变时,对制动器的振动稳定性和噪声的影响很明显。%A new vibration transient analysis model of the brake components are established based on the structural feature of calip. The finite element analysis(FEA) of vibration frequency among parts shown that the main mechanism resulting from squealing frequency occurs at the case of the natural frequency between the two parts being near. Based on the research of harmonic response FEA between brake calip and brake disc, it is evident that braking stability can be improved by changing the construction parameter of brake components. The analysis also shows that within certain range, to change the design parameter of the calip body can improve the stability of braking system. Especially, the sta-bility and breaking noise of the brake can effectively improved by increasing the thickness size of brake disc.

  7. 49 CFR 238.319 - Running brake test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Running brake test. 238.319 Section 238.319... Requirements for Tier I Passenger Equipment § 238.319 Running brake test. (a) As soon as conditions safely permit, a running brake test shall be performed on each passenger train after the train has received,...

  8. 49 CFR 393.40 - Required brake systems.

    Science.gov (United States)

    2010-10-01

    ... motor vehicle must meet the applicable service, parking, and emergency brake system requirements....49, and 393.52 of this subpart. (c) Parking brakes. Each commercial motor vehicle must be equipped with a parking brake system that meets the applicable requirements of § 393.41. (d) Emergency...

  9. 49 CFR 238.309 - Periodic brake equipment maintenance.

    Science.gov (United States)

    2010-10-01

    ... that all of the equipment's brake system pneumatic components that contain moving parts and are sealed... 49 Transportation 4 2010-10-01 2010-10-01 false Periodic brake equipment maintenance. 238.309... Maintenance Requirements for Tier I Passenger Equipment § 238.309 Periodic brake equipment maintenance....

  10. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine... brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other similar...

  11. 49 CFR 229.57 - Foundation brake gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 229.57 Section 229.57 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Foundation brake gear. A lever, rod, brake beam, hanger, or pin may not be worn through more than 30...

  12. The braking indices in pulsar emission models

    CERN Document Server

    Wu, F; Gil, J; Gil, Janusz

    2003-01-01

    Using the method proposed in a previous paper, we calculate pulsar braking indices in the models with torque contributions from both inner and outer accelerating regions, assuming that the interaction between them is negligible. We suggest that it is likely that the inverse Compton scattering induced polar vacuum gap and the outer gap coexist in the pulsar magnetosphere. We include the new near threshold vacuum gap models with curvature-radiation and inverse Compton scattering induced cascades, respectively; and find that these models can well reproduce the measured values of the braking indices.

  13. Innervation of ''painful'' lumbar discs

    NARCIS (Netherlands)

    Coppes, MH; Marani, E; Thomeer, RTWM; Groen, GJ

    1997-01-01

    Study Design. The authors investigated the innervation of discographically confirmed degenerated and ''painful'' human intervertebral discs. Objective. To determine the type and distribution patterns of nerve fibers present in degenerated human intervertebral discs. Summary of Background Data. The i

  14. Automotive Thermoelectric Waste Heat Recovery

    Science.gov (United States)

    Meisner, Gregory P.

    2015-03-01

    Considerable fuel energy, as much as 70%, is not converted to useful work by internal combustion engines but is instead rejected as waste heat, and more than half of the waste heat, nearly 40% of fuel energy, is contained in vehicle exhaust gas. This provides an opportunity to recover some of the wasted fuel energy and convert it from heat into useful work, subject to the laws of thermodynamics, and thereby improve vehicle energy efficiency. Thermoelectric (TE) materials have been extensively researched and TE devices are now being developed for operation at high temperatures corresponding to automotive exhaust gases for direct solid-state conversion of heat into electricity. This has stimulated substantial progress in the development of practical TE generator (TEG) systems for large-scale commercialization. A significant enabler of this progress has been the US Department of Energy's Vehicle Technologies Program through funding for low cost solutions for automotive TE waste heat recovery to improve fuel economy. Our current project at General Motors has culminated in the identification of the potential supply chain for all components and assembly of an automotive TEG. A significant focus has been to develop integrated and iterative modeling tools for a fully optimized TEG design that includes all components and subsystems (TE modules, heat exchangers, thermal interfaces, electrical interconnects, power conditioning, and vehicle integration for maximal use of TEG power). We have built and tested a new, low-cost Initial TEG prototype based on state-of-the-art production-scale skutterudite TE modules, novel heat exchanger designs, and practical solutions to the many technical challenges for optimum TEG performance. We will use the results for our Initial TEG prototype to refine our modeling and design tools for a Final automotive TEG system prototype. Our recent results will be presented. Thanks to: J.R. Salvador, E.R. Gundlach, D. Thompson, N.K. Bucknor, M

  15. Hillside, Morgan Brake, and Mathews Brake National Wildlife Refuges Reforestation Plan for 1992-1996

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan addresses the history of reforestation at Hillside National Wildlife Refuge and its two satellite refuges, Morgan Brake National Wildlife Refuge and...

  16. Study on Braking Energy Regeneration System for City Bus

    Institute of Scientific and Technical Information of China (English)

    ZOU Zheng-yao; CHEN Ru-wen; YANG Xue-mei; LIU Gou-bing; JIN Jia-jun

    2011-01-01

    Braking of the urban vehicles of public service wastes a large number of engine energy in the condition of starting and stopping frequently. Aiming at the problem, an electro-mechanical braking energy regeneration system was proposed which adopted a high-speed flywheel and a battery to recover the braking energy and achieve the secondary traction for the auxiliary start function. The system strategy was designed and the braking simulation was processed to validate its feasibility. The experiment results show that the system can effectively recover the braking energy, improve the starting performance of the city bus and it can be applied to the engineering.

  17. BRAKING PROCESS OF ENDURO AND HIGHWAY-TOURIST MOTORBIKES

    Directory of Open Access Journals (Sweden)

    Paweł SKRZYPCZYK

    2015-06-01

    Full Text Available In the event of an emergency, head of the motorcycle has a split second to decide what to do defensive maneuver. The most common choice is the braking maneuver. Starting motorcycle braking is associated with the selection of additional brake, which uses a driver. It is here to choose to use the front brake, rear or both simultaneously. The paper presents the study of the effects of such decision on the braking process. Tests were carried out for enduro and highway-tourist motorbikes.

  18. How do accretion discs break?

    Science.gov (United States)

    Dogan, Suzan

    2016-07-01

    Accretion discs are common in binary systems, and they are often found to be misaligned with respect to the binary orbit. The gravitational torque from a companion induces nodal precession in misaligned disc orbits. In this study, we first calculate whether this precession is strong enough to overcome the internal disc torques communicating angular momentum. We compare the disc precession torque with the disc viscous torque to determine whether the disc should warp or break. For typical parameters precession wins: the disc breaks into distinct planes that precess effectively independently. To check our analytical findings, we perform 3D hydrodynamical numerical simulations using the PHANTOM smoothed particle hydrodynamics code, and confirm that disc breaking is widespread and enhances accretion on to the central object. For some inclinations, the disc goes through strong Kozai cycles. Disc breaking promotes markedly enhanced and variable accretion and potentially produces high-energy particles or radiation through shocks. This would have significant implications for all binary systems: e.g. accretion outbursts in X-ray binaries and fuelling supermassive black hole (SMBH) binaries. The behaviour we have discussed in this work is relevant to a variety of astrophysical systems, for example X-ray binaries, where the disc plane may be tilted by radiation warping, SMBH binaries, where accretion of misaligned gas can create effectively random inclinations and protostellar binaries, where a disc may be misaligned by a variety of effects such as binary capture/exchange, accretion after binary formation.

  19. Optic disc drusen

    DEFF Research Database (Denmark)

    Fledelius, Hans C

    2017-01-01

    , which, in view of the small disc at risk, may seem a paradox. METHODS: This is an observational retrospective study on an eye clinic series (n = 49), focusing on visual acuity, kinetic/static perimetry, and longitudinal trends, to include the question of eventual visual incapacity. RESULTS: Forty...

  20. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  1. A HIGH BRAKING INDEX FOR A PULSAR

    Energy Technology Data Exchange (ETDEWEB)

    Archibald, R. F.; Ferdman, R. D.; Kaspi, V. M.; Tendulkar, S. P. [Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montréal, QC H3A 2T8 (Canada); Gotthelf, E. V. [Columbia Astrophysics Laboratory, 550 West 120th Street, New York, NY 10027-6601 (United States); Guillot, S. [Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Harrison, F. A. [Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Pasadena, CA 91125 (United States); Keane, E. F. [SKA Organization, Jodrell Bank Observatory, Cheshire SK11 9DL (United Kingdom); Pivovaroff, M. J. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550-9234 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Tomsick, J. A. [Space Science Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720-7450 (United States)

    2016-03-01

    We present a phase-coherent timing solution for PSR J1640–4631, a young 206 ms pulsar using X-ray timing observations taken with NuSTAR. Over this timing campaign, we have measured the braking index of PSR J1640–4631 to be n = 3.15 ± 0.03. Using a series of simulations, we argue that this unusually high braking index is not due to timing noise, but is intrinsic to the pulsar's spin-down. We cannot, however, rule out contamination due to an unseen glitch recovery, although the recovery timescale would have to be longer than most yet observed. If this braking index is eventually proven to be stable, it demonstrates that pulsar braking indices greater than three are allowed in nature; hence, other physical mechanisms such as mass or magnetic quadrupoles are important in pulsar spin-down. We also present a 3σ upper limit on the pulsed flux at 1.4 GHz of 0.018 mJy.

  2. 30 CFR 57.14101 - Brakes.

    Science.gov (United States)

    2010-07-01

    ... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Machinery and Equipment Safety... equipped on self-propelled mobile equipment, parking brakes shall be capable of holding the equipment with... surface-operated equipment at underground mines when an MSHA inspector has reasonable cause to...

  3. Massive star models with magnetic braking

    CERN Document Server

    Meynet, Georges; Maeder, Andre

    2010-01-01

    Magnetic fields at the surface of a few early-type stars have been directly detected. These fields have magnitudes between a few hundred G up to a few kG. In one case, evidence of magnetic braking has been found. We investigate the effects of magnetic braking on the evolution of rotating ($\\upsilon_{\\rm ini}$=200 km s$^{-1}$) 10 M$_\\odot$ stellar models at solar metallicity during the main-sequence (MS) phase. The magnetic braking process is included in our stellar models according to the formalism deduced from 2D MHD simulations of magnetic wind confinement by ud-Doula and co-workers. Various assumptions are made regarding both the magnitude of the magnetic field and of the efficiency of the angular momentum transport mechanisms in the stellar interior. When magnetic braking occurs in models with differential rotation, a strong and rapid mixing is obtained at the surface accompanied by a rapid decrease in the surface velocity. Such a process might account for some MS stars showing strong mixing and low surfa...

  4. Asbestos free friction composition for brake linings

    Indian Academy of Sciences (India)

    Arnab Ganguly; Raji George

    2008-02-01

    An asbestos free friction material composite for brake linings is synthesized containing fibrous reinforcing constituents, friction imparting and controlling additives, elastomeric additives, fire retarding components and a thermosetting resin. The composite shows exemplary friction characteristics and has great resistance to wear and shows good temperature stability.

  5. Evolution of Protoplanetary Discs with Magnetically Driven Disc Winds

    CERN Document Server

    Suzuki, Takeru K; Morbidelli, Alessandro; Crida, Aurélien; Guillot, Tristan

    2016-01-01

    Aims: We investigate the evolution of protoplanetary discs (PPDs hereafter) with magnetically driven disc winds and viscous heating. Methods: We consider an initially massive disc with ~0.1 Msun to track the evolution from the early stage of PPDs. We solve the time evolution of surface density and temperature by taking into account viscous heating and the loss of the mass and the angular momentum by the disc winds within the framework of a standard alpha model for accretion discs. Our model parameters, turbulent viscosity, disc wind mass loss, and disc wind torque, which are adopted from local magnetohydrodynamical simulations and constrained by the global energetics of the gravitational accretion, largely depends on the physical condition of PPDs, particularly on the evolution of the vertical magnetic flux in weakly ionized PPDs. Results: Although there are still uncertainties concerning the evolution of the vertical magnetic flux remaining, surface densities show a large variety, depending on the combinatio...

  6. 新款三轮运动车制动系统设计%Design of Brake System of New Three-wheel Sports Car

    Institute of Scientific and Technical Information of China (English)

    田锐; 李桂华

    2012-01-01

    Through the braking performance analysis for new three-wheel sports car,the paper designed and calculated the structure of floating type disc brake in braking system and fully hydraulic braking drive system by human power.According to GB 7258-2004"safety specification for power-driven vehicles operating on road",its performance is verified,and the design result is good.And so the braking requirements of three-wheel sports car in ideal pavement is also met.%通过对新款三轮运动车制动性能要求进行分析,设计计算了制动系统的浮钳形盘式制动器结构和采用人力操纵的全液压制动驱动系统,并根据《机动车运行安全技术条件》(GB 7258-2004)进行了验证,达到了设计效果,满足了三轮运动车在理想路面上的制动要求。

  7. Automotive Battery Modelling and Management

    Directory of Open Access Journals (Sweden)

    N. M. Hammad

    2014-06-01

    Full Text Available The estimation of vehicle battery performance is typically addressed by testing the battery under specific operation conditions by using a model to represent the test results. Approaches for representing test results range from simple statistical models to neural networks to complex, physics-based models. Basing the model on test data could be problematical when testing becomes impractical with many years life time tests. So, real time estimation of battery performance, an important problem in automotive applications, falls into this area. In vehicles it is important to know the state of charge of the batteries in order to prevent vehicle stranding and to ensure that the full range of the vehicle operation is exploited. In this paper, several battery models have studied including analytical, electrical circuits, stochastic and electro- chemical models. Valve Regulated Lead Acid “VRLA” battery has been modelled using electric circuit technique. This model is considered in the proposed Battery Monitoring System “BMS”. The proposed BMS includes data acquisition, data analysis and prediction of battery performance under a hypothetical future loads. Based on these criteria, a microprocessor based BMS prototype had been built and tested in automotive Lab,. The tests show promising results that can be used in industrial applications

  8. Automotive stamped part fatigue design

    Directory of Open Access Journals (Sweden)

    Caudoux Mélanie

    2014-06-01

    Full Text Available Fatigue design of automotive axle parts is of prior concern because of these are high safety parts and they are expected to drive the overall vehicle mass reduction. In this framework, the stamping process is widely used to form axle parts, before assembling them by welding. Consequently, the mechanical and physical characteristics of the blank sheet are modified, having a strong influence on the fatigue behavior. In this paper, we address the consequences of the stamped process on the fatigue design and how they may be effectively taken into account in the automotive industry. Actually, the coupling between the stamping process and the fatigue design is under development at PSA Peugeot Citroën Company since several years. Such an analysis deals with some major topics: thickness variation, plastic hardening and deformation, and residual stress. All of these ingredients result in fatigue criteria evolutions: it is important to stress that the stamping process can have advantageous or disadvantageous consequences on the fatigue design. This is here highlighted on some examples, dealing with front and rear axles.

  9. Pedestrian injury mitigation by autonomous braking.

    Science.gov (United States)

    Rosén, Erik; Källhammer, Jan-Erik; Eriksson, Dick; Nentwich, Matthias; Fredriksson, Rikard; Smith, Kip

    2010-11-01

    The objective of this study was to calculate the potential effectiveness of a pedestrian injury mitigation system that autonomously brakes the car prior to impact. The effectiveness was measured by the reduction of fatally and severely injured pedestrians. The database from the German In-Depth Accident Study (GIDAS) was queried for pedestrians hit by the front of cars from 1999 to 2007. Case by case information on vehicle and pedestrian velocities and trajectories were analysed to estimate the field of view needed for a vehicle-based sensor to detect the pedestrians one second prior to the crash. The pre-impact braking system was assumed to activate the brakes one second prior to crash and to provide a braking deceleration up to the limit of the road surface conditions, but never to exceed 0.6 g. New impact speeds were then calculated for pedestrians that would have been detected by the sensor. These calculations assumed that all pedestrians who were within a given field of view but not obstructed by surrounding objects would be detected. The changes in fatality and severe injury risks were quantified using risk curves derived by logistic regression of the accident data. Summing the risks for all pedestrians, relationships between mitigation effectiveness, sensor field of view, braking initiation time, and deceleration were established. The study documents that the effectiveness at reducing fatally (severely) injured pedestrians in frontal collisions with cars reached 40% (27%) at a field of view of 40 degrees. Increasing the field of view further led to only marginal improvements in effectiveness.

  10. The brake-system of the new Mercedes van-generation Sprinter; Die Bremsanlage der neuen Transporter-Generation Sprinter von Mercedes-Benz

    Energy Technology Data Exchange (ETDEWEB)

    Reuter, M.; Spielmann, W.

    1996-01-01

    The new Mercedes-Sprinter is the first van model series in this weight category which is equipped with disc brakes all round and ABS und ABD as standard. A diagonally divided hydraulic brake system with vacuum-controlled power assistance and automatic load-sensitive brake pressure control (ALB) is installed. The wheel brakes used are of a floating caliper type. During the development particular attention was paid to the constant friction coefficient of the brake linings, the `high` speed suitability and the provision of high thermal reserves. This concept offers good prerequisites for adding additional functions such as a brake assistant or a dynamic handling control system. For the first time there was a close cooperation between vehicle manufacturer, suppliers of brakes, linings and components during the development phase. To organise this complex development work a comprehensive specification booklet with detailed specs was drawn up and agreed with all parties involved. The result of the close cooperation is a positive example of the Mercedes-Benz tandem philosophy. (orig.) [Deutsch] Beim neuen Mercedes-Sprinter handelt es sich um die erste Transporter-Baureihe in dieser Gewichtsklasse mit vier Scheibenbremsen und serienmaessigem ABS mit ABD. Zum Einsatz kommt eine diagonal aufgeteilte hydraulische Bremsanlage mit Vakuum-Hilfskraftunterstuetzung und automatisch lastabhaengiger Bremskraftregelung (ALB). Als Radbremsen werden Schwimmsattelbremsen in Faustsattelbauweise verwendet. Besondere Schwerpunkte bei der Entwicklung waren die Reibwertkonstanz der Bremsbelaege, die Tauglichkeit bei hohen Geschwindigkeiten und die Schaffung hoher thermischer Reserven. Mit dieser Konzeption sind gute Voraussetzungen geschaffen, um weitere Zusatzfunktionen wie etwa einen Bremsassistenten oder eine Fahrdynamikregelung einzusetzen. Bei der Entwicklung wurde erstmals eine enge Zusammenarbeit zwischen Fahrzeughersteller, Bremsen-, Belag- und Komponentenlieferanten praktiziert. Zur

  11. Counter-Rotating Accretion Discs

    OpenAIRE

    Dyda, Sergei; Lovelace, Richard V. E.; Ustyugova, Galina V.; Romanova, Marina M.; Koldoba, Alexander V.

    2014-01-01

    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the tw...

  12. Modeling and design of cooperative braking in electric and hybrid vehicles using induction machine and hydraulic brake

    Directory of Open Access Journals (Sweden)

    Zaini Dalimus

    2016-07-01

    Full Text Available In mixed-mode braking applications, the electric motor / generator (M/G and hydraulic pressure valve are controlled to meet the driver’s braking demand. Controlling these braking elements is achieved by modulating the current generated by the M/G and adjusting the fluid pressure to the wheel brake cylinders. This paper aims to model and design combined regenerative and hydraulic braking systems which, comprise an induction electric machine, inverter, NiMH battery, controller, a pressure source, pressure control unit, and brake calipers. A 15 kW 1500 rpm induction machine equipped with a reduction gear having a gear ratio of 4 is used. A hydraulic brake capable to produce fluid pressure up to 40 bar is used. Direct torque control and pressure control are chosen as the control criteria in the M/G and the hydraulic solenoid valve. The braking demands for the system are derived from the Federal Testing Procedure (FTP drive cycle. Two simulation models have been developed in Matlab®/Simulink® to analyze the performance of the control strategy in each braking system. The developed model is validated through experiment. It is concluded that the control system does introduce torque ripple and pressure oscillation in the braking system, but these effects do not affect vehicle braking performance due to the high frequency nature of pressure fluctuation and the damping effect of the vehicle inertia. Moreover, experiment results prove the effectiveness of the developed model.

  13. Excitation Method of Linear-Motor-Type Rail Brake without Using Power Sources by Dynamic Braking with Zero Electrical Output

    Science.gov (United States)

    Sakamoto, Yasuaki; Kashiwagi, Takayuki; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

    The eddy current rail brake is a type of braking system used in railway vehicles. Because of problems such as rail heating and problems associated with ensuring that power is supplied when the feeder malfunctions, this braking system has not been used for practical applications in Japan. Therefore, we proposed the use of linear induction motor (LIM) technology in eddy current rail brake systems. The LIM rail brake driven by dynamic braking can reduce rail heating and generate the energy required for self-excitation. In this paper, we present an excitation system and control method for the LIM rail brake driven by “dynamic braking with zero electrical output”. The proposed system is based on the concept that the LIM rail brake can be energized without using excitation power sources such as a feeder circuit and that high reliability can be realized by providing an independent excitation system. We have studied this system and conducted verification tests using a prototype LIM rail brake on a roller rig. The results show that the system performance is adequate for commercializing the proposed system, in which the LIM rail brake is driven without using any excitation power source.

  14. Vibration analysis of atomising discs

    Energy Technology Data Exchange (ETDEWEB)

    Deng, H; Ouyang, H, E-mail: H.Ouyang@liverpool.ac.u [Department of Engineering, University of Liverpool, Liverpool L69 3GH (United Kingdom)

    2009-08-01

    The centrifugal atomisation of metallic melts using a spinning disc is an important process for powder production and spray deposition. In the manufacturing process the high-temperature melt flows down to the surface of the atomising disc spinning at very high speed. It is observed that there is a hydraulic jump of the melt flow prior to atomisation. In this paper, the dynamic model of the atomising disc as a spinning Kirchhoff plate with this hydraulic jump is established. The flowing melt is modelled as moving mass and weight force in the radial direction. Using a Galerkin method, it is found that the vibration properties of the atomising disc vary with the disc clamping ratio. The amplitude of the vibration is largely raised when the clamping ratio is smaller than the critical jump radius ratio. It is also found that the disc vibration is non-stationary before becoming steady and the amplitude decreases with increasing disc speed.

  15. Discs in misaligned binary systems

    CERN Document Server

    Rawiraswattana, Krisada; Goodwin, Simon P

    2016-01-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-...

  16. An Intelligent Regenerative Braking Strategy for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Zhibin Song

    2011-09-01

    Full Text Available Regenerative braking is an effective approach for electric vehicles (EVs to extend their driving range. A fuzzy-logic-based regenerative braking strategy (RBS integrated with series regenerative braking is developed in this paper to advance the level of energy-savings. From the viewpoint of securing car stability in braking operations, the braking force distribution between the front and rear wheels so as to accord with the ideal distribution curve are considered to prevent vehicles from experiencing wheel lock and slip phenomena during braking. Then, a fuzzy RBS using the driver’s braking force command, vehicle speed, battery SOC, battery temperature are designed to determine the distribution between friction braking force and regenerative braking force to improve the energy recuperation efficiency. The experimental results on an “LF620” prototype EV validated the feasibility and effectiveness of regenerative braking and showed that the proposed fuzzy RBS was endowed with good control performance. The maximum driving range of LF620 EV was improved by 25.7% compared with non-RBS conditions.

  17. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Train brake tests conducted using yard air. 232... Train brake tests conducted using yard air. (a) When a train air brake system is tested from a yard air... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The...

  18. Cervical Total Disc Arthroplasty

    OpenAIRE

    Basho, Rahul; Hood, Kenneth A.

    2012-01-01

    Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc...

  19. Accretion Discs in Blazars

    OpenAIRE

    Jolley, E. J. D.; Kuncic, Z.; Bicknell, G. V.; Wagner, S.(Max-Planck-Institut für Kernphysik, 69117, Heidelberg, Germany)

    2009-01-01

    The characteristic properties of blazars (rapid variability, strong polarization, high brightness) are widely attributed to a powerful relativistic jet oriented close to our line of sight. Despite the spectral energy distributions (SEDs) being strongly jet-dominated, a "big blue bump" has been recently detected in sources known as flat spectrum radio quasars (FSRQs). These new data provide a unique opportunity to observationally test coupled jet-disc accretion models in these extreme sources....

  20. Total disc replacement.

    Science.gov (United States)

    Vital, J-M; Boissière, L

    2014-02-01

    Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine.

  1. Power Modulation Investigation for High Temperature (175-200 degrees Celcius) Automotive Application

    Energy Technology Data Exchange (ETDEWEB)

    McCluskey, F. P.

    2007-04-30

    Hybrid electric vehicles were re-introduced in the late 1990s after a century dominated by purely internal combustion powered engines[1]. Automotive players, such as GM, Ford, DaimlerChrysler, Honda, and Toyota, together with major energy producers, such as BPAmoco, were the major force in the development of hybrid electric vehicles. Most notable was the development by Toyota of its Prius, which was launched in Japan in 1997 and worldwide in 2001. The shift to hybrids was driven by the fact that the sheer volume of vehicles on the road had begun to tax the ability of the environment to withstand the pollution of the internal combustion engine and the ability of the fossil fuel industry to produce a sufficient amount of refined gasoline. In addition, the number of vehicles was anticipated to rise exponentially with the increasing affluence of China and India. Over the last fifteen years, major advances have been made in all the technologies essential to hybrid vehicle success, including batteries, motors, power control and conditioning electronics, regenerative braking, and power sources, including fuel cells. Current hybrid electric vehicles are gasoline internal combustion--electric motor hybrids. These hybrid electric vehicles range from micro-hybrids, where a stop/start system cuts the engine while the vehicle is stopped, and mild hybrids where the stop/start system is supplemented by regenerative braking and power assist, to full hybrids where the combustion motor is optimized for electric power production, and there is full electric drive and full regenerative braking. PSA Peugeot Citroen estimates the increased energy efficiency will range from 3-6% for the micro-hybrids to 15-25% for the full hybrids.[2] Gasoline-electric hybrids are preferred in US because they permit long distance travel with low emissions and high gasoline mileage, while still using the existing refueling infrastructure. One of the most critical areas in which technology has been

  2. Apsidal precession, disc breaking and viscosity in warped discs

    CERN Document Server

    Nealon, Rebecca; Price, Daniel J; King, Andrew

    2015-01-01

    We demonstrate the importance of general relativistic apsidal precession in warped black hole accretion discs by comparing three - dimensional smoothed particle hydrodynamic simulations in which this effect is first neglected, and then included. If apsidal precession is neglected, we confirm the results of an earlier magnetohydrodynamic simulation which made this assumption, showing that at least in this case the $\\alpha$ viscosity model produces very similar results to those of simulations where angular momentum transport is due to the magnetorotational instability. Including apsidal precession significantly changes the predicted disc evolution. For moderately inclined discs thick enough that tilt is transported by bending waves, we find a disc tilt which is nonzero at the inner disc edge and oscillates with radius, consistent with published analytic results. For larger inclinations we find disc breaking.

  3. Mechanics of Actuated Disc Cutting

    Science.gov (United States)

    Dehkhoda, Sevda; Detournay, Emmanuel

    2017-02-01

    This paper investigates the mechanics of an actuated disc cutter with the objective of determining the average forces acting on the disc as a function of the parameters characterizing its motion. The specific problem considered is that of a disc cutter revolving off-centrically at constant angular velocity around a secondary axis rigidly attached to a cartridge, which is moving at constant velocity and undercutting rock at a constant depth. This model represents an idealization of a technology that has been implemented in a number of hard rock mechanical excavators with the goal of reducing the average thrust force to be provided by the excavation equipment. By assuming perfect conformance of the rock with the actuated disc as well as a prescribed motion of the disc (perfectly rigid machine), the evolution of the contact surface between the disc and the rock during one actuation of the disc can be computed. Coupled with simple cutter/rock interaction models that embody either a ductile or a brittle mode of fragmentation, these kinematical considerations lead to an estimate of the average force on the cartridge and of the partitioning of the energy imparted by the disc to the rock between the actuation mechanism of the disc and the translation of the cartridge on which the actuated disc is attached.

  4. Plasma Braking Due to External Magnetic Perturbations

    Science.gov (United States)

    Frassinetti, L.; Olofsson, Kejo; Brunsell, P. R.; Khan, M. W. M.; Drake, J. R.

    2010-11-01

    The RFP EXTRAP T2R is equipped with a comprehensive active feedback system (128 active saddle coils in the full-coverage array) and active control of both resonant and non-resonant MHD modes has been demonstrated. The feedback algorithms, based on modern control methodology such as reference mode tracking (both amplitude and phase), are a useful tool to improve the ``state of the art'' of the MHD mode control. But this tool can be used also to improve the understanding and the characterization of other phenomena such as the ELM mitigation with a resonant magnetic perturbation or the plasma viscosity. The present work studies plasma and mode braking due to static RMPs. Results show that a static RMP produces a global braking of the flow profile. The study of the effect of RMPs characterized by different helicities will also give information on the plasma viscosity profile. Experimental results are finally compared to theoretical models.

  5. INFLUENCE OF AUTOMOTIVE CLUSTERS IN REGIONAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Constantin BORDEI

    2014-11-01

    Full Text Available This paper proposes an overview of the evolution in the automotive sector in the process of regional development. The fundamental changes made by the component supplier sector improved the regional development and manufacturing process. Automotive industry is one of the modern sectors in many countries that benefits of a high technology impact and creates jobs that reduces unemployment across Europe. The auto industry changed cities, regions and countries into poles of development and it becomes more and more efficient. The high foreign direct investments from the automotive sector play an important role in regional development process. Continuous changes are being made in the economy, society, and company; in conclusion the automotive clusters will always be a subject of analysis.

  6. Nonlinear estimation and control of automotive drivetrains

    CERN Document Server

    Chen, Hong

    2014-01-01

    Nonlinear Estimation and Control of Automotive Drivetrains discusses the control problems involved in automotive drivetrains, particularly in hydraulic Automatic Transmission (AT), Dual Clutch Transmission (DCT) and Automated Manual Transmission (AMT). Challenging estimation and control problems, such as driveline torque estimation and gear shift control, are addressed by applying the latest nonlinear control theories, including constructive nonlinear control (Backstepping, Input-to-State Stable) and Model Predictive Control (MPC). The estimation and control performance is improved while the calibration effort is reduced significantly. The book presents many detailed examples of design processes and thus enables the readers to understand how to successfully combine purely theoretical methodologies with actual applications in vehicles. The book is intended for researchers, PhD students, control engineers and automotive engineers. Hong Chen is a professor at the State Key Laboratory of Automotive Simulation and...

  7. Fatal exit the automotive black box debate

    CERN Document Server

    Kowalick, Tom

    2005-01-01

    "Fatal Exit: The Automotive Black Box Debate cuts through thirty years of political wrangling and institutional biases to provide an argument for the Motor Vehicle Event Data Recorder (MVEDR). This automotive equivalent of an airplane's flight recorder or black box is intended to solve the mysteries of car crashes and improve the safety of our roads. The reader is taken inside the automotive industry and the government highway safety establishment to foster an understanding of the politics and the positions on all sides of this safety debate. The author takes an unbiased approach, chronologically presenting each argument and uncovering the agendas and mandates of each of the stakeholders." "This publication is essential reading for all consumers who need to have their voices heard on this critical issue, as well as for attorneys, public safety advocates, public policy administrators, engineers, automotive professionals, journalists, and insurance executives."--Jacket.

  8. 78 FR 36633 - National Automotive Sampling System

    Science.gov (United States)

    2013-06-18

    ... National Highway Traffic Safety Administration National Automotive Sampling System AGENCY: National Highway Traffic Safety Administration (NHTSA), Department of the Transportation (DOT). ACTION: Notice of public... regarding vehicle design and traffic safety. The NASS system currently has two components: the...

  9. 77 FR 37471 - National Automotive Sampling System

    Science.gov (United States)

    2012-06-21

    ... National Highway Traffic Safety Administration National Automotive Sampling System AGENCY: National Highway Traffic Safety Administration (NHTSA), Department of Transportation (DOT). ACTION: Notice and request for... make informed regulatory, program, and policy decisions regarding vehicle design and traffic...

  10. Sustainable automotive energy system in China

    CERN Document Server

    CAERC, Tsinghua University

    2014-01-01

    This book identifies and addresses key issues of automotive energy in China. It covers demography, economics, technology and policy, providing a broad perspective to aid in the planning of sustainable road transport in China.

  11. Transient Dynamical Analysis of Aircraft Wheel Brake Based on LS-DYNA%基于LS-DYNA的航空机轮刹车瞬态动力学分析∗

    Institute of Scientific and Technical Information of China (English)

    刘文胜; 项立东; 马运柱; 杨肃; 裴书杨

    2016-01-01

    In order to study the effect of the friction characteristics of the brake disc in the process of braking. In this paper, a three-dimensional solid model of an aircraft wheel brake disk is established by CATIA, then its finite element model is crea-ted by simplifying the geometry model; Transient dynamics analysis is carried out on the brake disk by using ANSYS / LS-DYNA(explicit dynamic analysis software). In the end, the node axial vibration curve and the distribution of stress of the brake during the process of brake are got.%为考虑刹车盘接触对之间的摩擦特性对刹车过程的影响,采用CATIA建立某型机轮刹车盘的三维实体模型,经简化后获得其有限元模型;利用ANSYS/LS-DYNA显示动力学分析软件,对刹车盘进行瞬态动力学分析,得到了动盘表面节点轴向振动曲线和刹车过程中刹车片的应力分布情况。

  12. A high performance pneumatic braking system for heavy vehicles

    Science.gov (United States)

    Miller, Jonathan I.; Cebon, David

    2010-12-01

    Current research into reducing actuator delays in pneumatic brake systems is opening the door for advanced anti-lock braking algorithms to be used on heavy goods vehicles. However, these algorithms require the knowledge of variables that are impractical to measure directly. This paper introduces a sliding mode braking force observer to support a sliding mode controller for air-braked heavy vehicles. The performance of the observer is examined through simulations and field testing of an articulated heavy vehicle. The observer operated robustly during single-wheel vehicle simulations, and provided reasonable estimates of surface friction from test data. The effect of brake gain errors on the controller and observer are illustrated, and a recursive least squares estimator is derived for the brake gain. The estimator converged within 0.3 s in simulations and vehicle trials.

  13. SELECTION METHOD FOR AUTOMOTIVE PARTS RECONDITIONING

    Directory of Open Access Journals (Sweden)

    Dan Florin NITOI

    2015-05-01

    Full Text Available Paper presents technological methods for metal deposition, costs calculation and clasification for the main process that helps in automotive technologies to repair or to increase pieces properties. Paper was constructed based on many technological experiments that starts from practicans and returns to them. The main aim is to help young engineers or practicians engineers to choose the proper reconditioning process with the best information in repairing pieces from automotive industry.

  14. Elastoplastic finite element analysis for wet multidisc brake during lasting braking

    Directory of Open Access Journals (Sweden)

    Ji Zhanling

    2015-01-01

    Full Text Available Addressed to serious heat degradation problem of the braking continuously performed in the drag brake application for a long time, finite element analysis for bidirectional thermal-structure coupling is adopted to investigate temperature and stress when material properties are temperature-dependent. Based on the constitutive relations of heat transfer and strain-stress, three-dimensional transient finite element equilibrium equations with many kinds of boundary conditions for bidirectional thermal-structure coupling were derived. And it was originally presented that start time, location, severity and evolution laws of plastic deformation were depicted using dimensionless stress distribution contour with the yield limit related to temperature. The change laws of plastic element number and contact area versus braking time were expressed by plasticity ratio and contact ratio curves, respectively. The laws revealed by the numerical calculation results are in accordance with the objective perception and reasoning.

  15. Dynamics of warped accretion discs

    OpenAIRE

    Tremaine, Scott; Davis, Shane W.

    2013-01-01

    Accretion discs are present around both stellar-mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei. A wide variety of circumstantial evidence implies that many of these discs are warped. The standard Bardeen--Petterson model attributes the shape of the warp to the competition between Lense--Thirring torque from the central black hole and viscous angular-momentum transport within the disc. We show that this description is incomplete, and that torques from...

  16. Hierarchical Control Strategy for the Cooperative Braking System of Electric Vehicle.

    Science.gov (United States)

    Peng, Jiankun; He, Hongwen; Liu, Wei; Guo, Hongqiang

    2015-01-01

    This paper provides a hierarchical control strategy for cooperative braking system of an electric vehicle with separated driven axles. Two layers are defined: the top layer is used to optimize the braking stability based on two sliding mode control strategies, namely, the interaxle control mode and signal-axle control strategies; the interaxle control strategy generates the ideal braking force distribution in general braking condition, and the single-axle control strategy can ensure braking safety in emergency braking condition; the bottom layer is used to maximize the regenerative braking energy recovery efficiency with a reallocated braking torque strategy; the reallocated braking torque strategy can recovery braking energy as much as possible in the premise of meeting battery charging power. The simulation results show that the proposed hierarchical control strategy is reasonable and can adapt to different typical road surfaces and load cases; the vehicle braking stability and safety can be guaranteed; furthermore, the regenerative braking energy recovery efficiency can be improved.

  17. Numbered nasal discs for waterfowl

    Science.gov (United States)

    Bartonek, J.C.; Dane, C.W.

    1964-01-01

    Numbered nasal discs were successfully used in studies requiring large numbers of individually marked waterfowl. The procedure for constructing these discs is outlined. Blue-winged teal (Anas discors) with 5/8-inch discs, and canvasback (Aythya valisineria) and redhead (A. americana) with 3/4-inch discs can be individually identified up to 50 and 80 yards, respectively, with a gunstock-mounted, 20-power spotting scope. The particular value of these markers is their durability, the number of combinations possible, and the apparent absence of behavioral or mortality influence among such species as the blue-winged teal.

  18. Development of Anti-lock Braking System (ABS) for Vehicles Braking

    Science.gov (United States)

    Minh, Vu Trieu; Oamen, Godwin; Vassiljeva, Kristina; Teder, Leo

    2016-11-01

    This paper develops a real laboratory of anti-lock braking system (ABS) for vehicle and conducts real experiments to verify the ability of this ABS to prevent the vehicle wheel from being locked while braking. Two controllers of PID and fuzzy logic are tested for analysis and comparison. This ABS laboratory is designed for bachelor and master students to simulate and analyze performances of ABS with different control techniques on various roads and load conditions. This paper provides educational theories and practices on the design of control for system dynamics.

  19. Impact Damage Evaluation Method of Friction Disc Based on High-Speed Photography and Tooth-Root Stress Coupling

    Science.gov (United States)

    Yin, L.; Shao, Y. M.; Liu, J.; Zheng, H. L.

    2015-07-01

    The stability of friction disc could be seriously affected by the tooth surface damage due to poor working conditions of the wet multi-disc brake in heavy trucks. There are few current works focused on the damage of the friction disc caused by torsion-vibration impacts. Hence, it is necessary to investigate its damage mechanisms and evaluation methods. In this paper, a damage mechanism description and evaluation method of a friction disc based on the high-speed photography and tooth-root stress coupling is proposed. According to the HighSpeed Photography, the collision process between the friction disc and hub is recorded, which can be used to determine the contact position and deformation. Combined with the strain-stress data obtained by the strain gauge at the place of the tooth-root, the impact force and property are studied. In order to obtain the evaluation method, the damage surface morphology data of the friction disc extracted by 3D Super Depth Digital Microscope (VH-Z100R) is compared with the impact force and property. The quantitative relationships between the amount of deformation and collision number are obtained using a fitting analysis method. The experimental results show that the damage of the friction disc can be evaluated by the proposed impact damage evaluation method based on the high-speed photography and tooth-root stress coupling.

  20. An Investigation into the Behavior of Disc Blake Wear

    Directory of Open Access Journals (Sweden)

    Muneer A. H.Jassim

    2007-01-01

    Full Text Available A real method of predication brake pad wear ,could lead to substantiol economies of time and money. This paper describes how such a procedure has been used and gives the results to establish is reliability by comparing the predicted wear with that which actually occurs in an existing service. The experimental work was carried out on three different commercial samples ,tested under different operation conditions (speed,load,time...etcusing a test ring especially modified for this purpose. Abrasive wear is mainly studied , since it is the type of wear that takes place in such arrangements. Samples wear tested in presences of sand or mud between the mating surfaces under different operational conditions of speed, load and braking time .Mechanical properties of the pad material samples (hardness, young,s modulus and collapse load under pure bending condition wear established . The thermal conductivity and surface roughness of the pad material wear also found in order to enable comparison between the surface condition before and after testing. Sliding velocity had a small effect on the wear rate but it had great effect on friction coefficient. Wear rate was affected mainly by the surface temperature which causing a reduction friction coefficient and increasing the wear rate. Surface roughness had almost no effect on the wear rate since it was proved experimentally ,that the surface becomes softer during operation .mechanical properties of the pad material had fluctuating effect on wear rate. The existence of solid particles between pad and disc increasing wear rate and friction coefficient while the mud caused a reduction in wear rate of the pad surface since it acts as a lubricant absorbing the surface heat generated during sliding the area of contact between pad and disc. wear rate obtained experimentally agreed fairly well that found from empirically obtained equations.

  1. Research on Modeling and Control of Regenerative Braking for Brushless DC Machines Driven Electric Vehicles

    OpenAIRE

    Jian-ping Wen; Chuan-wei Zhang

    2015-01-01

    In order to improve energy utilization rate of battery-powered electric vehicle (EV) using brushless DC machine (BLDCM), the model of braking current generated by regenerative braking and control method are discussed. On the basis of the equivalent circuit of BLDCM during the generative braking period, the mathematic model of braking current is established. By using an extended state observer (ESO) to observe actual braking current and the unknown disturbances of regenerative braking system, ...

  2. 75 FR 34170 - Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium Automotive Exteriors, LLC...

    Science.gov (United States)

    2010-06-16

    ... Employment and Training Administration Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium... Assistance on March 18, 2010, applicable to workers of Plastic Omnium Automotive Exteriors, LLC, Anderson... have occurred involving workers in support of the Anderson, South Carolina location of Plastic...

  3. Relativistic Disc lines

    CERN Document Server

    Fabian, A C; Parker, M L

    2014-01-01

    Broad emission lines, particularly broad iron-K lines, are now commonly seen in the X-ray spectra of luminous AGN and Galactic black hole binaries. Sensitive NuSTAR spectra over the energy range of 3-78 keV and high frequency reverberation spectra now confirm that these are relativistic disc lines produced by coronal irradiation of the innermost accretion flow around rapidly spinning black holes. General relativistic effects are essential in explaining the observations. Recent results are briefly reviewed here.

  4. Study of LED modulation effect on the photometric quantities and beam homogeneity of automotive lighting

    Science.gov (United States)

    Koudelka, Petr; Hanulak, Patrik; Jaros, Jakub; Papes, Martin; Latal, Jan; Siska, Petr; Vasinek, Vladimir

    2015-07-01

    This paper discusses the implementation of a light emitting diode based visible light communication system for optical vehicle-to-vehicle (V2V) communications in road safety applications. The widespread use of LEDs as light sources has reached into automotive fields. For example, LEDs are used for taillights, daytime running lights, brake lights, headlights, and traffic signals. Future in the optical vehicle-to-vehicle (V2V) communications will be based on an optical wireless communication technology that using LED transmitter and a camera receiver (OCI; optical communication image sensor). Utilization of optical V2V communication systems in automotive industry naturally brings a lot of problems. Among them belongs necessity of circuit implementation into the current concepts of electronic LED lights control that allows LED modulation. These circuits are quite complicated especially in case of luxury cars. Other problem is correct design of modulation circuits so that final vehicle lightning using optical vehicle-to-vehicle (V2V) communication meets standard requirements on Photometric Quantities and Beam Homogeneity. Authors of this article performed research on optical vehicle-to-vehicle (V2V) communication possibilities of headlight (Jaguar) and taillight (Skoda) in terms of modulation circuits (M-PSK, M-QAM) implementation into the lamp concepts and final fulfilment of mandatory standards on Photometric Quantities and Beam Homogeneity.

  5. 盘式制动器的热分析%Thermal analysis of disc brake system

    Institute of Scientific and Technical Information of China (English)

    韩建荣; 翁建生

    2008-01-01

    针对盘式制动器,提出了利用热源法计算出制动盘的温度场,并与实验结果进行了对比,结果表明该方法是可行的,并结合热弹性理论计算出制动盘的热变形,最后分析了制动盘的结构参数对热变形的影响,包括散热壁面的长度、通风式与实心式,并进行了曲线拟合与对比分析,为进一步分析制动抖动及其预测相应的振动量提供指导.

  6. Accretion discs trapped near corotation

    NARCIS (Netherlands)

    D'Angelo, C.R.; Spruit, H.C.

    2012-01-01

    We show that discs accreting on to the magnetosphere of a rotating star can end up in a trapped state, in which the inner edge of the disc stays near the corotation radius, even at low and varying accretion rates. The accretion in these trapped states can be steady or cyclic; we explore these states

  7. Analysis of Transient Temperature and Thermal Stress Distribution on the High-speed Strain Brake Disk by Simulation%高速列车制动盘瞬态温度和热应力分布仿真分析

    Institute of Scientific and Technical Information of China (English)

    周素霞; 杨月; 谢基龙

    2011-01-01

    制动盘的热疲劳损伤是当前列车安全制动的主要威胁.制动过程中的瞬态温度和热应力分布是热疲劳损伤研究的基础.通过建立制动盘无内热源的三维温度场分布的数学计算模型,采用热弹塑性有限元法,利用摩擦功率法计算温度场载荷,仿真不同制动工况下制动盘摩擦热负荷产生的温度场以及热应力分布.主要计算一次常用制动、一次紧急制动、三次紧急制动和一次坡道制动这4种制动工况.通过仿真分析发现,不同工况下制动盘面的温度变化有着相似的规律.制动开始阶段,随着强热流的不断输入,盘面在很短时间内迅速升温,很快达到峰值点.随后,盘体逐渐通过辐射和对流的方式散热,温度缓慢下降.相对紧急制动和常用制动的升温过程,坡道制动的升温显得缓慢一些.研究不同工况下制动盘温度和热应力的变化和分布规律,为高速列车复合材料制动盘的热疲劳性能评价提供依据.%At present the thermal fatigue damage of brake disks is the main threaten of train brake safety. The transient temperature and thermal stress distribution on the disk during the braking are the basis for research on the thermal fatigue damage. In order to simulate the temperature field and thermal stress distribution from the thermal load caused by the friction during braking under different conditions, the math model of 3D temperature field without inside thermal source of the brake disc is built and the thermal elastic-plastic finite element method is used. At the same time, the temperature field load is calculated with fiction power method and the brake cases are one time usual brake, one time emergent brake, three times emergent brake and one time ramp brake respectively. It is shown that the temperature change rules on the brake disk surfaces are similar under different cases. At the beginning of brake the temperature rises fast with the strong thermal flow

  8. Research of blended braking characteristics of super-big electric wheels of mining dump truck%特大型电动轮矿用自卸车联合制动特性研究

    Institute of Scientific and Technical Information of China (English)

    罗春雷; 钟锡继; 吴伟传

    2012-01-01

    In order to obtain the blended braking characteristics of super-big electric wheels of mining dump truck on different downhill slope, and analyze the power distribution between grid resistance electric dynamic brake and hydraulic wet multi-disc brake, the dynamic model of blended braking system was established by using a certain type of 520 tons gross vehicle weight dump truck as research object. Results show that with the initial velocity of 30 km/h, emergency braking distance is less than 21 m on different slopes below 10% ; the average specific brake force nearly remain unchanged on different slope, and the maximum value is about 0. 35; for rear specific brake force is bigger than that of front, the possibility of sideslip and deviation is bigger than that of out of steering control; the specific brake force difference between rear and front can be reduced by moving the center of gravity to the rear axle, while the average specific brake force remain unchanged, so the ground adhesion can used effectively; the brake power ratio between grid resistance and wet multi-disc brake is about 2- 3. These results shows that the blended braking system can reduce the brakes load effectively, increase braking performance, and extend the service life of the main brakes.%为了研究特大型电动轮矿用自卸车下坡联合制动时的制动特性,分析联合制动时电阻栅能耗制动及液压多片湿盘式制动器制动功率的分配,以湘电重装满载整车重量达520t的自卸车为研究对象,建立了自卸车电阻栅能耗制动及液压多片湿盘式制动器联合制动系统动力学模型,利用Mtlab/simulink对该自卸车在不同下坡坡道上的紧急联合制动进行了数值分析计算,获得制动特性曲线.结果表明:初速度为30 km/h时,在不高于10%的坡度下紧急制动距离不超过21 m;平均比制动力在不同坡道基本保持不变,最高值为0.35左右;后轮比制动力大于前轮比制动力,侧滑、跑

  9. Green competitiveness research on Chinese automotive enterprises

    Directory of Open Access Journals (Sweden)

    Yuanhui Li

    2014-05-01

    Full Text Available Purpose: More and more executives of automobileindustry in China start to recognize the concept of green competitiveness recently. However, relatively less research attention has been devoted to the consideration of measurement. This paper aims to find empirical approach to quantify green competitiveness for automotive enterprises. The connotation of green competitiveness is explored and one suite of evaluation index system has been proposed with four dimensions including environmental, resource, capability and knowledge.Design/methodology/approach: By introducing the factor analysis method, green competitiveness has been measured through an empirical analysis of 24 automotive enterprises within China.Findings: The results indicate that those elements, such as enterprise resource possession and utilization; environment, responsibility and knowledge; profitability; management efficiency, have significant effect on the green competitiveness for automotive enterprises. The further analysis also unveils the advantages and disadvantages of green competitiveness for each company and the direction for improvement.Research limitations/implications: Guide regulators and managers of automobile industry to take some measures to enhance their green competitive advantage.Practical implications: Provide practical methods to measure green competitiveness for automotive enterprises.Originality/value: This paper proposes an evaluation index system of green competitiveness for automotive enterprises. The suggestions of our research will be beneficial to enterprise executives and industry regulators.

  10. Intraoral micro-identification discs.

    Science.gov (United States)

    Hansen, R W

    1991-12-01

    Intraoral micro-identification discs have recently been utilized to provide a more permanent method of personal identification. A wafer of plastic or metal with a surface area of 2.5 to 5 mm2 and carrying identifying numbers and/or letters (indicia) is bonded to the buccal enamel surface of the posterior teeth. Personal identification can occur after the I.D. disc is identified and the indicia is read. Reading of photoreduced indicia requires the aid of a microscope subsequent to the removal of the microdisc. In situ reading of disc indicia is possible using low power handheld magnifiers if the size of the indicia approximates 0.3 mm. Computerization is an integral part of non-custom alpha/numeric type designs, but a custom disc carries a name, address, and other specific information unique to the manufacturer. The use of a computer improves access to the database and it decreases the amount of data placed on the disc. Microdisc bases may be fabricated using a mylar type plastic or they may be manufactured from a stainless steel blank. Plastic discs are constructed with an internal sandwich containing the photo-reduced indicia. Metal discs are marked with a photochemical etch or engraved with a computer driven YAG laser. Attachment of the disc to the enamel surface is accomplished by conventional etching and bonding techniques and are typically bonded to the buccal surface of the maxillary first permanent molar or the second primary molar. Clear composite bonding material covers the disc so that salivary contamination does not result in degradation of the indicia. Orthodontic style discs with a mesh back carry laser written information that may be cemented with conventional orthodontic bonding cement. Standardization of the indicia and overall design is considered to be an important aspect of patient and professional acceptance.

  11. THE THEORETICAL MODEL FOR PREDICTING CIRCULATION VELOCITY OF HYDRAULIC BRAKE

    Institute of Scientific and Technical Information of China (English)

    刘英林; 侯春生

    1997-01-01

    By rational hypothesis of fluid flow pattern, applied the law of conservation of energy and integrated the laboratory test results, finished the prediction by the theoretical model of circulation velocity of hydraulic brake which is important parameter. Thus provide the theoritical basis for hydraulic brake of belt conveyor whose research has just been started.

  12. Ileal brake activation: Macronutrient-specific effects on eating behavior?

    NARCIS (Netherlands)

    Avesaat, M. van; Troost, F.J.; Ripken, D.; Hendriks, H.F.; Aam, M.

    2015-01-01

    BACKGROUND: Activation of the ileal brake, by infusing lipid directly into the distal part of the small intestine, alters gastrointestinal (GI) motility and inhibits food intake. The ileal brake effect on eating behavior of the other macronutrients is currently unknown. OBJECTIVE: The objective of t

  13. Characterisation of motorcyclist's upper body motion during braking manoeuvre

    NARCIS (Netherlands)

    Ioannis, S.; Kavadarli, G.; Fraga, F.; Rooij, L. van; Schuller, E.; Peldschus, S.

    2010-01-01

    Motorcycle braking experiments with volunteers were performed in lab, to study the body posture and reactions of the motorcyclists during braking with the aim of providing input for human modelling. Human motion capture methods were employed for the kinematics and the recorded data was further analy

  14. Development of a multi-pole magnetorheological brake

    Science.gov (United States)

    Shiao, Yaojung; Nguyen, Quang-Anh

    2013-06-01

    This paper presents a new approach in the design and optimization of a novel multi-pole magnetorheological (MR) brake that employs magnetic flux more effectively on the surface of the rotor. MR brakes with conventional single ring-type electromagnetic poles have reached the limits of torque enhancement. One major reason is the limitation of the magnetic field strength within the active area of the MR fluid due to the geometric constraints of the coil. The multi-pole MR brake design features multiple electromagnetic poles surrounded by several coils. As a result, the active chaining areas for the MR fluid are greatly increased, and significant brake torque improvement is achieved. The coil structure, as a part of the stator, becomes flexible and customizable in terms of space usage for the winding and bobbin design. In addition, this brake offers extra options in its dimensions for torque enhancement because either the radial or the axial dimensions of the rotor can be increased. Magnetic circuit analysis was conducted to analyze the effects of the design parameters on the field torque. After that, simulations were done to find the optimal design under all major geometric constraints with a given power supply. The results show that the multi-pole MR brake provides a considerable braking torque increase while maintaining a compact and solid design. This is confirmation of its feasibility in actual braking applications.

  15. 49 CFR 393.48 - Brakes to be operative.

    Science.gov (United States)

    2010-10-01

    ...) The steering axle of a three-axle dolly which is steered by a co-driver; (5) Loaded house moving... times be capable of operating. (b) Devices to reduce or remove front-wheel braking effort. A commercial motor vehicle may be equipped with a device to reduce the front wheel braking effort (or in the case...

  16. Ileal brake activation: macronutrient-specific effects on eating behavior?

    NARCIS (Netherlands)

    Avesaat, van M.; Troost, F.J.; Ripken, D.; Hendriks, H.F.; Masclee, A.A.M.

    2015-01-01

    Background:Activation of the ileal brake, by infusing lipid directly into the distal part of the small intestine, alters gastrointestinal (GI) motility and inhibits food intake. The ileal brake effect on eating behavior of the other macronutrients is currently unknown.Objective:The objective of this

  17. Abnormal Sound Generated by the Braking of Steel Rim of Moped Wheel%踏板车钢制轮圈制动异响问题探析

    Institute of Scientific and Technical Information of China (English)

    何宇; 魏赫; 刘莉

    2012-01-01

    Home-made mopeds are usually fitted with steel rims and drum discs. That easily generates harsh abnormal sound due to the mismatch of materials of brake shoes and brake hubs. The materials for brake hub has direct influence on braking performance, such as the heat conduction rate, and vibration reduction etc. The best solution for this problem is to optimize the structure of wheel and use proper materials.%国内小踏板车常配置钢制辐板轮圈并采用鼓式制动,在骑乘,特别是制功时,常会伴有刺耳的异响声。产生异响的主要原因是轮圈制动毂本身材质与制动蹄块材料匹配不好,制动毂材质的选取直接影响制动时的热导率、消振性能,引起不良噪声。要想解决该问题,主要取决于轮圈的结构形式、材料选用等,但具体问题还要具体分析,针对性地解决。

  18. Evolution of protoplanetary discs with magnetically driven disc winds

    Science.gov (United States)

    Suzuki, Takeru K.; Ogihara, Masahiro; Morbidelli, Alessandro; Crida, Aurélien; Guillot, Tristan

    2016-12-01

    Aims: We investigate the evolution of protoplanetary discs (PPDs) with magnetically driven disc winds and viscous heating. Methods: We considered an initially massive disc with 0.1 M⊙ to track the evolution from the early stage of PPDs. We solved the time evolution of surface density and temperature by taking into account viscous heating and the loss of mass and angular momentum by the disc winds within the framework of a standard α model for accretion discs. Our model parameters, turbulent viscosity, disc wind mass-loss, and disc wind torque, which were adopted from local magnetohydrodynamical simulations and constrained by the global energetics of the gravitational accretion, largely depends on the physical condition of PPDs, particularly on the evolution of the vertical magnetic flux in weakly ionized PPDs. Results: Although there are still uncertainties concerning the evolution of the vertical magnetic flux that remains, the surface densities show a large variety, depending on the combination of these three parameters, some of which are very different from the surface density expected from the standard accretion. When a PPD is in a wind-driven accretion state with the preserved vertical magnetic field, the radial dependence of the surface density can be positive in the inner region migration of protoplanets. Conclusions: The variety of our calculated PPDs should yield a wide variety of exoplanet systems.

  19. FE Analysis of Drum Brake based on Multi-point Constraints Method%基于多点约束法的鼓式制动器有限元分析

    Institute of Scientific and Technical Information of China (English)

    吕彭民; 赵毛毛; 吴阿明

    2013-01-01

    为研究径向浮动蹄式制动器的性能特点,利用接触与多点约束相结合的方法,建立了结构有限元模型.经对比发现,该模型较传统模型能更准确的反映摩擦片的受力状态,且制动力矩仿真结果与试验数据有较好的一致性.利用该模型对制动器制动性能和摩擦片应力分布情况进行的仿真计算结果表明,径向浮动蹄式制动器有利于改善车辆制动跑偏现象和领蹄的受力状况,提高车辆的行车安全性和领蹄摩擦片的耐磨性:从蹄的受力均匀性有待进一步提高.%In order to study the performance characteristic of radial floating drum brake,a finite element model was created with the method based the multi-point constraints (MPC)method.This model was proved to be more accurate to reflectload bearing status of friction disc than that created by traditional method,and the result of braking torque simulation is more consistent with test data.Braking performance and stress distribution of friction disc of the brake was simulated by this model and the result showed that the radial floating drum brake can help improving the brake deviation and the force status of leading shoe,enhancing the running safety and wearability of the leading shoe.But uniformity of the forced status of trailing shoes need to be improved.

  20. Parity space-based fault diagnosis of CCBII braking system

    Institute of Scientific and Technical Information of China (English)

    黄志武; 杨迎泽; 王晶; 李赟

    2013-01-01

    Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faults. A parity space-based method was proposed for fault diagnosis of CCBII braking systems. Firstly, the mathematical models were established according to three function modules of CCBII braking systems where the air fluid theory was utilized. Then, parity vector and threshold function were designed for each output of the system so as to identify more system faults. Fault character matrix was built based on the causal relationship between the output and the fault according to the system function and internal structure. Finally, fault detection and isolation can be realized by the comparison of the observed system output and the fault character matrix. Simulation results show that the proposed method is entirely feasible and effective.

  1. Development of Asbestos - Free Brake Pad Using Bagasse

    Directory of Open Access Journals (Sweden)

    V. S. Aigbodion

    2010-03-01

    Full Text Available Development of asbestos-free brake pad using bagasse was investigated with a view to replace the use of asbestos whose dust is carcinogenic. The bagasse were sieve into sieve grades of 100, 150, 250, 350 and 710µm. the sieve bagasse was used in production of brake pad in ratio of 70%bagasse-30%resin using compression moulding. The properties examined are microstructure analysis, hardness, compressive strength, density, flame resistance, water and oil absorption. The microstructure reveals uniform distribution of resin in the bagasse. The results obtained showed that the finer the sieve size the better the properties. The results obtained in this work were compared with that of commercial brake pad (asbestos based and optimum formulation laboratory brake pad Palm Kernel Shell based (PKS, the results are in close agreement. Hence bagasse can be used in production of asbestos-free brake pad.

  2. Design optimization of a magnetorheological brake in powered knee orthosis

    Science.gov (United States)

    Ma, Hao; Liao, Wei-Hsin

    2015-04-01

    Magneto-rheological (MR) fluids have been utilized in devices like orthoses and prostheses to generate controllable braking torque. In this paper, a flat shape rotary MR brake is designed for powered knee orthosis to provide adjustable resistance. Multiple disk structure with interior inner coil is adopted in the MR brake configuration. In order to increase the maximal magnetic flux, a novel internal structure design with smooth transition surface is proposed. Based on this design, a parameterized model of the MR brake is built for geometrical optimization. Multiple factors are considered in the optimization objective: braking torque, weight, and, particularly, average power consumption. The optimization is then performed with Finite Element Analysis (FEA), and the optimal design is obtained among the Pareto-optimal set considering the trade-offs in design objectives.

  3. Coevolution of Binaries and Gaseous Discs

    CERN Document Server

    Fleming, David P

    2016-01-01

    The recent discoveries of circumbinary planets by $\\it Kepler$ raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc, and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc that drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for $10^4$ binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentri...

  4. Branding through trade shows in the automotive industry

    OpenAIRE

    Narui, Jahan

    2013-01-01

    The automotive industry is a major global industry with a great history of exhibitions. As trade shows are getting more attention within studies, the same is not the case for automotive trade shows. Noteworthy, automotive trade shows emphasize non-selling roles such as image-building. This paper seeks to investigate image-building purposes of exhibiting automotive companies using integrated marketing communications (IMC). Data has been gathered from four participating companies in the Geneva ...

  5. My father’s automotive dream

    Institute of Scientific and Technical Information of China (English)

    Rain Chen

    2005-01-01

    <正>Memories of Changchun Changchun literally means ’Long Spring’. The city is located in northeast China’s Jilin province, which literally means ’Lucky Forest’. Since my father is an old worker of Changchun’s Yi Qi(the abbreviation of Changchun First Automotive Factory) plant - China’s earliest automotive plant, I have spent 60 years in the city, graduating from the well-established Jilin University and currently working for a periodical association. A friend from Beijing encouraged me to write my family’s history, and since my family’s story is really a story about the good name of Changchun, an automotive city and a college town, I couldn’t refuse.

  6. Advanced casting technologies for lightweight automotive applications

    Directory of Open Access Journals (Sweden)

    Alan A. Luo

    2010-11-01

    Full Text Available This paper provides an overview of alloy and process developments in aluminum and magnesium castings for lightweight automotive applications. Wear-resistant aluminum alloys, creep-resistant and high strength/ductility magnesium alloys have been developed for automotive applications. On the process front, vacuum-assisted die casting and high vacuum die casting technologies have been developed for high-integrity body and chassis applications. Thin-wall and hollow casting components are being produced by low-pressure die casting processes for structural applications. Overcasting technology is gaining traction and has enabled mixed material designs for automotive sub-systems such as engine cradles and instrument panel beams. Simulation tools developed to predict the interfacial interactions of the dissimilar components and the structural integrity of the overcast systems are being validated in the casting trials.

  7. Optimization and optimal control in automotive systems

    CERN Document Server

    Kolmanovsky, Ilya; Steinbuch, Maarten; Re, Luigi

    2014-01-01

    This book demonstrates the use of the optimization techniques that are becoming essential to meet the increasing stringency and variety of requirements for automotive systems. It shows the reader how to move away from earlier  approaches, based on some degree of heuristics, to the use of  more and more common systematic methods. Even systematic methods can be developed and applied in a large number of forms so the text collects contributions from across the theory, methods and real-world automotive applications of optimization. Greater fuel economy, significant reductions in permissible emissions, new drivability requirements and the generally increasing complexity of automotive systems are among the criteria that the contributing authors set themselves to meet. In many cases multiple and often conflicting requirements give rise to multi-objective constrained optimization problems which are also considered. Some of these problems fall into the domain of the traditional multi-disciplinary optimization applie...

  8. Automotive Radar Sensors in Silicon Technologies

    CERN Document Server

    Jain, Vipul

    2013-01-01

    This book presents architectures and design techniques for mm-wave automotive radar transceivers. Several fully-integrated transceivers and receivers operating at 22-29 GHz and 77-81 GHz are demonstrated in both CMOS and SiGe BiCMOS technologies. Excellent performance is achieved indicating the suitability of silicon technologies for automotive radar sensors.  This book bridges an existing gap between information available on dependable system/architecture design and circuit design.  It provides the background of the field and detailed description of recent research and development of silicon-based radar sensors.  System-level requirements and circuit topologies for radar transceivers are described in detail. Holistic approaches towards designing radar sensors are validated with several examples of highly-integrated radar ICs in silicon technologies. Circuit techniques to design millimeter-wave circuits in silicon technologies are discussed in depth.  Describes concepts and fundamentals of automotive rada...

  9. Best Practices in School-to-Careers: The Automotive Industry.

    Science.gov (United States)

    National Employer Leadership Council, Washington, DC.

    This document highlights the school-to-careers (STC) partnerships connecting workplace experiences to classroom learning to prepare students for successful employment in the automotive industry. First, the current state of the automotive industry is reviewed and the role of STC in addressing automotive service needs is explained. Next, the…

  10. 25 CFR 117.10 - Purchase of automotive equipment.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Purchase of automotive equipment. 117.10 Section 117.10... COMPETENCY § 117.10 Purchase of automotive equipment. The superintendent may disburse from the surplus funds of an adult Indian not to exceed $2,000 for the purchase of automotive equipment when the...

  11. Can Distance Learning Be Used to Teach Automotive Management Skills?

    Science.gov (United States)

    Noto, Teresa L.

    2011-01-01

    Today's automotive college students will shape the future of the automobile industry. The success of college-level automotive programs has long been dependent on the students' ability to participate in hands-on classroom based interactions. In this article, distance learning and how it can be used to teach automotive management skills, as well as…

  12. Design and Analysis of Electro-mechanical Hybrid Anti-lock Braking System for Hybrid Electric Vehicle Utilizing Motor Regenerative Braking

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jianlong; YIN Chengliang; ZHANG Jianwu

    2009-01-01

    Braking on low adhesion-coefficient roads, hybrid electric vehicle's motor regenerative torque is switched off to safeguard the normal anti-lock braking system (ABS) function. When the ABS control is terminated, the motor regenerative braking is readmitted.Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure. The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.

  13. PROTOBINARY EVOLUTION DRIVEN BY MAGNETIC BRAKING

    Science.gov (United States)

    Zhao, Bo; Li, Z.; Kratter, K. M.

    2014-01-01

    The majority of stars are in multiple systems, especially binaries. Such objects form in dense cores of molecular clouds that are observed to be strongly magnetized. Most previous studies of binary formation have either ignored magnetic fields or focused on the initial core fragmentation into binary seeds. Here I focus on the effects of the magnetic field on the orbital evolution of the protobinary during the main accretion phase, after a pair of stellar seeds have formed. By simulating a 'seed' binary system with the sink particle treatment, we show that magnetic field plays a crucial role in removing the gas angular momentum and shrinking the binary separation. Through magnetic braking, strong magnetic field is very effective in suppressing the formation of circumstellar disks and circumbinary disk along with its spiral arm structures. The magnetic field can also be responsible for the population of the low mass-ratio binaries in the observed distribution. The magnetically-braked material will have equal chance of being accreted onto either binary seed, instead of the preferential accretion onto the secondary when magnetic field is absent. Furthermore, large field mis-alignment helps to produce rotationally-supported circumbinary disks even for relatively strong magnetic fields, by weakening the magnetically-dominated structure close to the binary. Hence to explain the observed properties of binaries, the magnetic effects deserve more careful considerations in the larger context of binary formation in future studies.

  14. Simulation study of the plasma brake effect

    CERN Document Server

    Janhunen, Pekka

    2014-01-01

    The plasma brake is a thin negatively biased tether which has been proposed as an efficient concept for deorbiting satellites and debris objects from low Earth orbit. We simulate the interaction with the ionospheric plasma ram flow with the plasma brake tether by a high performance electrostatic particle in cell code to evaluate the thrust. The tether is assumed to be perpendicular to the flow. We perform runs for different tether voltage, magnetic field orientation and plasma ion mass. We show that a simple analytical thrust formula reproduces most of the simulation results well. The interaction with the tether and the plasma flow is laminar when the magnetic field is perpendicular to the tether and the flow. If the magnetic field is parallel to the tether, the behaviour is unstable and thrust is reduced by a modest factor. The case when the magnetic field is aligned with the flow can also be unstable, but does not result in notable thrust reduction. We also fix an error in an earlier reference. According to...

  15. Nanotechnology impact on the automotive industry.

    Science.gov (United States)

    Wong, Kaufui V; Paddon, Patrick A

    2014-01-01

    Nanotechnology has been implemented widely in the automotive industry. This technology is particularly useful in coatings, fabrics, structural materials, fluids, lubricants, tires, and preliminary applications in smart glass/windows and video display systems. A special sub-class of improved materials, alternative energy, has also seen a boost from advances in nanotechnology, and continues to be an active research area. A correlation exists in the automotive industry between the areas with increased nanotechnology incorporation and those with increased profit margins via improvements and customer demands.

  16. Accretion discs trapped near corotation

    OpenAIRE

    D'Angelo, C.R.; Spruit, H.C.

    2012-01-01

    We show that discs accreting on to the magnetosphere of a rotating star can end up in a trapped state, in which the inner edge of the disc stays near the corotation radius, even at low and varying accretion rates. The accretion in these trapped states can be steady or cyclic; we explore these states over a wide range of parameter space. We find two distinct regions of instability: one related to the buildup and release of mass in the disc outside corotation, and the other to mass storage with...

  17. 49 CFR 232.211 - Class III brake tests-trainline continuity inspection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Class III brake tests-trainline continuity... § 232.211 Class III brake tests-trainline continuity inspection. (a) A Class III brake test shall be... configuration of the train has changed in certain ways. In particular, a Class III brake test shall be...

  18. 49 CFR 232.103 - General requirements for all train brake systems.

    Science.gov (United States)

    2010-10-01

    ... pneumatic technology, the integrity of the train line shall be monitored by the brake control system. (c) A... straight air brake 30-50 (7) Self-lapping portion for electro-pneumatic brake (minimum full application... 49 Transportation 4 2010-10-01 2010-10-01 false General requirements for all train brake...

  19. Research on Modeling and Control of Regenerative Braking for Brushless DC Machines Driven Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Jian-ping Wen

    2015-01-01

    Full Text Available In order to improve energy utilization rate of battery-powered electric vehicle (EV using brushless DC machine (BLDCM, the model of braking current generated by regenerative braking and control method are discussed. On the basis of the equivalent circuit of BLDCM during the generative braking period, the mathematic model of braking current is established. By using an extended state observer (ESO to observe actual braking current and the unknown disturbances of regenerative braking system, the autodisturbances rejection controller (ADRC for controlling the braking current is developed. Experimental results show that the proposed method gives better recovery efficiency and is robust to disturbances.

  20. Modelling Neutral Hydrogen Discs of Spiral Galaxies

    Institute of Scientific and Technical Information of China (English)

    林伟鹏; 洪碧海

    2002-01-01

    We present an analytical model of a neutral hydrogen disc in a spiral galaxy. The gas disc of the spiral galaxy isassumed to have an exponential surface density profile and to be ionized by the cosmic ultraviolet background.To compare with observations, we consider the disc position angle and inclination angle for a line of sight goingthrough the galaxy disc. The HI column densities depend on the strength of ionizing field and disc position andinclination. The model was applied to NGC 3198 and the results were compared with observational data. TheHI disc profile at large disc radii can be tested by further HI observations using radio telescopes with a largeraperture than the present facilities. This HI disc model can be used to predict quasar absorption line systems bygalaxy discs if quasar lines of sight go through the discs.

  1. Debris disc formation induced by planetary growth

    CERN Document Server

    Kobayashi, Hiroshi

    2014-01-01

    Several hundred stars older than 10 million years have been observed to have infrared excesses. These observations are explained by dust grains formed by the collisional fragmentation of hidden planetesimals. Such dusty planetesimal discs are known as debris discs. In a dynamically cold planetesimal disc, collisional coagulation of planetesimals produces planetary embryos which then stir the surrounding leftover planetesimals. Thus, the collisional fragmentation of planetesimals that results from planet formation forms a debris disc. We aim to determine the properties of the underlying planetesimals in debris discs by numerically modelling the coagulation and fragmentation of planetesimal populations. The brightness and temporal evolution of debris discs depend on the radial distribution of planetesimal discs, the location of their inner and outer edges, their total mass, and the size of planetesimals in the disc. We find that a radially narrow planetesimal disc is most likely to result in a debris disc that ...

  2. Research progress of aluminum alloy automotive sheet and application technology

    Institute of Scientific and Technical Information of China (English)

    Ma Mingtu; You Jianghai; Lu Hongzhou; Wang Zhiwen

    2012-01-01

    Pretrcatment technology is deeply discussed to explain its importance in guaranteeing properties and form- ability of aluminum alloy automotive sheet. Some typical applications of aluminum alloy automotive sheet to automotive industry are listed. Based on the author's knowledge and recognition and research progress presently, the important re- search contents about aluminum alloy automotive sheet are emphasized. Reducing cost and price of sheet and going deeply into application research are the main work for expending the application of aluminum alloy automotive sheet in the automobile.

  3. Eclipse mapping of accretion discs

    CERN Document Server

    Baptista, R

    2000-01-01

    The eclipse mapping method is an inversion technique that makes use of the information contained in eclipse light curves to probe the structure, the spectrum and the time evolution of accretion discs. In this review I present the basics of the method and discuss its different implementations. I summarize the most important results obtained to date and discuss how they have helped to improve our understanding of accretion physics, from testing the theoretical radial brightness temperature distribution and measuring mass accretion rates to showing the evolution of the structure of a dwarf novae disc through its outburst cycle, from isolating the spectrum of a disc wind to revealing the geometry of disc spiral shocks. I end with an outline of the future prospects.

  4. Regenerative braking control strategy in mild hybrid electric vehicles equipped with automatic manual transmission

    Institute of Scientific and Technical Information of China (English)

    QIN Datong; YE Ming; LIU Zhenjun

    2007-01-01

    The actual regenerative braking force of an integrated starter/generator (ISG),which is varied with desired braking deceleration and vehicle speed,is calculated based on an analysis of the required deceleration,maximum braking force of ISG,engine braking force and state of charge (SOC) of battery.Braking force distribution strategies are presented according to the actual regenerative braking force of ISG.To recover the vehicle's kinetic energy maximally,braking shift rules for a mild hybrid electric vehicle (HEV) equipped with automatic manual transmission (AMT) are brought forward and effects of transmission ratios are considered.A test-bed is built up and regenerative braking tests are carried out.The results show that power recovered by the braking shift rules is more than that recovered by the normal braking control rules.

  5. Market Opportunities for Automotive Components Used in Non-automotive Applications Manufacturing : Estonian Industrial Market

    OpenAIRE

    Kalajärv, Jaana

    2012-01-01

    This thesis examines the opportunities available for automotive components in the Esto-nian non-automotive industrial market. The literature review part is mainly covers the theory of marketing research, because of the approach chosen for this paper. Only small part of marketing research process is re-searched closer in literature review section, because of the scope of the research. Three most relevant steps for the thesis are chosen from research process for further more in-vestigation,...

  6. Thermal-structural coupling analysis of disk brake%盘式制动器热结构耦合分析

    Institute of Scientific and Technical Information of China (English)

    朱永梅; 朱玉君; 王新国; 张奔

    2015-01-01

    The article expresses the direct thermal-structural coupling of disk brake by Abaqus .The C3D8T ele-ment has the degrees of freedom to calculate the temperature and structure , so we mesh the 3-dimensional disk brake model with the C3D8T element and analyze the initial conditions , boundary conditions and loads on the fi-nite element model .The selection and calculation of friction coefficient , function of heat flux and convection heat transfer coefficient are discussed in detail .The temperature contours are analized and the effects of different structural and material parameters of the brake disc are compared .The analysis provides a reliable basis for choosing the disc material , designing structural size , selecting braking conditions , and preventing brake disc fail-ure .%文中应用ABAQUS软件对盘式制动器进行热结构直接耦合分析,采用具有温度计算和结构计算所需自由度的C3 D8 T单元,对制动盘三维模型划分网格;分析了有限元模型的初始条件、边界条件和载荷施加,详细讨论了制动件之间摩擦系数、热流密度函数和对流散热系数的选取和计算;分析了制动盘制动模拟过程中的温度云图,比较制动盘的不同结构和材料参数对制动盘表面温升的影响。分析结果对制动盘材料选择、结构尺寸设计、制动工况选择、制动盘破坏预防等工作提供了可靠依据。

  7. Photon Bubbles in Accretion Discs

    OpenAIRE

    Gammie, Charles F.

    1998-01-01

    We show that radiation dominated accretion discs are likely to suffer from a ``photon bubble'' instability similar to that described by Arons in the context of accretion onto neutron star polar caps. The instability requires a magnetic field for its existence. In an asymptotic regime appropriate to accretion discs, we find that the overstable modes obey the remarkably simple dispersion relation \\omega^2 = -i g k F(B,k). Here g is the vertical gravitational acceleration, B the magnetic field, ...

  8. Self-gravitating accretion discs

    OpenAIRE

    Lodato, G.

    2008-01-01

    I review recent progresses in the dynamics and the evolution of self-gravitating accretion discs. Accretion discs are a fundamental component of several astrophysical systems on very diverse scales, and can be found around supermassive black holes in Active Galactic Nuclei (AGN), and also in our Galaxy around stellar mass compact objects and around young stars. Notwithstanding the specific differences arising from such diversity in physical extent, all these systems share a common feature whe...

  9. A listening test system for automotive audio

    DEFF Research Database (Denmark)

    Christensen, Flemming; Geoff, Martin; Minnaar, Pauli;

    2005-01-01

    This paper describes a system for simulating automotive audio through headphones for the purposes of conducting listening experiments in the laboratory. The system is based on binaural technology and consists of a component for reproducing the sound of the audio system itself and a component...

  10. Metrics for Automotive Merchandising, Petroleum Marketing.

    Science.gov (United States)

    Cooper, Gloria S., Ed.; Magisos, Joel H., Ed.

    Designed to meet the job-related metric measurement needs of students in automotive merchandising and petroleum marketing classes, this instructional package is one of five for the marketing and distribution cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already know…

  11. On credibility improvements for automotive navigation systems

    NARCIS (Netherlands)

    Schaub, Florian; Hipp, Markus; Kargl, Frank; Weber, Michael

    2012-01-01

    Automotive navigation systems are becoming ubiquitous as driver assistance systems. Vendors continuously aim to enhance route guidance by adding new features to their systems. However, we found in an analysis of current navigation systems that many share interaction weaknesses, which can damage the

  12. International Conference on Vehicle and Automotive Engineering

    CERN Document Server

    Bolló, Betti

    2017-01-01

    This book presents the proceedings of the first vehicle engineering and vehicle industry conference. It captures the outcome of theoretical and practical studies as well as the future development trends in a wide field of automotive research. The themes of the conference include design, manufacturing, economic and educational topics.

  13. Aero and vibroacoustics of automotive turbochargers

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen-Schaefer, Hung [Bosch Mahle Turbo Systems GmbH, Stuttgart (Germany)

    2013-02-01

    First book about the aeroacoustics of automotive turbochargers. Author of the book ''Rotordynamics of Automotive Turbochargers'', Springer, 2012. Written by an R and D expert in the turbocharger industry. Aero and Vibroacoustics of Automotive Turbochargers is a topic involving aspects from the working fields of thermodynamics of turbomachinery, aerodynamics, rotordynamics, and noise propagation computation. In this broadly interdisciplinary subject, thermodynamics of turbomachinery is used to design the turbocharger and to determine its operating conditions. Aerodynamics is needed to study the compressor flow dynamics and flow instabilities of rotating stall and surge, which can produce growling and whining-type noises. Rotordynamics is necessary to study rotor unbalance and self-excited oil-whirl instabilities, which lead to whistling and constant tone-type noises in rotating floating oil-film type bearings. For the special case of turbochargers using ball bearings, some high-order harmonic and wear noises also manifest in the rotor operating range. Lastly, noise propagation computation, based on Lighthill's analogy, is required to investigate airborne noises produced by turbochargers in passenger vehicles. The content of this book is intended for advanced undergraduates, graduates in mechanical engineering, research scientists and practicing engineers who want to better understand the interactions between these working fields and the resulting impact on the interesting topic of Aero and Vibroacoustics of Automotive Turbochargers.

  14. Lumbar disc excision through fenestration

    Directory of Open Access Journals (Sweden)

    Sangwan S

    2006-01-01

    Full Text Available Background : Lumbar disc herniation often causes sciatica. Many different techniques have been advocated with the aim of least possible damage to other structures while dealing with prolapsed disc surgically in the properly selected and indicated cases. Methods : Twenty six patients with clinical symptoms and signs of prolapsed lumbar intervertebral disc having radiological correlation by MRI study were subjected to disc excision by interlaminar fenestration method. Results : The assessment at follow-up showed excellent results in 17 patients, good in 6 patients, fair in 2 patients and poor in 1 patient. The mean preoperative and postoperative Visual Analogue Scores were 9.34 ±0.84 and 2.19 ±0.84 on scale of 0-10 respectively. These were statistically significant (p value< 0.001, paired t test. No significant complications were recorded. Conclusion : Procedures of interlaminar fenestration and open disc excision under direct vision offers sufficient adequate exposure for lumbar disc excision with a smaller incision, lesser morbidity, shorter convalescence, early return to work and comparable overall results in the centers where recent laser and endoscopy facilities are not available.

  15. Resonances in retrograde circumbinary discs

    CERN Document Server

    Nixon, Chris

    2015-01-01

    We analyse the interaction of an eccentric binary with a circular coplanar circumbinary disc that rotates in a retrograde sense with respect to the binary. In the circular binary case, no Lindblad resonances lie within the disc and no Lindblad resonant torques are produced, as was previously known. By analytic means, we show that when the binary orbit is eccentric, there exist components of the gravitational potential of the binary which rotate in a retrograde sense to the binary orbit and so rotate progradely with respect to this disc, allowing a resonant interaction to occur between the binary and the disc. The resulting resonant torques distinctly alter the disc response from the circular binary case. We describe results of three-dimensional hydrodynamic simulations to explore this effect and categorise the response of the disc in terms of modes whose strengths vary as a function of binary mass ratio and eccentricity. These mode strengths are weak compared to the largest mode strengths expected in the prog...

  16. Counter-Rotating Accretion Discs

    CERN Document Server

    Dyda, Sergei; Ustyugova, Galina V; Romanova, Marina M; Koldoba, Alexander V

    2014-01-01

    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc center. We discuss high-resolution axisymmetric hydrodynamic simulations of a viscous counter-rotating disc for cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic $\\alpha-$viscosity including all terms in the viscous stress tensor. For the vertically separated components a shear layer forms between them. The middle of this layer free-falls to the disk center. The accretion rates are increased by factors $\\sim 10^2-10^4$ over that of a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dep...

  17. MODIFICATION OF FLAKE REINFORCED FRICTION BRAKE COMPOSITE MATERIAL

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    According to the recent development trend and need of the friction brake material, the flake reinforced friction brake material has been made out by adjusting the recipe and techniques. The two-dimensional flake vermiculite is selected as the reinforced stuffing of the material; the modified resin is used as the basal bed of the material. The tests manifest that the properties of mechanics are high, the friction coefficients are suitable and stable,and especially in high temperatures the wear is low. It is an excellent friction brake material.

  18. A model of heat dissipation for MR based brake

    Energy Technology Data Exchange (ETDEWEB)

    Wiehe, A; Noack, V; Maas, J [Hochschule Ostwestfalen-Lippe - University of Applied Sciences, Control Engineering and Mechatronics, Liebigstrasse 87, D-32657 Lemgo (Germany)], E-mail: ansgar.wiehe@hs-owl.de

    2009-02-01

    In contrast to conventional brakes actuators based on magnetorheological fluids (MRF) offer an advantage in short term, peak load decelerating. The dissipation of a high amount of energy in a short period of time results in a thermal destruction of conventional brakes. Due to the volume based energy dissipation of MR actuators, instead of the surface based energy dissipation of conventional brakes, the rise of temperature and the distribution of energy shows significant advantages. In this paper a design rule for special peak load MR actuators is derived. Furthermore the simplified model, which is the basis of the design rule, is compared to several simulation models, with different levels of detail.

  19. Disc piezoelectric ceramic transformers.

    Science.gov (United States)

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

  20. Hierarchical Control Strategy for the Cooperative Braking System of Electric Vehicle

    OpenAIRE

    Jiankun Peng; Hongwen He; Wei Liu; Hongqiang Guo

    2015-01-01

    This paper provides a hierarchical control strategy for cooperative braking system of an electric vehicle with separated driven axles. Two layers are defined: the top layer is used to optimize the braking stability based on two sliding mode control strategies, namely, the interaxle control mode and signal-axle control strategies; the interaxle control strategy generates the ideal braking force distribution in general braking condition, and the single-axle control strategy can ensure braking s...

  1. Tuning the Brake While Raising the Stake

    DEFF Research Database (Denmark)

    Meder, David; Haagensen, Brian Numelin; Hulme, Oliver

    2016-01-01

    to stop to bank the current balance. Within each gambling round, the accumulation of gains gradually increased reaction times for "continue" choices, indicating growing uncertainty in the decision to continue. Neural activity evoked by "continue" choices was associated with growing activity...... and connectivity of a cortico-subcortical "braking" network that positively scaled with the accumulated gains, including pre-supplementary motor area (pre-SMA), inferior frontal gyrus, caudate, and subthalamic nucleus (STN). The influence of the STN on continue-evoked activity in the pre-SMA was predicted...... a paradigm where subjects experienced increasing potential rewards coupled with increasing risk, this study addressed two unresolved questions in the field of decision-making: First, we investigated an "inhibitory" network of regions that has so far been investigated with externally cued action inhibition...

  2. Tribomaterial factors in space mechanism brake performance

    Science.gov (United States)

    Hawthorne, H. M.

    1990-01-01

    The asbestos/phenolic pads of Shuttle Remote Manipulator System (SRMS) brakes are unsuitable for use in long life space mechanisms because their friction decreases on extended sliding in high vacuum. Dehydration of the material and accumulation of wear debris in the conforming interface of this tribosystem induces the permanent friction changes. Other polymer and some ceramic based materials exhibit similar frictional torque behavior due to the development of minimal contact patches by the interfacial debris. In contrast, high friction occurs when other ceramics form many small contacts throughout fine debris beds. Generating this latter interfacial structure during run-in ensures that the in-vacuo friction remains stable thereafter. Such materials with low wear rates are potential candidates for friction elements in SSRMS and similar mechanisms.

  3. Comparisonal Analysis of Manuevering and Braking

    Directory of Open Access Journals (Sweden)

    Artūras Žukas

    2011-04-01

    Full Text Available This article covers the possibility of avoiding a traffic accident considering a car driver who is fallen in a dangerous situation. In such a case, the driver can choose one of the following ways: hard braking or one of the types of maneuvering, including turning off, turning with straightening or changing a line regarding road surface type (dry asphalt, wet asphalt or snowy asphalt. The article also proposes formulas for calculating road distance the car travels till dead stop. Moreover, the tables display theoretical values taking into account various car speeds and road surfaces. The pictures help with determining the most suitable type of action in light of road and weather conditions as well as car speed. The pictures clearly show the dependence of road length on movement speed. At the end of the article, conclusions are proposed.Article in Lithuanian

  4. Linear Control Technique for Anti-Lock Braking System

    Directory of Open Access Journals (Sweden)

    Chankit Jain

    2014-08-01

    Full Text Available Antilock braking systems are used in modern cars to prevent the wheels from locking after brakes are applied. The dynamics of the controller needed for antilock braking system depends on various factors. The vehicle model often is in nonlinear form. Controller needs to provide a controlled torque necessary to maintain optimum value of the wheel slip ratio. The slip ratio is represented in terms of vehicle speed and wheel rotation. In present work first of all system dynamic equations are explained and a slip ratio is expressed in terms of system variables namely vehicle linear velocity and angular velocity of the wheel. By applying a bias braking force system, response is obtained using Simulink models. Using the linear control strategies like PI-type the effectiveness of maintaining desired slip ratio is tested. It is always observed that a steady state error of 10% occurring in all the control system models.

  5. Evaluation strategy of regenerative braking energy for supercapacitor vehicle.

    Science.gov (United States)

    Zou, Zhongyue; Cao, Junyi; Cao, Binggang; Chen, Wen

    2015-03-01

    In order to improve the efficiency of energy conversion and increase the driving range of electric vehicles, the regenerative energy captured during braking process is stored in the energy storage devices and then will be re-used. Due to the high power density of supercapacitors, they are employed to withstand high current in the short time and essentially capture more regenerative energy. The measuring methods for regenerative energy should be investigated to estimate the energy conversion efficiency and performance of electric vehicles. Based on the analysis of the regenerative braking energy system of a supercapacitor vehicle, an evaluation system for energy recovery in the braking process is established using USB portable data-acquisition devices. Experiments under various braking conditions are carried out. The results verify the higher efficiency of energy regeneration system using supercapacitors and the effectiveness of the proposed measurement method. It is also demonstrated that the maximum regenerative energy conversion efficiency can reach to 88%.

  6. Deployable Engine Air-Brake for Drag Management Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ATA Engineering, Inc, proposes an SBIR program to demonstrate an innovative engine air-brake (EAB) technology that uses a deployable swirl vane mechanism to switch...

  7. Mathews Brake National Wildlife Refuge Public Use Development Plan - 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan for Mathews Brake NWR involves setting station public use goals, project a positive attitude, welcome and orient visitors, develop key resources awareness,...

  8. Handy Brake National Wildlife Refuge Habitat Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Handy Brake National Wildlife Refuge Habitat Management Plan provides a long-term vision and specific guidance on managing habitats for the resources of concern...

  9. Fishing Plan for Mathews Brake National Wildlife Refuge - 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This proposal calls for the opening of Mathews Brake NWR to sport fishing. General regulations pertaining to licenses, creel limits, and methods of taking fish will...

  10. Fishery Management Plan for Mathews Brake National Wildlife Refuge - 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This management plan was prepared by the U.S. Fish and Wildlife Service for Mathew's Brake National Wildlife Refuge. Data was provided by the refuge and area office...

  11. Fishery Management Plan for Morgan Brake National Wildlife Refuge - 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This management plan was prepared by the U. S. Fish and Wildlife Service for Morgan Brake National Wildlife Refuge. Data was provided by the Refuge and Area Office...

  12. Brake Pedal Displacement Measuring System based on Machine Vision

    Directory of Open Access Journals (Sweden)

    Chang Wang

    2013-10-01

    Full Text Available Displacement of brake pedal was an important characteristic of driving behavior. This paper proposed a displacement measure algorithm based on machine vision. Image of brake pedal was captured by camera from left side, and images were processed in industry computer. Firstly, average smooth algorithm and wavelet transform algorithm were used to smooth the original image consecutively. Then, edge extracting method which combined Roberts’s operator with wavelet analysis was used to identify the edge of brake pedal. At last, least square method was adopted to recognize the characteristic line of brake pedal’s displacement. The experimental results demonstrated that the proposed method takes the advantages of Roberts’s operator and wavelet transform, it can obtain better measurement result as well as linear displacement sensors

  13. RELIABILITY OF BRAKE SYSTEMS OF BUSES OF GROUP MAZ

    Directory of Open Access Journals (Sweden)

    A. Bessarab

    2013-01-01

    Full Text Available All over the world safety of maintained vehicles has the major value. For motor vehicles of the Republic of Belarus this problem is also actual. Maintenance of high reliability of brake systems of cars in operation is one of ways of the decision of a problem of increase of traffic safety.The analysis of reliability of brake systems of buses MAZ is carried out following the results of the state maintenance service in 2010 and the analysis of premature returns from routes of movement of buses MAZ-103 and МАZ-104 one of the motor transportation enterprises of a city of Minsk. Principal causes of structural parameters modification of brake pneumatic system of buses, the brake mechanism and elements АBS are considered.

  14. Crayfish survey at Morgan Brake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Crayfish sampling on Morgan Brake NWR for vernal crawfish and other species was done for 3 days at five sites. Data are present on species of crawfish and amphibians...

  15. Deployable Engine Air-Brake for Drag Management Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ATA Engineering, Inc., (ATA) proposes a Phase II SBIR program to demonstrate an innovative engine air-brake (EAB) technology that uses a deployable swirl vane...

  16. Morgan Brake National Wildlife Refuge Public Use Development Plan - 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan for Morgan Brake NWR involves setting station public use goals, project a positive attitude, welcome and orient visitors, develop key resources awareness,...

  17. AASPT Carbon/Carbon Aircraft Brake Disk Granted MPA

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Xi'an Chaoma Technology Co. Ltd. was issued Parts Manufacturer Approval (PMA) for Carbon/Carbon aircraft brake disk for Airbus 320 series by Civil Aviation Administration of China (CAAC). The company is held by Academy of Aerospace Solid Propulsion Technology (AASPT), a subsidiary of China Aerospace Science and Technology Corporation (CASC). It is the first approval given to a Chinese company to design and produce brakes for main civilian aircraft.

  18. FES-Assisted Walking with Spring Brake Orthosis: Simulation Studies

    OpenAIRE

    R. Jailani; Tokhi, M.O.; Gharooni, S. C.; B.S.K.K Ibrahim

    2011-01-01

    This paper presents a simulation of bipedal locomotion to generate stimulation pulses for activating muscles for paraplegic walking with wheel walker using functional electrical stimulation (FES) with spring brake orthosis (SBO). A new methodology for paraplegic gait, based on exploiting natural dynamics of human gait, is introduced. The work is a first effort towards restoring natural like swing phase in paraplegic gait through a new hybrid orthosis, referred to as spring brake orthosis (SBO...

  19. OPTIMAL EMERGENCY VEHICLE BRAKING CONTROL BASED ON DYNAMIC FRICTION MODEL

    Directory of Open Access Journals (Sweden)

    L. Olmos

    2005-04-01

    Full Text Available A dynamic friction model for the tire-road interface is used in an optimal control scheme for emergency braking ofvehicles. The controller sets a target relative velocity curve that the vehicle must track in order to achieve braking inminimum time. It is shown that this curve corresponds to the solution of a minimum time optimal control problem.The final goal of the control is to improve the safety levels in highway transportation.

  20. Brake subharmonic solutions of first order Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,we mainly use the Galerkin approximation method and the iteration inequalities of the L-Maslov type index theory to study the properties of brake subharmonic solutions for the first order non-autonomous Hamiltonian systems.We prove that when the positive integers j and k satisfy the certain conditions,there exists a jT-periodic nonconstant brake solution zj such that zj and zkj are distinct.

  1. Investigation of aerodynamic braking devices for wind turbine applications

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, D.A. [R. Lynette & amp; Associates, Seattle, WA (United States)

    1997-04-01

    This report documents the selection and preliminary design of a new aerodynamic braking system for use on the stall-regulated AWT-26/27 wind turbines. The goal was to identify and design a configuration that offered improvements over the existing tip brake used by Advanced Wind Turbines, Inc. (AWT). Although the design objectives and approach of this report are specific to aerodynamic braking of AWT-26/27 turbines, many of the issues addressed in this work are applicable to a wider class of turbines. The performance trends and design choices presented in this report should be of general use to wind turbine designers who are considering alternative aerodynamic braking methods. A literature search was combined with preliminary work on device sizing, loads and mechanical design. Candidate configurations were assessed on their potential for benefits in the areas of cost, weight, aerodynamic noise, reliability and performance under icing conditions. As a result, two configurations were identified for further study: the {open_quotes}spoiler-flap{close_quotes} and the {open_quotes}flip-tip.{close_quotes} Wind tunnel experiments were conducted at Wichita State University to evaluate the performance of the candidate aerodynamic brakes on an airfoil section representative of the AWT-26/27 blades. The wind tunnel data were used to predict the braking effectiveness and deployment characteristics of the candidate devices for a wide range of design parameters. The evaluation was iterative, with mechanical design and structural analysis being conducted in parallel with the braking performance studies. The preliminary estimate of the spoiler-flap system cost was $150 less than the production AWT-26/27 tip vanes. This represents a reduction of approximately 5 % in the cost of the aerodynamic braking system. In view of the preliminary nature of the design, it would be prudent to plan for contingencies in both cost and weight.

  2. Prosthetic Lumbar disc replacement for degenerative disc disease

    Directory of Open Access Journals (Sweden)

    Kulkarni Arvind

    2005-01-01

    Full Text Available Mechanical articulated device to replace intervertebral disc as a treatment for low back pain secondary to disc degeneration has emerged as a promising tool for selected patients. The potential advantages are prevention of adjacent segment degeneration, maintenance of mobility as well as avoidance of all the complications associated with fusion. The short-term results have been comparable to that of fusion, a few mid-term results have shown mixed outcome, but information on long-term results and performance are not available at present. The rationale for lumbar disc arthroplasty, indications, contraindications, the various artificial devices in the market and the concepts intrinsic to each of them, basic technique of insertion, complications are discussed and a brief summary of our experience with one of the devices is presented.

  3. Design and development of coil casing MRF brake system

    Directory of Open Access Journals (Sweden)

    Siti Lydia R.

    2017-01-01

    Full Text Available Nowadays magneto-rheological brakes has been introduce to overcome the drawback of conventional braking such as bulky, leakage and late build up pressure. Magnetic field is a main parameter need to be maximized in order to increase the efficiency of the brake. In MRF brake system the magnetic field directly affected by coil casing shapes. This paper focused on the study of the effect of coil casing shapes to the magnetic field distribution in MR brake. Finite Element Method will be used to analyze the magnetic field distribution produced by the coil. Five coils shape that different angle from 50° to 90° used in this study. As the result magnetic field was change quadratically by increasing the angle size. The best angle is between 60° to 70°. The peak value is at 70°. If more than that the magnetic field will drop. The significant of this study is to get the most efficient angle for the electromagnet casing for the MR brakes.

  4. Development of automobile brake lining using pulverized cow hooves

    Directory of Open Access Journals (Sweden)

    Katsina C. BALA

    2016-06-01

    Full Text Available Asbestos has been used for so long as automobile brake lining material because of its good physical and chemical properties. However, due to the health hazard associated with its handling, it has lost favour and several alternative materials are being increasingly used. Asbestos-free brake lining was developed in this work using pulverized cow hooves along with epoxy resin, barium sulphate, graphite and aluminium oxide. This was with a view to exploiting the characteristics of cow hooves, which are largely discarded as waste materials to replace asbestos which has been found to be carcinogenic. Samples of brake linings were produced using compressive moulding in which the physical and mechanical properties of the samples were studied. The results obtained showed that proper bonding was achieved as the percentage by weight of epoxy resin increased and percentage by weight of pulverized cow hooves decreased. The hardness, compressive strength, coefficient of friction, water and oil absorption, relative density and wear rate of the brake linings were determined and compared with existing brake lining properties. The result indicates that pulverized cow hooves can be used as brake lining material for automobiles.

  5. Regenerative Braking Algorithm for an ISG HEV Based on Regenerative Torque Optimization

    Institute of Scientific and Technical Information of China (English)

    XIAO Wen-yong; WANG Feng; ZHUO Bin

    2008-01-01

    A novel regenerative braking algorithm based on regenerative torque optimization with emulate engine compression braking (EECB) was proposed to make effective and maximum use of brake energy in order to improve fuel economy. The actual brake oil pressure of driving wheel which is reduced by the amount of the regenerative braking force is supplied from the electronic hydraulic brake system. Regenerative torque optimization maximizes the actual regenerative power recuperation by energy storage component, and EECB is a useful extended type of regenerative braking. The simulation results show that actual regenerative power recuperation for the novel regenerative braking algorithm is more than using conventional one, and life-span of brake disks is prolonged for the novel algorithm.

  6. Lightweight Steel Solutions for Automotive Industry

    Science.gov (United States)

    Lee, Hong Woo; Kim, Gyosung; Park, Sung Ho

    2010-06-01

    Recently, improvement in fuel efficiency and safety has become the biggest issue in worldwide automotive industry. Although the regulation of environment and safety has been tightened up more and more, the majority of vehicle bodies are still manufactured from stamped steel components. This means that the optimized steel solutions enable to demonstrate its ability to reduce body weight with high crashworthiness performance instead of expensive light weight materials such as Al, Mg and composites. To provide the innovative steel solutions for automotive industry, POSCO has developed AHSS and its application technologies, which is directly connected to EVI activities. EVI is a technical cooperation program with customer covering all stages of new car project from design to mass production. Integrated light weight solutions through new forming technologies such as TWB, hydroforming and HPF are continuously developed and provided for EVI activities. This paper will discuss the detailed status of these technologies especially light weight steel solutions based on innovative technologies.

  7. Springback prediction of TWIP automotive sheets

    Science.gov (United States)

    Ahn, Kanghwan; Yoo, Donghoon; Seo, Min Hong; Park, Sung-Ho; Chung, Kwansoo

    2009-08-01

    In an effort to reduce the weight of vehicles, automotive companies are replacing conventional steel parts with light weight alloys and/or with advanced high strength steels (AHSS) such as dual-phase (DP), twinning induced plasticity (TWIP), and transformation induced plasticity (TRIP) steels. The main objective of this work is to experimentally and numerically evaluate the macro-performance of the automotive TWIP sheet in conjunction with springback. In order to characterize the mechanical properties, simple tension and tension-compression tests were performed to determine anisotropic properties, as well as the Bauschinger, transient, and permanent softening behaviors during reverse loading. For numerical simulations, the anisotropic yield function Yld2000-2d was utilized along with the combined isotropic-kinematic hardening law based on the modified Chaboche model. Springback verification was performed for the unconstrained cylindrical bending and 2D draw bending tests.

  8. Development of light metals automotive structural subsystems

    Energy Technology Data Exchange (ETDEWEB)

    Luo, A.A.; Sachdev, A.K. [General Motors Research and Development Center, Warren, MI (United States)

    2007-07-01

    Key technological developments in aluminum and magnesium alloys were reviewed in relation to the manufacturing processes that enable lightweight automotive structural subsystems. Examples included the materials and processes evolution of lightweight body structures, chassis systems, and instrument panel beams. New aluminum and magnesium alloys and manufacturing technologies used to reduce mass and improve performance in vehicle cradle structures were discussed. Hydroforming processes used to enable the use of lightweight aluminum alloy tubes in automotive body structures were also reviewed, in addition to body architectures enabled by different materials and manufacturing processes. The review noted that magnesium instrument panels are now being designed to provide significant performance improvement, reduced vibration, and enhanced crashworthiness in new automobiles. It was concluded that vehicles will incorporate more lightweight materials such as nanocomposites and aluminum and magnesium sheets. 9 refs., 10 figs.

  9. Green innovation adoption in automotive supply chain

    DEFF Research Database (Denmark)

    Zailani, Suhaiza; Govindan, Kannan; Iranmanesh, Mohammad;

    2015-01-01

    using the partial least squares technique. Environmental regulations, market demand, and firm internal initiatives have a positive effect on green innovation initiatives (GII), while GIIs have a positive effect on the three categories of sustainable performance (i.e., environmental, social, and economic......Green innovation has currently been receiving a great deal of international attention because of the growing concern of consumers, governments, and the community as a whole with regard to the degradation of natural resources and environmental pollution. The automotive sector is one of the leading...... generators of industrial waste that affect the quality of the natural environment. This study aims to investigate the determinants of green innovation adoption and its effect on firm performance. Data were gathered by surveying 153 firms in the Malaysian automotive supply chain industry. Data were analyzed...

  10. Platform Based Design for Automotive Sensor Conditioning

    CERN Document Server

    Fanucci, L; Iozzi, F; Marino, C; Rocchi, A

    2011-01-01

    In this paper a general architecture suitable to interface several kinds of sensors for automotive applications is presented. A platform based design approach is pursued to improve system performance while minimizing time-to-market.. The platform is composed by an analog front-end and a digital section. The latter is based on a microcontroller core (8051 IP by Oregano) plus a set of dedicated hardware dedicated to the complex signal processing required for sensor conditioning. The microcontroller handles also the communication with external devices (as a PC) for data output and fast prototyping. A case study is presented concerning the conditioning of a Gyro yaw rate sensor for automotive applications. Measured performance results outperform current state-of-the-art commercial devices.

  11. Polymer matrix nanocomposites for automotive structural components

    Science.gov (United States)

    Naskar, Amit K.; Keum, Jong K.; Boeman, Raymond G.

    2016-12-01

    Over the past several decades, the automotive industry has expended significant effort to develop lightweight parts from new easy-to-process polymeric nanocomposites. These materials have been particularly attractive because they can increase fuel efficiency and reduce greenhouse gas emissions. However, attempts to reinforce soft matrices by nanoscale reinforcing agents at commercially deployable scales have been only sporadically successful to date. This situation is due primarily to the lack of fundamental understanding of how multiscale interfacial interactions and the resultant structures affect the properties of polymer nanocomposites. In this Perspective, we critically evaluate the state of the art in the field and propose a possible path that may help to overcome these barriers. Only once we achieve a deeper understanding of the structure-properties relationship of polymer matrix nanocomposites will we be able to develop novel structural nanocomposites with enhanced mechanical properties for automotive applications.

  12. Innovation and Entrepreneurship in the Automotive Business

    DEFF Research Database (Denmark)

    2011-01-01

    invention have appropriate benefits. The timing of the dialog with a potential user or business partner is important when it comes to which issues that have highest priorities or are most frequently discussed in the organization of said user or business partner. If there exist a special issue that your idea......The global automotive business is one of the most competitive environment you can imagine. As an independent inventor or as a small development company it is very challenging to be successful in implementing new ideas and components. In this mature and somewhat conservative technical environment...... address you will have a much better access the decision making process and get enough interest for a potential business deal. After 20 years as a supplier of engineering services to the automotive industry and 10 years as head of Global R&D at Scania CV AB, I have experienced pros and cons both from...

  13. Black hole accretion disc impacts

    CERN Document Server

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  14. Atomic gas in debris discs

    Science.gov (United States)

    Hales, Antonio S.; Barlow, M. J.; Crawford, I. A.; Casassus, S.

    2017-04-01

    We have conducted a search for optical circumstellar absorption lines in the spectra of 16 debris disc host stars. None of the stars in our sample showed signs of emission line activity in either Hα, Ca II or Na I, confirming their more evolved nature. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines (when Na I D data were available). We analyse the characteristics of these spectral features to determine whether they are of circumstellar or interstellar origins. The strongest evidence for circumstellar gas is seen in the spectrum of HD 110058, which is known to host a debris disc observed close to edge-on. This is consistent with a recent ALMA detection of molecular gas in this debris disc, which shows many similarities to the β Pictoris system.

  15. Coevolution of binaries and circumbinary gaseous discs

    Science.gov (United States)

    Fleming, David P.; Quinn, Thomas R.

    2017-01-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  16. MICROALLOYED STEELS FOR THE AUTOMOTIVE INDUSTRY

    OpenAIRE

    Debanshu Bhattacharya

    2014-01-01

    Two major drivers for the use of newer steels in the automotive industry are fuel efficiency and increased safety performance. Fuel efficiency is mainly a function of weight of steel parts, which in turn, is controlled by gauge and design. Safety is determined by the energy absorbing capacity of the steel used to make the part. All of these factors are incentives for the U.S. automakers to use both Highly Formable and Advanced High Strength Steels (AHSS) to replace the conventional ...

  17. INNOVATION LEAN PRINCIPLES IN AUTOMOTIVE GREEN MANUFACTURING

    Directory of Open Access Journals (Sweden)

    Dušan Sabadka

    2014-12-01

    Full Text Available Today, industries such as automotive and manufacturing industries deal with a lot of environmental regulations. Lean is a production strategy whose fundamental principles drive the industry towards a more effective production of goods and services. The eco-efficiency concept is primary to sustainable development and intends to provide more value with less environmental impact. The aim of this study is to identify and explore the contributions of Lean to reduce environmental impacts that naturally result from industrial activity.

  18. Characterization of three-way automotive catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kenik, E.A.; More, K.L. [Oak Ridge National Lab., TN (United States); LaBarge, W. [Delphi Automotive Systems, Flint, MI (United States)] [and others

    1997-04-01

    The CRADA between Delphi Automotive Systems (Delphi; formerly General Motors - AC Delco, Systems) and Lockheed Martin Energy Research (LMER) on automotive catalysts was completed at the end of FY96, after a ten month, no-cost extension. The CRADA was aimed at improved performance and lifetime of noble metal based three-way-catalysts (TWC), which are the primary catalytic system for automotive emission control systems. While these TWC can meet the currently required emission standards, higher than optimum noble metal loadings are often required to meet lifetime requirements. In addition, more stringent emission standards will be imposed in the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts. Initially in a fresh catalyst, the active material is often distributed on a very fine scale, approaching single atoms or small atomic clusters. As such, a wide range of analytical techniques have been employed to provide high spatial resolution characterization of the evolving state of the catalytic material.

  19. Vertebral osteomyelitis without disc involvement

    Energy Technology Data Exchange (ETDEWEB)

    Kamani, I.; Syed, I.; Saifuddin, A. E-mail: asaifuddin@aol.com; Green, R.; MacSweeney, F

    2004-10-01

    Vertebral osteomyelitis is most commonly due to pyogenic or granulomatous infection and typically results in the combined involvement of the intervertebral disc and adjacent vertebral bodies. Non-infective causes include the related conditions of chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. Occasionally, these conditions may present purely within the vertebral body, resulting in various combinations of vertebral marrow oedema and sclerosis, destructive lesions of the vertebral body and pathological vertebral collapse, thus mimicking neoplastic disease. This review illustrates the imaging features of vertebral osteomyelitis without disc involvement, with emphasis on magnetic resonance imaging (MRI) findings.

  20. Electro-mechanical Braking Method in Hybrid Electric Vehicles Based on Feedback Control Theory

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; YU Jun-quan; LIU Zheng-yu; CHANG Cheng

    2014-01-01

    In this paper, the hybrid electric vehicle braking process is researched, by using variables consists of HEV speed, motor speed, and state of charge established, functions of mechanical braking force, regenerative braking force and efficiency of energy recovery are constructed, and the control goal is to maximization the energy recovery efficiency. Under the feedback control strategy, with the constrain condition of braking strength and braking stability, combining experiments in ADVISOR, in different experiments of different working conditions, we can see that in UDDS Cycle, the regenerative braking efficiency is the best. What’s more, compared with strategies in ADVISOR, strategy proposed in this paper is obviously better.