WorldWideScience

Sample records for braking radiation

  1. Radiative braking in the extended exosphere of GJ436b

    CERN Document Server

    Bourrier, Vincent; Etangs, Alain Lecavelier des

    2015-01-01

    The recent detection of a giant exosphere surrounding the warm Neptune GJ436 b has shed new light on the evaporation of close-in planets, revealing that moderately irradiated, low-mass exoplanets could make exceptional targets for studying this mechanism and its impact on the exoplanet population. Three HST/STIS observations were performed in the Lyman-$\\alpha$ line of GJ436 at different epochs, showing repeatable transits with large depths and extended durations. Here, we study the role played by stellar radiation pressure on the structure of the exosphere and its transmission spectrum. We found that the neutral hydrogen atoms in the exosphere of GJ436 b are not swept away by radiation pressure as shown to be the case for evaporating hot Jupiters. Instead, the low radiation pressure from the M-dwarf host star only brakes the gravitational fall of the escaping hydrogen toward the star and allows its dispersion within a large volume around the planet, yielding radial velocities up to about -120 km s$^{-1}$ tha...

  2. Theoretical and experimental study of an energy-reinforced braking radiation photon beam

    International Nuclear Information System (INIS)

    This research thesis reports the theoretical study of a photon beam raised towards high energies, its experimental implementation, the definition of a gamma spectrometry method which aimed at checking various hypotheses used in the beam theoretical study. After a presentation of the theory of phenomena of electron braking radiation, of materialisation of photons into positon-negaton pair, and of issues related to multiple Coulomb diffusion, the author reports the study of the different solutions which allow a photon beam to be obtained. A braking radiation of mono-kinetic electron has been used. This braking radiation is reinforced by absorption of low energy protons in a column of lithium hydride. The author describes how the beam is built up, and the experimental approach. He describes how raw data are processed to get rid of the influence of the multiple Coulomb diffusion and of the braking radiation. Experimental results are compared with those obtained by convolution of photon spectra and differential cross section

  3. Angular Momentum Loss by Magnetic Braking and Gravitational Radiation in Relativistic Binary Stars

    CERN Document Server

    Yakut, K; Tout, C A

    2008-01-01

    Angular momentum loss (AML) mechanisms and dynamical evolution owing to magnetic braking and gravitational radiation in relativistic binary stars (RBS) are studied with use of physical parameters collected from the literature. We have calculated and compared AML time scales for the RBS with non-degenerate components and double degenerate (DD) systems.

  4. Nomograms for calculation of defence from braking radiation

    CERN Document Server

    Bespalov, V I; Shtejn, M M

    2002-01-01

    More precise nomograms for calculation of thickness of shielding against direct Bremsstrahlung are obtained with taking account of recently introduced radiation safety standards and disadvantages of earlier used simplified nomograms. The nomograms are built for three shielding materials (lead, iron, concrete) for 16 angular of radiation exit in the range of 0-180 deg and 22 values of electron energy within the interval of 0.5-15 MeV. A special computer program, is developed to calculate the radiation protection parameters using a great set of nomograms proposed

  5. 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.

  6. An evaporating planet in the wind: stellar wind interactions with the radiatively braked exosphere of GJ436 b

    CERN Document Server

    Bourrier, Vincent; Ehrenreich, David; Tanaka, Yuki A; Vidotto, Aline A

    2016-01-01

    The warm Neptune GJ436b was observed with HST/STIS at three different epochs in the stellar Ly-alpha line, showing deep, repeated transits caused by a giant exosphere of neutral hydrogen. The low radiation pressure from the M-dwarf host star was shown to play a major role in the dynamics of the escaping gas. Yet by itself it cannot explain the time-variable spectral features detected in each transit. Here we investigate the combined role of radiative braking and stellar wind interactions using numerical simulations with the EVaporating Exoplanet code (EVE) and we derive atmospheric and stellar properties through the direct comparison of simulated and observed spectra. Our simulations match the last two epochs well. The observed sharp early ingresses come from the abrasion of the planetary coma by the stellar wind. Spectra observed during the transit can be produced by a dual exosphere of planetary neutrals (escaped from the upper atmosphere of the planet) and neutralized protons (created by charge-exchange wi...

  7. An evaporating planet in the wind: stellar wind interactions with the radiatively braked exosphere of GJ 436 b

    Science.gov (United States)

    Bourrier, V.; Lecavelier des Etangs, A.; Ehrenreich, D.; Tanaka, Y. A.; Vidotto, A. A.

    2016-06-01

    Observations of the warm Neptune GJ 436 b were performed with HST/STIS at three different epochs (2012, 2013, 2014) in the stellar Lyman-α line. They showed deep, repeated transits that were attributed to a giant exosphere of neutral hydrogen. The low radiation pressure from the M-dwarf host star was shown to play a major role in the dynamics of the escaping gas and its dispersion within a large volume around the planet. Yet by itself it cannot explain the specific time-variable spectral features detected in each transit. Here we investigate the combined role of radiative braking and stellar wind interactions using numerical simulations with the EVaporating Exoplanet code (EVE) and we derive atmospheric and stellar properties through the direct comparison of simulated and observed spectra. The first epoch of observations is difficult to interpret because of the lack of out-of-transit data. In contrast, the results of our simulations match the observations obtained in 2013 and 2014 well. The sharp early ingresses observed in these epochs come from the abrasion of the planetary coma by the stellar wind. Spectra observed at later times during the transit can be produced by a dual exosphere of planetary neutrals (escaped from the upper atmosphere of the planet) and neutralized protons (created by charge-exchange with the stellar wind). We find similar properties at both epochs for the planetary escape rate (~2.5 × 108 g s-1), the stellar photoionization rate (~2 × 10-5 s-1), the stellar wind bulk velocity (~85 km s-1), and its kinetic dispersion velocity (~10 km s-1, corresponding to a kinetic temperature of 12 000 K). We also find high velocities for the escaping gas (~50-60 km s-1) that may indicate magnetohydrodynamic (MHD) waves that dissipate in the upper atmosphere and drive the planetary outflow. In 2014 the high density of the stellar wind (~3 × 103 cm-3) led to the formation of an exospheric tail that was mainly composed of neutralized protons and produced

  8. 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...

  9. TGV disc brake squeal

    Science.gov (United States)

    Lorang, X.; Foy-Margiocchi, F.; Nguyen, Q. S.; Gautier, P. E.

    2006-06-01

    The discomfort generated by the noise emission of braking systems in trains has aroused recently many studies on the mechanical modelling of brake noise in France. A theoretical and numerical discussion on the phenomenon of brake squeal is given in this paper in relation with some experimental data. This study is based upon a flutter instability analysis giving unstable modes of the brake system under the contact and Coulomb friction.

  10. Experimental Identification of Brake Pad Material Properties—A Step Towards a Better Prediction of Brake Squeal

    Science.gov (United States)

    Hornig, Sylwia; Hochlenert, Daniel; von Wagner, Utz

    2010-09-01

    Automotive brake squeal is a disruptive high frequency sound radiation phenomenon generated by friction-induced self-excited vibrations of the brake system. The brake system loses its stability and starts oscillating in a limit cycle with amplitudes limited by nonlinearities, the main origin of the nonlinearities being brake lining material. In order to perform a reliable brake squeal prediction using established mathematical-mechanical models, the knowledge of the lining material properties is of great importance. The present paper deals with the experimental identification of lining material properties, expecially referring to the elastic properties. Since these strongly vary depending on the operating conditions of brake systems, it is necessary to reproduce the operating conditions during brake squeal as close as possible in experimental setups. In this context a special test rig, the test data evaluation and the experimentally determined nonlinear elastic brake lining properties are presented. Assuming these brake lining properties to be the prominent source of the nonlinearity, a nonlinear stability analysis is performed on a realistic disk brake model. The results referring to brake squeal are discussed, whereas basic phenomena known from operating experience of brake systems can be explained on the basis of this analysis.

  11. Pulsar Braking Indices Revisited

    CERN Document Server

    Johnston, S; Johnston, Simon; Galloway, David

    1999-01-01

    Using the standard equation for the slowdown of a neutron star, we derive a formula for the braking index via integration rather than the conventional differentiation. The new formula negates the need to measure the second time derivative of the rotation frequency. We show that the method gives similar braking indices for PSR B1509-58 and the Crab pulsar to those already in the literature. We point out that our method is useful for obtaining the braking indices of moderate aged pulsars without the need for long, phase-connected timing solutions. We applied the method to 20 pulsars and discuss the implications of the results. We find that virtually all the derived braking indices are dominated by the effects of (unseen) glitches, the recovery from which corrupts the value of the frequency first derivative. However, any real, large, positive braking index has implications for magnetic field decay and offers support to recent models of pulsar evolution.

  12. Probing the wind-wind collision in Gamma Velorum with high-resolution Chandra X-ray spectroscopy: evidence for sudden radiative braking and non-equilibrium ionization

    CERN Document Server

    Henley, D B; Pittard, J M

    2004-01-01

    We present a new analysis of an archived Chandra HETGS X-ray spectrum of the WR+O colliding wind binary Gamma Velorum. The spectrum is dominated by emission lines from astrophysically abundant elements: Ne, Mg, Si, S and Fe. From a combination of broad-band spectral analysis and an analysis of line flux ratios we infer a wide range of temperatures in the X-ray emitting plasma (~4-40 MK). As in the previously published analysis, we find the X-ray emission lines are essentially unshifted, with a mean FWHM of 1240 +/- 30 km/s. Calculations of line profiles based on hydrodynamical simulations of the wind-wind collision predict lines that are blueshifted by a few hundred km/s. The lack of any observed shift in the lines may be evidence of a large shock-cone opening half-angle (> 85 degrees), and we suggest this may be evidence of sudden radiative braking. From the R and G ratios measured from He-like forbidden-intercombination-resonance triplets we find evidence that the Mg XI emission originates from hotter gas c...

  13. WIND BRAKING OF MAGNETARS

    Energy Technology Data Exchange (ETDEWEB)

    Tong, H. [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China); Xu, R. X.; Qiao, G. J. [KIAA and School of Physics, Peking University, Beijing 100871 (China); Song, L. M., E-mail: tonghao@xao.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2013-05-10

    We explore the wind braking of magnetars considering recent observations challenging the traditional magnetar model. There is evidence for strong multipole magnetic fields in active magnetars, but the dipole field inferred from spin-down measurements may be strongly biased by particle wind. Recent observations challenging the traditional model of magnetars may be explained naturally by the wind braking scenario: (1) the supernova energies of magnetars are of normal value; (2) the non-detection in Fermi observations of magnetars; (3) the problem posed by low magnetic field soft gamma-ray repeaters; (4) the relation between magnetars and high magnetic field pulsars; and (5) a decreasing period derivative during magnetar outbursts. Transient magnetars with L{sub x}<- E-dot{sub rot} may still be magnetic dipole braking. This may explain why low luminosity magnetars are more likely to have radio emissions. A strong reduction of the dipole magnetic field is possible only when the particle wind is very collimated at the star surface. A small reduction of the dipole magnetic field may result from detailed considerations of magnetar wind luminosity. In the wind braking scenario, magnetars are neutron stars with a strong multipole field. For some sources, a strong dipole field may no longer be needed. A magnetism-powered pulsar wind nebula will be one of the consequences of wind braking. For a magnetism-powered pulsar wind nebula, we should see a correlation between the nebula luminosity and the magnetar luminosity. Under the wind braking scenario, a braking index smaller than three is expected. Future braking index measurement of a magnetar may tell us whether magnetars are wind braking or magnetic dipole braking.

  14. WIND BRAKING OF MAGNETARS

    International Nuclear Information System (INIS)

    We explore the wind braking of magnetars considering recent observations challenging the traditional magnetar model. There is evidence for strong multipole magnetic fields in active magnetars, but the dipole field inferred from spin-down measurements may be strongly biased by particle wind. Recent observations challenging the traditional model of magnetars may be explained naturally by the wind braking scenario: (1) the supernova energies of magnetars are of normal value; (2) the non-detection in Fermi observations of magnetars; (3) the problem posed by low magnetic field soft gamma-ray repeaters; (4) the relation between magnetars and high magnetic field pulsars; and (5) a decreasing period derivative during magnetar outbursts. Transient magnetars with Lxrot may still be magnetic dipole braking. This may explain why low luminosity magnetars are more likely to have radio emissions. A strong reduction of the dipole magnetic field is possible only when the particle wind is very collimated at the star surface. A small reduction of the dipole magnetic field may result from detailed considerations of magnetar wind luminosity. In the wind braking scenario, magnetars are neutron stars with a strong multipole field. For some sources, a strong dipole field may no longer be needed. A magnetism-powered pulsar wind nebula will be one of the consequences of wind braking. For a magnetism-powered pulsar wind nebula, we should see a correlation between the nebula luminosity and the magnetar luminosity. Under the wind braking scenario, a braking index smaller than three is expected. Future braking index measurement of a magnetar may tell us whether magnetars are wind braking or magnetic dipole braking.

  15. Wind Braking of Magnetars

    Science.gov (United States)

    Tong, H.; Xu, R. X.; Song, L. M.; Qiao, G. J.

    2013-05-01

    We explore the wind braking of magnetars considering recent observations challenging the traditional magnetar model. There is evidence for strong multipole magnetic fields in active magnetars, but the dipole field inferred from spin-down measurements may be strongly biased by particle wind. Recent observations challenging the traditional model of magnetars may be explained naturally by the wind braking scenario: (1) the supernova energies of magnetars are of normal value; (2) the non-detection in Fermi observations of magnetars; (3) the problem posed by low magnetic field soft gamma-ray repeaters; (4) the relation between magnetars and high magnetic field pulsars; and (5) a decreasing period derivative during magnetar outbursts. Transient magnetars with L_x{rot may still be magnetic dipole braking. This may explain why low luminosity magnetars are more likely to have radio emissions. A strong reduction of the dipole magnetic field is possible only when the particle wind is very collimated at the star surface. A small reduction of the dipole magnetic field may result from detailed considerations of magnetar wind luminosity. In the wind braking scenario, magnetars are neutron stars with a strong multipole field. For some sources, a strong dipole field may no longer be needed. A magnetism-powered pulsar wind nebula will be one of the consequences of wind braking. For a magnetism-powered pulsar wind nebula, we should see a correlation between the nebula luminosity and the magnetar luminosity. Under the wind braking scenario, a braking index smaller than three is expected. Future braking index measurement of a magnetar may tell us whether magnetars are wind braking or magnetic dipole braking.

  16. Problems of perception of radiation risk as a brake of the development of nuclear industry in Belarus

    International Nuclear Information System (INIS)

    Full text: The development of nuclear industry is very important task for Belarus, for the country without own alternative sources of energy. At the same time this task is difficult for country that is one of the most suffered form Chernobyl accident. Psychological distress arising from the accident and its aftermath has had a profound impact on individual and community perception of radiation risk by population of Belarus. Although accurate information is accessible and many attempts at dissemination have made, the gloomy stereotype of Chernobyl has developed in public consciousness. At the present day misconceptions and myths about the threat of radiation persist, promoting a paralyzing fatalism among resident in questions of the development of nuclear industry in Belarus. People still lack the information they need about real radiation risk. In such situation good-quality, in time and correctly sent information can be very important in system of measures on reduction of a mental and emotional pressure, on preparation of the population for the decision of socio-economic problems. The creation of uniform information system with use of resources of a global computer network is accepted as new innovation ways of increase of the public knowledge about radiation danger. The creation of such system will allow to carry out by the most modern methods uniform information and socially-rehabilitation politics directed on formation and education of the population in the field of radiating safety and radioecology, on overcoming socially-psychological stress and radio phobia, increase of the vital activity, the formation of a safe image of the life, i.e. on overcoming of consequences of Chernobyl accident in consciousness of the people. (author)

  17. 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.

  18. 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.

  19. 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.

  20. Development of brake assist system. Summary of hydraulic brake assist system; Brake assist system no kaihatsu. Ekiatsushiki brake assist system no gaiyo

    Energy Technology Data Exchange (ETDEWEB)

    Hara, M.; Ota, M.; Shimizu, S. [Toyota, Motor Corp., Aichi (Japan)

    1997-10-01

    We have already developed vacuum-booster-type Brake Assist System that supplies additional braking power when panic braking is recognized. We are convinced that the expansion of Brake Assist System will become more important issue in the future. Therefore we have developed hydraulic Brake Assist System with increasing its controllability and reducing its discomfort. This system have a brake pressure sensor to detect emergency braking operation and an antilock device to supply additional braking power. 8 refs., 11 figs.

  1. Development of mechanical brake assist; Mechanical brake assist no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, M.; Shingyoji, S.; Nakamura, I.; Tagawa, T.; Saito, Y.; Ishihara, T.; Kobayashi, S.; Yoshida, M. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    We have recognized that there are drivers who cannot apply strong brake pedal force , in spite of the necessity of hard braking in emergencies. We have developed a `mechanical brake assist system` which assists drivers appropriately, according to the drivers` characteristics based on studying the characteristic`s of conditions of drivers applying the brake pedal force in emergency conditions. 2 refs., 7 figs., 1 tab.

  2. 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...

  3. New Phase-coherent Measurements of Pulsar Braking Indices

    CERN Document Server

    Livingstone, M A; Gavriil, F P; Manchester, R N; Gotthelf, E V; Kuiper, L; Livingstone, Margaret A.; Kaspi, Victoria M.; Gavriil, Fotis P.; Manchester, Richard N.; Kuiper, Lucien

    2007-01-01

    Pulsar braking indices offer insight into the physics that underlies pulsar spin-down. Only five braking indices have been measured via phase-coherent timing; all measured values are less than 3, the value expected from magnetic dipole radiation. Here we present new measurements for three of the five pulsar braking indices, obtained with phase-coherent timing for PSRs J1846-0258 (n=2.65+/-0.01), B1509-58 (n=2.839+/-0.001) and B0540-69 (n=2.140+/-0.009). We discuss the implications of these results and possible physical explanations for them.

  4. Development of combined brake system on front and rear brakes for scooter; Scooter yo zenkorin rendo brake system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, Y.; Itabashi, T.; Shinohara, S.; Honda, Y. [Honda R and D Co. Ltd., Tokyo (Japan)

    1997-10-01

    Scooters need appropriate front and rear wheel braking power distribution and each of front and rear brakes have been operated using right and left levers. This time, a low cost brakes with cable type combined brake system for small size scooter and a brakes with hydraulic type combined brake system for middle size scooter have been developed to obtain appropriate front and rear wheel braking power distribution. Both systems use convenient left lever to operate. 3 refs., 9 figs., 1 tab.

  5. Wind braking of magnetars

    CERN Document Server

    Tong, H; Song, L M; Qiao, G J

    2012-01-01

    Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are magnetar candidates. During their studies, the magnetic dipole braking mechanism is often assumed. This will result in a high surface dipole field for most AXPs and SGRs. It will also bring several problems challenging the magnetar interpretation. Alternatively, it is possible that AXPs and SGRs are braked down by a particle wind which also originates from magnetic field decay. In the wind braking scenario, magnetars are neutron stars with strong multipole field. A strong dipole field is no longer required. Recent challenging observations of magnetars may be explained naturally in the wind braking scenario: (1) The supernova energetics of those associated with magnetars are of normal value; (2) The non-detection in Fermi observations of magnetars; (3) The problem posed by the low-magnetic field soft gamma-ray repeater; (4) The relation between magnetars and high magnetic field pulsars ; (5) A decreasing period derivative during magnetar ou...

  6. Comparative analysis into the tractor-trailer braking dynamics: tractor with single axle brakes, tractor with all wheel brakes

    Science.gov (United States)

    Nastasoiu, Mircea; Ispas, Nicolae

    2014-06-01

    The paper elaborates a mathematical model in order to conduct a study into the dynamics of tractor-trailer systems during braking. The braking dynamics is analyzed by considering two versions for the braking system: 1) braking applied on the rear axle and 2) braking applied on all four wheels. In both versions the trailer is braked on all wheels. The mathematical model enables us to determine and graphically illustrate the evolution of the following parameters: braking deceleration, braking speed and the distance traveled by the tractor during braking. The mathematical model elaborated is applied on a tractor-trailer system completing transportation works.

  7. Experiments with airplane brakes

    Science.gov (United States)

    Michael, Franz

    1931-01-01

    This report begins by examining the forces on the brake shoes. For the determination of the load distribution over the shoes it was assumed that the brake linings follow Hooke's law, are neatly fitted and bedded in by wear. The assumption of Hooke's law, that is, the proportionality between compression of the lining and the absorption of force, is fulfilled to a certain extent for the loading, as becomes apparent from the load tests described further on. But there is a material discrepancy at unloading. From the load distribution we merely defined the position of the normal force resultant, while for the rest, the effect of the distribution was disregarded in the comparison of the different shoe dispositions.

  8. Tether Deployer And Brake

    Science.gov (United States)

    Carroll, Joseph A.; Alexander, Charles M.

    1993-01-01

    Design concept promises speed, control, and reliability. Scheme for deploying tether provides for fast, free, and snagless payout and fast, dependable braking. Developed for small, expendable tethers in outer space, scheme also useful in laying transoceanic cables, deploying guidance wires to torpedoes and missiles, paying out rescue lines from ship to ship via rockets, deploying antenna wires, releasing communication and power cables to sonobuoys and expendable bathythermographs, and in reeling out lines from fishing rods.

  9. Brake assembly including torque monitor

    International Nuclear Information System (INIS)

    This patent describes a brake assembly for selectively braking rotation of an input shaft extending from a control rod drive having a longitudinal centerline axis, the shaft being rotatable for selectively inserting and withdrawing a control rod in a nuclear reactor vessel. It comprises a stationary base; an annular bearing mounted to the base; a brake mounted to the bearing; a backing plate mounted to the bearing; a first braking pad fixedly joined to the backing plate; a rotor disc fixedly connected to the input shaft and disposed adjacent to the first pad; a second braking pad disposed adjacent to the rotor disc; and means for selectively clamping the first and second pads against the rotor disc for braking the input shaft; means for torsionally restraining the brake including: a pin extending outwardly from the backing plate toward the base; and a spring extending from the base to the pin and generally perpendicular to the centerline axis; and means for monitoring the angle for monitoring braking torque capability of the brake

  10. Speciation of Sb in airborne particulate matter, vehicle brake linings, and brake pad wear residues

    Science.gov (United States)

    Varrica, D.; Bardelli, F.; Dongarrà, G.; Tamburo, E.

    2013-01-01

    Insights into the speciation of Sb in samples of brake linings, brake pad wear residues, road dust, and atmospheric particulate matter PM10 and PM2.5 were obtained combining several well established and advanced characterization techniques, such as scanning electron microscopy - energy dispersive spectrometry (SEM-EDS), inductively coupled plasma mass spectrometry (ICP-MS) and synchrotron radiation X-ray absorption spectroscopy (SR-XAS). The advantage of SR-XAS is that samples do not undergo any chemical treatment prior to measurements, thus excluding possible alterations. These analyses revealed that the samples of wheel rims dust, road dust, and atmospheric particulate matter are composed by an admixture of Sb(III) and Sb(V) in different relative abundances. Brake linings turned out to be composed by Sb(III) oxide (Sb2O3) and stibnite (Sb2S3). Stibnite was also detected in some of the particulate matter samples. The obtained data suggest that Sb2S3 during the brake abrasion process is easily decomposed forming more stable compounds such as antimony mixed oxidic forms. Sb redox speciation, in particular and well studied circumstances, may enhance the potential and selectivity of this element as a tracer of motor vehicle emissions in apportioning studies.

  11. 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...

  12. Pulsar braking: magnetodipole vs. wind

    CERN Document Server

    Tong, H

    2015-01-01

    Pulsars are good clocks in the universe. One fundamental question is that why they are good clocks? This is related to the braking mechanism of pulsars. Nowadays pulsar timing is done with unprecedented accuracy. More pulsars have braking indices measured. The period derivative of intermittent pulsars and magnetars can vary by a factor of several. However, during pulsar studies, the magnetic dipole braking in vacuum is still often assumed. It is shown that the fundamental assumption of magnetic dipole braking (vacuum condition) does not exist and it is not consistent with the observations. The physical torque must consider the presence of the pulsar magnetosphere. Among various efforts, the wind braking model can explain many observations of pulsars and magnetars in a unified way. It is also consistent with the up-to-date observations. It is time for a paradigm shift in pulsar studies: from magnetic dipole braking to wind braking. As one alternative to the magnetospheric model, the fallback disk model is also...

  13. Pulsar braking: magnetodipole vs. wind

    Science.gov (United States)

    Tong, Hao

    2016-01-01

    Pulsars are good clocks in the universe. One fundamental question is that why they are good clocks? This is related to the braking mechanism of pulsars. Nowadays pulsar timing is done with unprecedented accuracy. More pulsars have braking indices measured. The period derivative of intermittent pulsars and magnetars can vary by a factor of several. However, during pulsar studies, the magnetic dipole braking in vacuum is still often assumed. It is shown that the fundamental assumption of magnetic dipole braking (vacuum condition) does not exist and it is not consistent with the observations. The physical torque must consider the presence of the pulsar magnetosphere. Among various efforts, the wind braking model can explain many observations of pulsars and magnetars in a unified way. It is also consistent with the up-to-date observations. It is time for a paradigm shift in pulsar studies: from magnetic dipole braking to wind braking. As one alternative to the magnetospheric model, the fallback disk model is also discussed.

  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. 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...... using a scanning electron microscope.A brake pad is essentially a mixture of iron, carbon and binder. Combined techniques have been used, because of chemical reaction overlap, to determine how and at what temperature the binder decomposes, the coal and graphite combust and the iron oxidises.This work...

  16. 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...

  17. Weight reduction of a standard brake drum: A design approach

    OpenAIRE

    D. Rambabu; R. Gopinath; U. Senthil rajan; G. B. Bhaskar

    2014-01-01

    A Brake drum is specialized brake that uses the concept of friction to decelerate the vehicle speed. The deceleration is achieved by the assistance of the friction generated by a set of brake shoes or pad, when operator presses against a rotating brake drum. The material generally preferred for making the brake drum is grey cast iron or vermicular cast iron. The drum brake is highly efficient for hand brake and service brake applications. During the operation of drum brake excessive heating o...

  18. Post-outburst Observations of the Magnetically Active Pulsar J1846-0258: a new braking index, increased timing noise, and radiative recovery

    CERN Document Server

    Livingstone, Margaret A; Kaspi, Victoria M; Gavriil, Fotis P; Gotthelf, E V

    2010-01-01

    The ~800 yr-old pulsar J1846-0258 is a unique transition object between rotation-powered pulsars and magnetars: though behaving like a rotation-powered pulsar most of the time, in 2006 it exhibited a distinctly magnetar-like outburst accompanied by a large glitch. Here we present X-ray timing observations taken with the Rossi X-ray Timing Explorer over a 2.2-yr period after the X-ray outburst and glitch had recovered. We observe that the braking index of the pulsar, previously measured to be n=2.65+/-0.01, is now n=2.16+/-0.13, a decrease of 20+/-5%. We also note a persistent increase in the timing noise relative to the pre-outburst level. Despite the timing changes, a 2009 Chandra X-ray Observatory observation shows that the X-ray flux and spectrum of the pulsar and its wind nebula are consistent with the quiescent levels observed in 2000.

  19. Can Dark Matter explain the Braking Index of Neutron Stars?

    CERN Document Server

    Kouvaris, Chris

    2014-01-01

    We explore a new mechanism of slowing down the rotation of neutron stars via accretion of millicharged dark matter. We find that this mechanism yields pulsar braking indices that can be substantially smaller than the standard $n\\sim 3$ of the magnetic dipole radiation model for millicharged dark matter particles that are not excluded by existing experimental constraints thus accommodating existing observations.

  20. Can dark matter explain the braking index of neutron stars?

    DEFF Research Database (Denmark)

    Kouvaris, C.; Perez-Garcia, M. A.

    2014-01-01

    We explore a new mechanism of slowing down the rotation of neutron stars via accretion of millicharged dark matter. We find that this mechanism yields pulsar braking indices that can be substantially smaller than the standard n similar to 3 of the magnetic dipole radiation model for millicharged...... dark matter particles that are not excluded by existing experimental constraints thus accommodating existing observations....

  1. Hydraulic braking system for loads subjected to impacts and vibrations

    International Nuclear Information System (INIS)

    This invention concerns a hydraulic braking system for loads subjected to impacts and vibrations. These double acting telescopic type hydraulic braking systems possess significant drawbacks linked to possibly important hydraulic leaks due to (a) the use of many dynamic seals in such appliances and (b) the effects of the environment of the system on these seals, particularly when employed in nuclear power stations where the seals reach significant temperatures and are subjected to radiation. Under this invention a remedy is suggested to such drawbacks by integrating means to offset automatically the leaks and the accumulation of hydraulic fluid expansions, as well as facilities to show if such leaks have occurred

  2. What can the braking indices tell us about pulsars' nature?

    CERN Document Server

    Yue, Y L; Zhu, W W

    2006-01-01

    As a result of observational difficulties, braking indices of only six rotation-powered pulsars are obtained with certainty, all of which are remarkably smaller than the value ($n=3$) expected for pure magnetodipole radiation model. This is still a real fundamental question not being well answered after nearly forty years of the discovery of pulsar. The main problem is that we are shamefully not sure about the dominant mechanisms that result in pulsars' spin-down. Based on the previous works, the braking index is re-examined, with a conclusion of suggesting a constant gap potential drop for pulsars with magnetospheric activities. New constrains on model parameters from observed braking indices are presented.

  3. 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.

  4. RELIABILITY ANALYSIS OF CRANE BRAKE PARAMETERS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The high failure rate of crane brake results from improper choice of braking torque. The mathematical model of reliability for the crane brake parameters is introduced. Based on large amount of actual data the parameter reliabilities of 5~50 t general overhead travelling cranes are calculated,the probabilities that the braking torque is less than the static torque acting on the axle when the load moves down are obtained. Moreover,the ways to improve the reliability of brake parameters are discussed,the most reasonable values of braking safety coefficient are given.

  5. Braking index of isolated pulsars: open questions and ways forward

    CERN Document Server

    Hamil, Oliver

    2015-01-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate, the commonly accepted view is that it arises either through emission of magnetic dipole radiation (MDR) from a rotating magnetized body, through emission of a relativistic particle wind, or via higher order magnetic multipole or gravitational quadrupole radiation. The calculated energy loss by a rotating pulsar is model dependent and leads to the power law $\\dot{\\Omega}$ = -K $\\Omega^{\\rm n}$ where $n$ is called the braking index. The theoretical value for braking index is $n = 1, 3, 5$ for wind, MDR, quadrupole radiation respectively. The accepted view is that pulsar braking is strongly dominated by MDR. Highly precise observations of isolated pulsars yield braking index values in the range $1 < n < 2.8$ which are consistently less than the value pred...

  6. Evolution of the pulsar inclination angle in the wind braking model

    CERN Document Server

    Kou, F F; Wang, N

    2016-01-01

    In a plasma filled magnetosphere, in addition to providing a torque to brake down the pulsar, the magnetosphere will also generate a torque to align the pulsar magnetic and rotational axes. The evolution of pulsar inclination angle in the wind braking model is calculated. In the wind braking model, the oblique pulsar tends to align. The pulsar alignment will also affect the spin-down behavior. Braking index will increase firstly and then decrease as the pulsar evolving from the magneto-dipole radiation dominated case to the wind braking dominated case. Braking index may be larger than $3$ in the early time. And during the following long time, braking index will be always smaller than $3$. This can explain braking index observations of larger than $3$ and smaller than $3$. Besides, the pulsar will evolve downwards straightly to the death valley after pulsar death in the $P-\\dot{P}$ diagram. This may explain the observed maximum spinning period of pulsars. And the long-term evolution of pulsars in the wind brak...

  7. 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...

  8. BRAKING OF HIGH-SPEED PASSENGER TRAINS WITH REGARD TO THE OPERATION OF AN ELECTROMAGNETIC RAIL BRAKE

    Directory of Open Access Journals (Sweden)

    N. Je. Naumenko

    2009-03-01

    Full Text Available The research of the braking process of high-speed passenger train with the use of compressed-air, electropneumatic and electromagnetic track brakes is carried out. The dependences of braking distance on motion speed for vehicles equipped by block or disk brakes as well as for a case of electromagnetic track brakes used in addition to existing braking means.

  9. 49 CFR 238.231 - Brake system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Brake system. 238.231 Section 238.231... Equipment § 238.231 Brake system. Except as otherwise provided in this section, on or after September 9... train's primary brake system shall be capable of stopping the train with a service application from...

  10. Compact, Lightweight Servo-Controllable Brakes

    Science.gov (United States)

    Lovchik, Christopher S.; Townsend, William; Guertin, Jeffrey; Matsuoka, Yoky

    2010-01-01

    Compact, lightweight servo-controllable brakes capable of high torques are being developed for incorporation into robot joints. A brake of this type is based partly on the capstan effect of tension elements. In a brake of the type under development, a controllable intermediate state of torque is reached through on/off switching at a high frequency.

  11. Eddy current braking experiment using brake disc from aluminium series of A16061 and A17075

    International Nuclear Information System (INIS)

    The electromagnetic braking using eddy current was studied, focused on two series of aluminium as the brake disc which are A16061 and A17075. This paper presents the comparison for both series in a few varied parameters related to eddy current braking such as air-gap, number of turns and brake disc thickness. Optical tachometer has been used along with PULSE analyzer to capture the speed (rpm) and time (s). The findings shows that the smaller the air-gap, the larger of electromagnet turns and the thicker disc thickness is, will generate higher braking torque to stop the rotational motion of disc brake and give great performance for eddy current braking. Thos parameters that been evaluated also addressed a potential on expanding this knowledge to develop an electromagnetic braking system to replace the conventional braking system.

  12. 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...

  13. 49 CFR 570.55 - Hydraulic brake system.

    Science.gov (United States)

    2010-10-01

    ... 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 with hydraulic brake systems. (a) Brake system failure indicator. The hydraulic brake system failure...

  14. A Pulsar Eases Off the Brakes

    Science.gov (United States)

    Kohler, Susanna

    2015-10-01

    In 2006, pulsar PSR 18460258 unexpectedly launched into a series of energetic X-ray outbursts. Now a study has determined that this event may have permanently changed the behavior of this pulsar, raising questions about our understanding of how pulsars evolve.Between CategoriesA pulsar a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation can be powered by one of three mechanisms:Rotation-powered pulsars transform rotational energy into radiation, gradually slowing down in a predictable way.Accretion-powered pulsars convert the gravitational energy of accreting matter into radiation.Magnetars are powered by the decay of their extremely strong magnetic fields.Astronomical classification often results in one pesky object that doesnt follow the rules. In this case, that object is PSR 18460258, a young pulsar categorized as rotation-powered. But in 2006, PSR 18460258 suddenly emitted a series of short, hard X-ray bursts and underwent a flux increase behavior that is usually only exhibited by magnetars. After this outburst, it returned to normal, rotation-powered-pulsar behavior.Since the discovery of this event, scientists have been attempting to learn more about this strange pulsar that seems to straddle the line between rotation-powered pulsars and magnetars.Unprecedented DropOne way to examine whats going on with PSR 18460258 is to evaluate whats known as its braking index, a measure of how quickly the pulsars rotation slows down. For a rotation-powered pulsar, the braking index should be roughly constant. The pulsar then slows down according to a fixed power law, where the slower it rotates, the slower it slows down.In a recent study, Robert Archibald (McGill University) and collaborators report on 7 years worth of timing observations of PSR 18460258 after its odd magnetar-like outburst. They then compare these observations to 6.5 years of data from before the outburst. The team finds that the braking index for this bizarre

  15. Electromagnetic braking for Mars spacecraft

    Science.gov (United States)

    Holt, A. C.

    1986-01-01

    Aerobraking concepts are being studied to improve performance and cost effectiveness of propulsion systems for Mars landers and Mars interplanetary spacecraft. Access to megawatt power levels (nuclear power coupled to high-storage inductive or capacitive devices) on a manned Mars interplanetary spacecraft may make feasible electromagnetic braking and lift modulation techniques which were previously impractical. Using pulsed microwave and magnetic field technology, potential plasmadynamic braking and hydromagnetic lift modulation techniques have been identified. Entry corridor modulation to reduce loads and heating, to reduce vertical descent rates, and to expand horizontal and lateral landing ranges are possible benefits. In-depth studies are needed to identify specific design concepts for feasibility assessments. Standing wave/plasma sheath interaction techniques appear to be promising. The techniques may require some tailoring of spacecraft external structures and materials. In addition, rapid response guidance and control systems may require the use of structurally embedded sensors coupled to expert systems or to artificial intelligence systems.

  16. Falling Magnets and Electromagnetic Braking

    Science.gov (United States)

    Culbreath, Christopher; Palffy-Muhoray, Peter

    2009-03-01

    The slow fall of a rare earth magnet through a copper pipe is a striking example of electromagnetic braking; this remarkable phenomenon has been the subject of a number of scientific paper s [1, 2]. In a pipe having radius R and wall thickness D, the terminal velocity of the falling magnet is proportional to (R̂4)/D. It is interesting to ask what happens in the limit as D becomes very large. We report our experimental observations and theoretical predictions of the dependence of the terminal velocity on pipe radius R for large D. [1] Y. Levin, F.L. da Silveira, and F.B. Rizzato, ``Electromagnetic braking: A simple quantitative model''. American Journal of Physics, 74(9): p. 815-817 (2006). [2] J.A. Pelesko, M. Cesky, and S. Huertas, Lenz's law and dimensional analysis. American Journal of Physics, 3(1): p. 37-39. 2005.

  17. What brakes the Crab pulsar?

    Science.gov (United States)

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

    2016-03-01

    Context. 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. Aims: 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. Methods: 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. Results: From our analysis, we demonstrate that the power law index undergoes "instantaneous" changes at the time of observed jumps in rotational frequency (glitches). We find that the phase evolution of the Crab pulsar is dominated by a series of constant braking law episodes, with the braking index changing abruptly after each episode in the range of values between 2.1 and 2.6. Deviations from such a regular phase description behave as oscillations triggered by glitches and amount to fewer than 40 turns during the above period, in which the pulsar has made more than 2 × 1010 turns. Conclusions: Our analysis does not favor the explanation that glitches are connected to phenomena occurring in the interior of the pulsar. On the contrary, timing irregularities and changes in slow down rate seem to point to electromagnetic interaction of the pulsar with the surrounding environment.

  18. 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.

  19. Aerodynamic investigations of ventilated brake discs.

    OpenAIRE

    Parish, D.; MacManus, David G.

    2005-01-01

    The heat dissipation and performance of a ventilated brake disc strongly depends on the aerodynamic characteristics of the flow through the rotor passages. The aim of this investigation was to provide an improved understanding of ventilated brake rotor flow phenomena, with a view to improving heat dissipation, as well as providing a measurement data set for validation of computational fluid dynamics methods. The flow fields at the exit of four different brake rotor geometrie...

  20. CFD design analysis of ventilated disc brakes

    OpenAIRE

    Pulugundla, Gautam

    2008-01-01

    This thesis reports the numerical investigation of the automotive ventilated disc brake rotor. Disc brakes operate on the principle of friction by converting kinetic energy into heat energy. The main objective of a disc brake rotor is to store this heat energy and dissipate it as soon as possible. This work is carried out in a area where there is very limited understanding. Commercial CFD code FLUENT was used for carrying out the simulations with the rotor rotating in still ...

  1. 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…

  2. 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.

  3. 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.

  4. Landing and Braking of Airplanes

    Science.gov (United States)

    Breguet, Louis

    1929-01-01

    In the numerical examples, we have considered an airplane landing in calm air in a fixed direction after crossing the border (with its obstacles) at a height of 30 m. Its stopping point is at a distance D from the obstacle, comprising: a distance D(sub 1) in regular gliding flight; a distance D(sub 2) in levelling off; a distance D(sub 3) in taxying on the ground. The calculations enable us to make out the following table, which gives an idea of the improvements to be expected in the use of various possible methods of braking in the air and on the ground.

  5. Constraining the braking indices of magnetars

    Science.gov (United States)

    Gao, Z. F.; Li, X.-D.; Wang, N.; Yuan, J. P.; Wang, P.; Peng, Q. H.; Du, Y. J.

    2016-02-01

    Because of 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 the mean braking indices of eight magnetars with SNRs, and find that they cluster in the range of 1-42. Five magnetars have smaller mean braking indices of 1 wind-aided braking. The larger mean braking indices of n > 3 for the 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 1 3, within the updated magneto-thermal evolution models. Although the constrained range of the magnetars' braking indices is tentative, as a result of the uncertainties in the SNR ages due to distance uncertainties and the unknown conditions of the expanding shells, our method provides an effective way to constrain the magnetars' braking indices if the measurements of the SNR ages are reliable, which can be improved by future observations.

  6. 49 CFR 236.712 - Brake pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Brake pipe. 236.712 Section 236.712 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.712 Brake pipe. A...

  7. 14 CFR 27.921 - Rotor brake.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor brake. 27.921 Section 27.921... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.921 Rotor brake. If there is a means to control the rotation of the rotor drive system independently of the engine, any limitations...

  8. 14 CFR 29.921 - Rotor brake.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor brake. 29.921 Section 29.921... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.921 Rotor brake. If there is a means to control the rotation of the rotor drive system independently of the engine, any limitations...

  9. Operation peculiarities of airplane brake systems

    Directory of Open Access Journals (Sweden)

    В. Г. Докучаев

    1999-09-01

    Full Text Available Analyzed is the loading of airplane brake systems. Complex methods are proposed for investi­gation of highly loaded brake systems. The results of investigation of the influence of various factors on technical condition of friction units are given

  10. 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.

  11. New technical solutions of using rolling stock electrodynamical braking

    Directory of Open Access Journals (Sweden)

    Leonas Povilas LINGAITIS

    2009-01-01

    Full Text Available The paper considers some theoretical and practical problems associated with the use of traction motor are operating in the generator mode (in braking. Mathematical and graphical relationships of electrodynamic braking, taking into account the requirements raised to braking systems in rail transport are presented. The latter include discontinuity of braking process, braking force regulation, depending on the locomotive speed, mass, type of railway and other parameters. Schematic diagrams of the locomotive braking and ways of controlling the braking force by varying electric circuit parameters are presented. The authors suggested contact-free regulation method of braking resistor for controlling braking force in rheostatic braking, and resistor parameters regulate with pulse regulation mode by semiconductor devices, such as new electrical components for rolling stock – IGBT transistors operating in the key mode. Presenting energy savings power systems, which are using regenerative braking-returning energy and diesel engine or any form of hybrid traction vehicles systems, circuit diagrams, electrical parameters curves.

  12. 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...

  13. Marble Waste Using Produced of Automotive Brake Pad of Friction Coefficient Different Pad Brake Pads With Comprasion

    Directory of Open Access Journals (Sweden)

    Mustafa Timur

    2013-01-01

    Full Text Available Brake linings used in automotive disks are usually composed of various components. Expected properties from a brake lining are appropriate standard value of wear resist, friction coefficient. Brake lining extremely warms up during braking due to friction. The braking performance of brake lining changes and braking lining is subject to mechanical deformation due to excessive temperature. In this study, it is aimed to revaluate the waste of marble dust in marble processing in Turkey. For this purpose, marble wastes are grinded to produce marble dust. The brake lining, which has new formulation, is produced by using various additive materials. The friction performances of the brake pads produced were compared with those of other firms and the results were show in graphics. Therefore, the effect of marble dust on braking performance is investigated. It is observed that a favorable result in braking performance is obtained using of marble dust.

  14. Diesel Technology: Brakes. Teacher Edition [and] Student Edition.

    Science.gov (United States)

    Hilley, Robert; Scarberry, Terry; Kellum, Mary

    This document contains teacher and student materials for a course on brakes in the diesel technology curriculum. The course consists of 12 units organized in three sections. The three units of the introductory section cover: (1) brakes; (2) wheel bearings and seals; and (3) antilock brake systems. The second section, Hydraulic Brakes, contains the…

  15. Nonlinear Coupling Characteristics Analysis of Integrated System of Electromagnetic Brake and Frictional Brake of Car

    Directory of Open Access Journals (Sweden)

    Ren He

    2015-01-01

    Full Text Available Since theoretical guidance is lacking in the design and control of the integrated system of electromagnetic brake and frictional brake, this paper aims to solve this problem and explores the nonlinear coupling characteristics and dynamic characteristics of the integrated system of electromagnetic brake and frictional brake. This paper uses the power bond graph method to establish nonlinear coupling mathematical model of the integrated system of electromagnetic brake and frictional brake and conducts the contrastive analysis on the dynamic characteristics based on this mathematical model. Meanwhile, the accuracy of the nonlinear coupling mathematical model proposed above is verified on the hardware in the loop simulation platform, and nonlinear coupling characteristics of the integrated system are also analyzed through experiments.

  16. The influence of various pressures in pneumatic tyre on braking process of car with anti-lock braking system

    Directory of Open Access Journals (Sweden)

    Damian HADRYŚ

    2008-01-01

    Full Text Available In this article has been presented the influence of various pressures inpneumatic tyre of passenger car Fiat Panda 1.3 JTD with anti-lock braking system on chosen parameters of braking process: course of braking deceleration, maximum value of deceleration, braking distances.

  17. Screw-released roller brake

    Science.gov (United States)

    Vranish, John M. (Inventor)

    1999-01-01

    A screw-released roller brake including an input drive assembly, an output drive assembly, a plurality of locking sprags, a mechanical tripper nut for unlocking the sprags, and a casing therefor. The sprags consist of three dimensional (3-D) sprag members having pairs of contact surface regions which engage respective pairs of contact surface regions included in angular grooves or slots formed in the casing and the output drive assembly. The sprags operate to lock the output drive assembly to the casing to prevent rotation thereof in an idle mode of operation. In a drive mode of operation, the tripper is either self actuated or motor driven and is translated linearly up and down against a spline and at the limit of its travel rotates the sprags which unlock while coupling the input drive assembly to the output drive assembly so as to impart a turning motion thereto in either a clockwise or counterclockwise direction.

  18. An Intelligent Regenerative Braking Strategy for Electric Vehicles

    OpenAIRE

    Zhibin Song; Weimin Li; Guoqing Xu; Kun Xu

    2011-01-01

    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 ex...

  19. An Intelligent Regenerative Braking Strategy for Electric Vehicles

    OpenAIRE

    Guoqing Xu; Weimin Li; Kun Xu; Zhibin Song

    2011-01-01

    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 ex...

  20. Dynamics of braking vehicles: from Coulomb friction to anti-lock braking systems

    International Nuclear Information System (INIS)

    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 without sliding. The advantage of using an anti-lock braking system (ABS) is put in evidence, and a quantitative estimate of its efficiency is proposed and discussed

  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. Method and apparatus for wind turbine braking

    Science.gov (United States)

    Barbu, Corneliu; Teichmann, Ralph; Avagliano, Aaron; Kammer, Leonardo Cesar; Pierce, Kirk Gee; Pesetsky, David Samuel; Gauchel, Peter

    2009-02-10

    A method for braking a wind turbine including at least one rotor blade coupled to a rotor. The method includes selectively controlling an angle of pitch of the at least one rotor blade with respect to a wind direction based on a design parameter of a component of the wind turbine to facilitate reducing a force induced into the wind turbine component as a result of braking.

  3. 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...

  4. Topology Optimization in Automotive Brake Pedal Redesign

    Directory of Open Access Journals (Sweden)

    Mohd Nizam Sudin

    2014-03-01

    Full Text Available Nowadays, automotive industry is continuing to strive for light weight vehicle in improving fuel efficiency and emissions reduction. To produce a better performance car it is important to design vehicles with optimum weight. In order to reduce the weight of vehicle without sacrificing its integrity, this project aims to employ topology optimization technique to propose an optimal design of an automotive component in early phase of product development. In this project the material used for an existing brake pedal is unchanged as this study focuses on reducing weight of existing brake pedal without material substitution. The digital model of an existing brake pedal was generated using CATIA V5 solid modelling software. Topology optimization was performed by using Altair Optistruct software under linear static stress analysis. Finally, a new light weight design brake pedal is proposed. The result of the study shows that the weight of a new designed brake pedal was 22% less as compared to an existing brake pedal without sacrificing its performance requirement.

  5. Automated visual inspection of brake shoe wear

    Science.gov (United States)

    Lu, Shengfang; Liu, Zhen; Nan, Guo; Zhang, Guangjun

    2015-10-01

    With the rapid development of high-speed railway, the automated fault inspection is necessary to ensure train's operation safety. Visual technology is paid more attention in trouble detection and maintenance. For a linear CCD camera, Image alignment is the first step in fault detection. To increase the speed of image processing, an improved scale invariant feature transform (SIFT) method is presented. The image is divided into multiple levels of different resolution. Then, we do not stop to extract the feature from the lowest resolution to the highest level until we get sufficient SIFT key points. At that level, the image is registered and aligned quickly. In the stage of inspection, we devote our efforts to finding the trouble of brake shoe, which is one of the key components in brake system on electrical multiple units train (EMU). Its pre-warning on wear limitation is very important in fault detection. In this paper, we propose an automatic inspection approach to detect the fault of brake shoe. Firstly, we use multi-resolution pyramid template matching technology to fast locate the brake shoe. Then, we employ Hough transform to detect the circles of bolts in brake region. Due to the rigid characteristic of structure, we can identify whether the brake shoe has a fault. The experiments demonstrate that the way we propose has a good performance, and can meet the need of practical applications.

  6. 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.

  7. Geometric optimal design of a magneto-rheological brake considering different shapes for the brake envelope

    International Nuclear Information System (INIS)

    When designing a magneto-rheological brake (MRB), it is well known that the shape of the brake envelope significantly affects the performance characteristics of the brake. In this study, different shapes for the MR brake envelope, such as rectangular, polygonal or spline shape, are considered and the most suitable shape identified. MRBs with different envelope shapes are introduced followed by the derivation of the braking torque based on Bingham-plastic behavior of the magneto-rheological fluid (MRF). Optimization of the design of the MRB with different envelope shapes is then done. The optimization problem is to find the optimal value for the significant geometric dimensions of the MRB that can produce a certain required braking torque while the brake mass is minimized. A finite element analysis integrated with an optimization tool is employed to obtain optimal solutions for the MRBs. From the results, the most suitable shape for the brake envelope is identified and discussed with the reduction of mass. In addition, the results of the analysis are compared with the experimental results to verify the proposed optimal design characteristics. (paper)

  8. 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.

  9. Neutrons put the brakes on stress

    International Nuclear Information System (INIS)

    Don't you hate it when you're driving along, put your foot on the brake and feel that juddering feeling through the pedal? It happens when the disc brake rotors become distorted through normal use of the brakes. To the car manufacturing industry it's called runout, and is a multimillion dollar warranty problem each year. Not to mention a pain for drivers! Dr Maurice Ripley and Dr Oliver Kirstein from the Australian Nuclear Science and Technology Organisation (ANSTO) wanted to figure out whether runout is caused by residual stresses from the manufacturing process or by normal use of the brake, so they decided to test and compare a used and new brake disc. 'To picture what metal looks like at the atomic level, imagine spheres stacked evenly around each other in all three dimensions,' explained Kirstein. The spheres represent atoms in the metal and the structure is called a metallic lattice.' We're familiar with the idea that metal expands when it gets hot - the atoms get excited with the heat and have the energy to move further away from each other, so spaces between the atoms in the lattice get larger. 'When parts of the metal are heated up and cool down at different rates, you may end up with a distorted lattice with some parts expanded and others not,' explained Kirstein. 'This unevenness in the lattice creates residual stress.' While a bunch of methods were available to test the discs, Kirstein and Ripley picked neutrons from ANSTO's HIFAR (High Flux Australian Reactor) as their tool of choice. 'Neutrons allow us to look at the inside of the metal without damaging it,' said Kirstein. 'They can penetrate through the iron, so we were able to take measurements at a series of points at different depths through the brake disc.' Word around the car industry is that when residual stresses are relaxed through heating of the brake disc during use, the discs could potentially distort, causing the runout and that juddering feeling. But everyone was clueless as to what

  10. Weight reduction of a standard brake drum: A design approach

    Directory of Open Access Journals (Sweden)

    D. Rambabu

    2014-03-01

    Full Text Available A Brake drum is specialized brake that uses the concept of friction to decelerate the vehicle speed. The deceleration is achieved by the assistance of the friction generated by a set of brake shoes or pad, when operator presses against a rotating brake drum. The material generally preferred for making the brake drum is grey cast iron or vermicular cast iron. The drum brake is highly efficient for hand brake and service brake applications. During the operation of drum brake excessive heating of brake drum may occur. This excessive heating occurs due to repeated or frequent contact of the brake shoes against the drum. This causes the drum to crack, oversize, extreme wear, out of round drums and also leads to vibration which while braking will leads to reduced brake drum life and braking efficiency. The Un-laden weight of the vehicle will result in increased fuel consumption, reduced payload and ride handling characteristics. The objective of the paper is to improve the thermal characteristics by incorporating fins in the brake drum and to reduce the un-laden weight of the vehicle by changing the rib thickness, wall thickness and base flange thickness. The design is done by using 3D CAD Modelling software and Hexahedral finite element model prepared by using CAE pre-processing software and Stiffness analysis. Design iterations are carried out by using Linear/Non-linear Finite Element Solvers, Stress Displacement and Temperature is post-processed for design validation. Optimized design solution obtained based on the comparison study between the iteration with rib thickness 75 mm, star shaped removal and wall thickness 17 mm has been chosen. 1.8Kg of weight is being reduced from the brake drum including fins.   Keywords: Drum Brake, 3D CAD Modelling, Para Metric Matrix, Structural Analysis, Fins.

  11. 77 FR 51649 - Federal Motor Vehicle Safety Standards; Motorcycle Brake Systems

    Science.gov (United States)

    2012-08-24

    .... Wet Brake Test E. Heat Fade Test F. Parking Brake System Test G. Antilock Brake System (ABS.... Other ABS-Related Comments H. Partial Failure Test--Split Service Brake System I. Power-Assisted Braking..., Motorcycle Brake Systems, Notice of Proposed Rulemaking, 73 FR 54020 (Sept. 17, 2008) (hereinafter ``FMVSS...

  12. Brake force estimation for electromechanical vehicle brakes; Bremskraft-Rekonstruktion fuer elektromechanische Fahrzeugbremsen

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, R. [Continental Teves (Germany)

    1999-06-01

    Due to the increasing safety and comfort demands of the customer, the functionality of modern brake systems has grown continuously in the last years. However, implementation of the extended functionality in conventional brake hydraulics makes active electronic intervention necessary and therefore requires a lot of technical effort. In recent years the automotive supplier industry has started to develop brake systems which have electromechanical brake actuators generating the brake forces at the individual wheels. Electromechanically actuated wheel brakes need to be operated in a closed control loop. This paper introduces a new method to reconstruct the needed feedback value brake force from easy to measure signals. (orig.) [Deutsch] Aufgrund des gestiegenen Sicherheits- und Komfortbewusstseins der Fahrzeugkaeufer ist die Funktionsvielfalt moderner Bremssysteme in den letzten Jahren staendig gewachsen. Die Umsetzung der erweiterten Funktionalitaet mittels konventioneller Bremsenhydraulik ist jedoch durch den elektronischen, aktiven Eingriff sehr aufwendig. In den letzten Jahren hat daher die Automobilzulieferindustrie begonnen, Bremssysteme zu entwickeln, bei denen die Bremskraft an den einzelnen Raedern von elektromechanischen Bremsaktuatoren aufgebracht wird. Elektromechanisch betaetigte Radbremsen muessen im geschlossenen Regelkreis betrieben werden. Der vorliegende Beitrag, der im Rahmen einer Forschungskooperation zwischen Continental Teves und dem Institut fuer Automatisierungstechnik der TU Darmstadt entstand stellt ein Verfahren vor, mit dem die dafuer benoetigte Rueckfuehrungsgroesse `Bremskraft` aus einfach messbaren Signalen rekonstruiert werden kann. (orig.)

  13. 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.

  14. 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.

  15. 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...

  16. 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

  17. 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...

  18. 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...

  19. 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,...

  20. 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...

  1. Study on reduction method of brake squeal; Brake naki teigen shuho ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, T.; Okada, Y. [Aisin Seiki Co. Ltd., Aichi (Japan)

    1997-10-01

    The reduction of brake squeal is an important technological subject in terms of making vehicles quieter. In our research, we carried out a modal analysis from the caliper to the installation bracket during generating brake squeal to identify the places that influence the squeal. Based on this, we studied proposals to reduce the squeal, and have reduced the squeal noise at about 5 kHz as reported in this paper. 1 ref., 12 figs.

  2. Wear determination in braking systems by radioisotopes

    International Nuclear Information System (INIS)

    Friction and wear behaviour of friction couples has been tested applying loads and sliding speeds. The determination was carried out by direct measurements of the lining material and by surface activation of the opposite material with protons. The application limits of several braking materials could be determined and compared

  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. Electric disc brakes hold nuclear aircraft carriers

    International Nuclear Information System (INIS)

    Two nuclear-powered aircraft carriers, the U.S.S. Nimitz and the soon-to-be-completed U.S.S. Dwight D. Eisenhower, use electric disc brakes to stop and hold lines on warping and mooring capstans during docking maneuvers and mooring operations

  5. 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.

  6. Innovation of Electromagnetic Brake for Rail Vehicles

    Czech Academy of Sciences Publication Activity Database

    Ulrych, B.; Doležel, Ivo

    Opole : Technical University of Opole, 2005, s. 650-653. ISBN 83-88492-74-8. [International Symposium on Electrical Machines SME 2005 /41./. Opole-Jarnoltówek (PL), 14.06.2005-17.06.2005] Institutional research plan: CEZ:AV0Z20570509 Keywords : electromagnetic brake * electromagnetic field * numerical analysis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  7. 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.

  8. 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. PMID:20728647

  9. The Effect of Cashew to The Friction Performance Of Automotive Brake Linings

    OpenAIRE

    Timur, Mustafa; Kılıç, Halil; Sugözü, İlker

    2013-01-01

    Brake linings used in automotive disks are usually composed of various components. Expected properties from a brake lining are appropriate standart value of wear resist, friction coefficient and also economical value. Brake lining extremely warms up during braking due to friction. The braking performance of brake lining changes and braking lining is subject to mecanical deformation due to excessive temperature. In recent twenty years in consequence of fast development in automotive technology...

  10. 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...

  11. Experimental Study on A New Type of Air-cooled Brake Drum's Braking Performance%自助风冷型制动鼓制动性能试验研究

    Institute of Scientific and Technical Information of China (English)

    赵悟; 杜木伟; 刘晨敏; 沈建军; 于宥源

    2013-01-01

    The structure and cooling mechanisms of a new type of air-cooled brake drum are introduced. Contrast test of temperature rising, brake torque and rotation speed are conducted by the inertia brake tester JF122C between the new type of air-cooled brake drum and the original brake drum. Meanwhile the strength and stiffness of the holes-drilled new type one are analyzed. The result of the contrast test proves that, compared with the original, the average maximum temperature of the new type of air-cooled brake drum is reduced by about 15℃, its average brake torque doesn't change much, and the initial revolving speed and declining trend of every test are alike, the strength and stiffness degrade little, i.e the new type of brake drum greatly improves heat radiating performance of the brake system while maintaining braking safety.%介绍了新型风冷式制动鼓的结构和降温机理.针对新型风冷式制动鼓和原车制动鼓,在JF122C惯性制动试验台上进行了制动鼓温升、制动力矩和转速对比试验,并分析了钻小孔后的新型制动鼓的强度和刚度.试验结果表明,与原车制动鼓相比,新型风冷式制动鼓平均最高温度降低约15℃,平均制动力矩没有明显改变,制动初始转速及下降趋势一致,强度和刚度也未下降.即新型制动豉在保证制动安全性的前提下,较好地改善了制动系统的散热性能.

  12. 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.

  13. 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.

  14. 49 CFR 571.135 - Standard No. 135; Light vehicle brake systems.

    Science.gov (United States)

    2010-10-01

    ... the braking ratio of the vehicle. Antilock brake system or ABS means a portion of a service brake... neutral. (b) For an EV that is equipped with both ABS and RBS that is part of the service brake system, the ABS must control the RBS. S5.2. Parking brake system. Each vehicle shall be equipped with...

  15. 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.

  16. Friction characteristics of a brake friction material under different braking conditions

    International Nuclear Information System (INIS)

    Highlights: • The tribological behavior of the brake material is well depending on interfacial temperature and friction conditions. • The friction performance is influenced by the material heterogeneity and its anisotropy. • The friction performance depended on the nature, morphology and orientation of constituents. - Abstract: As the evaluation of the tribological properties of the brake lining material is important for the braking performance identification, a pad-on-disc friction and wear tests of a commercial brake pad material against cast iron disc were conducted under low, middle and severe conditions. Three experiments via (t1), (t2) and (t3) with different sliding speeds and nominal contact pressure were conducted. Tests were performed with the pad in periodic sliding contact for 30 cycles. The scanning electronic microscopic (SEM) analysis with energy dispersive X-ray (EDX) was used to characterize the rubbed surface. The results showed that during the run-in period, the coefficient of friction increases steadily. For the friction mechanism: (i) at lower conditions, a stable friction film was generated on the surface of the brake pad, providing excellent friction stability with less wear, (ii) at middle conditions, fibers were agglomerated and were not contributed more, and (iii) at higher conditions, contact plates were identified which were accommodated the speed and the load

  17. Braking Resistor Scheme for Transient Stability Improvement

    Directory of Open Access Journals (Sweden)

    Saeed Abazari

    2007-09-01

    Full Text Available One of the most important problems in power systems design is increasing the damping of the swing amplitude and also to increase the critical time in transient stability. One of the best techniques is to use resistor braking. However, their performance in power systems, duration of their activity and their place of installation are of great importance. In this paper by using of some of devices in power electronics and by precies modeling of the network and optimal controller is designed which leads as to our final objective. In fact resistor braking are effectively attract additive energy which is a result of disturbances and help us to improve the stability of overall system.

  18. Wind turbine trailing edge aerodynamic brakes

    Energy Technology Data Exchange (ETDEWEB)

    Migliore, P G [National Renewable Energy Lab., Golden, CO (United States); Miller, L S [Wichita State Univ., KS (United States). Dept. of Aerospace Engineering; Quandt, G A

    1995-04-01

    Five trailing-edge devices were investigated to determine their potential as wind-turbine aerodynamic brakes, and for power modulation and load alleviation. Several promising configurations were identified. A new device, called the spoiler-flap, appears to be the best alternative. It is a simple device that is effective at all angles of attack. It is not structurally intrusive, and it has the potential for small actuating loads. It is shown that simultaneous achievement of a low lift/drag ratio and high drag is the determinant of device effectiveness, and that these attributes must persist up to an angle of attack of 45{degree}. It is also argued that aerodynamic brakes must be designed for a wind speed of at least 45 m/s (100 mph).

  19. Modeling of a Hydraulic Braking System

    OpenAIRE

    Lundin, Christopher

    2015-01-01

    The objective of this thesis is to derive an analytical model representing a reduced form of a mine hoist hydraulic braking system. Based primarily on fluid mechanical and mechanical physical modeling, along with a number of simplifying assumptions, the analytical model will be derived and expressed in the form of a system of differential equations including a set of static functions. The obtained model will be suitable for basic simulation and analysis of system dynamics, with the aim to cap...

  20. An Intelligent Auxiliary Vacuum Brake System

    OpenAIRE

    Tong, Chia-Chang; Lin, Jhih-Yu; Li, Shih-Fan; Li, Jiun-Yi

    2009-01-01

    The purpose of this paper focuses on designing an intelligent, compact, reliable, and robust auxiliary vacuum brake system (VBS) with Kalman filter and self-diagnosis scheme. All of the circuit elements in the designed system are integrated into one programmable system-on-chip (PSoC) with entire computational algorithms implemented by software. In this system, three main goals are achieved: (a) Kalman filter and hysteresis controller algorithms are employed within PSoC chip by software to sur...

  1. Bernoulli effect at free revolving flow braking

    OpenAIRE

    Budarin, V. A.

    2013-01-01

    In this research paper, analytical equations for the calculation of radial flow due to the braking on the flat surface plane of revolving flow were obtained. The calculation method is based on the use of pressure force balance equation, viscid friction and inertia. Three motion equations for incompressible, polytropic and isothermal flow were obtained, the type of a cumulative curve for the incompressible flow has been shown. Possibility of the use of radial flow for the compression of water ...

  2. Braking Resistor Scheme for Transient Stability Improvement

    OpenAIRE

    Saeed Abazari

    2007-01-01

    One of the most important problems in power systems design is increasing the damping of the swing amplitude and also to increase the critical time in transient stability. One of the best techniques is to use resistor braking. However, their performance in power systems, duration of their activity and their place of installation are of great importance. In this paper by using of some of devices in power electronics and by precies modeling of the network and optimal controller is designed which...

  3. Failure analysis in locomotive Bogie Brake-Hanger

    Directory of Open Access Journals (Sweden)

    NAVNEET SINGH1

    2012-05-01

    Full Text Available Breakage of brake riggings in WAP7 locomotives has been a matter of concern since 2004, almost afterits commencement of manufacturing, which is having same bogie design as that in WAG9 locomotives. Both ofthese bogies are having TBU/PBU assembly for brakes, but breakage of brake hangers in WAG9 locomotivesare unheard off. Both the inner as well as outer hangers are breaking. However, the cases of breakage of innerhangers towards bogie frame are much more with 80% of the total failures. This paper deliberates to understandthe various failures in locomotive Bogie Brake-Hanger and on root cause analysis for the failure of Brakehanger. In this paper we analyze the characteristics of brake hanger using FEA software.The goal of the project is to develop a high-speed train system capable of reaching the maximum speedand to secure its key technologies, one of which is the braking technology.

  4. 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.

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

    CERN Document Server

    Chen, Wen-Cong

    2015-01-01

    Recent timing observation reported that the radio pulsar PSR J1734 - 3333 with a rotating period $P=1.17~\\rm s$ is slowing down with a period derivative $\\dot{P}=2.28\\times 10^{-12}\\rm s\\,s^{-1}$. Its derived braking index $n=0.9 \\pm 0.2$ 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 disk 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 fallback disk is $2 \\times 10^{17} \\rm g\\...

  6. High braking index pulsar PSR J1640-4631: low-mass neutron star with a large inclination angle?

    CERN Document Server

    Chen, Wen-Cong

    2016-01-01

    Recent timing observation constrained the braking index of the X-ray pulsar PSR J1640-4631 to be $n=3.15\\pm0.03$, which is the highest value of all pulsars with measured braking indices so far. In this Letter, we investigate whether pulsar braking by combined between the magnetic dipole emission and the gravitational radiation might have a braking index greater than three. For conventional neutron star and low mass quark star candidates, the inferred ellipticities derived by the observed braking index are obviously much larger than the theoretical estimated maximum value. If PSR J1640-4631 is a low-mass neutron star with a mass of $0.1~ \\rm M_{\\odot}$, the inferred ellipticity can be approximately equal to the theoretical estimated maximum value. Because of the radio-quiet nature of this source, we employ the vacuum gap model developed by Ruderman and Sutherland to constrain the inclination angle to be $87.2-90^{\\circ}$. Based on this, we propose that a low-mass neutron star with a large inclination angle can...

  7. The Friction of Vehicle Brake Tandem Master Cylinder

    Science.gov (United States)

    Kao, M. J.; Chang, H.; Tsung, T. T.; Lin, H. M.

    2006-10-01

    The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications.

  8. Low-impact friction materials for brake pads

    OpenAIRE

    Bonfanti, Andrea

    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...

  9. The Friction of Vehicle Brake Tandem Master Cylinder

    International Nuclear Information System (INIS)

    The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications

  10. Comparative Frictional Analysis of Automobile Drum and Disc Brakes

    OpenAIRE

    H.P. Khairnar; V.M. Phalle; S. S. Mantha

    2016-01-01

    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 hav...

  11. A Model Predictive Control Allocation Approach to Hybrid Braking of Electric Vehicles

    OpenAIRE

    Satzger, Clemens; Pinto de Castro, Ricardo; Buente, Tilman

    2014-01-01

    With the recent emergence of electric drivetrains, a faster and energy efficient braking actuator - the electric motor - has become available to complement the operation of the traditional friction brakes. The decision on how to split the braking torque among the friction brake and the electric motor is one of the main issues of such hybrid braking systems. With this challenge in mind, a new model predictive control allocation (MPCA) approach for hybrid braking is proposed. In comparison to s...

  12. 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, ...

  13. Evolving into Magnetars from Normal Pulsars with a Low Braking Index

    Institute of Scientific and Technical Information of China (English)

    CHEN Wen-Cong

    2009-01-01

    Anomalous x-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are believed to be candidates for magnetars, and they are powered by the decay of ultra-strong magnetic fields of > 1014 G. From the modified spin-down relation of pulsars P (x) p2-n, we find that the Vela pulsar would evolve into the classes of magnetars under some assumptions that pulsars lose their rotational energy only by magnetic dipole radiation and the braking index is a constant. Our rough calculation indicates that only pulsars with n ~ 1.3 - 1.6 can evolve into magnetars.Pulsars like Vela with a low braking index may be the progenitors of AXPs and SGRs. Regarding the mechanism evolved into magnetars, we suggest that pulsars' surface magnetic field component may be increased by frequent glitches.

  14. 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.

  15. 49 CFR 570.5 - Service brake system.

    Science.gov (United States)

    2010-10-01

    ...) Friction materials. On each brake the thickness of the lining or pad shall not be less than one thirty... CFR 571.105, on every new passenger car manufactured on or after January 1, 1968, and on other types... from loose material, oil, or grease. The service brakes shall be applied at a vehicle speed of 20...

  16. 49 CFR 570.59 - Service brake system.

    Science.gov (United States)

    2010-10-01

    ...) Friction materials. On each brake, the thickness of the lining or pad shall not be less than one thirty-second of an inch over the fastener, or one-sixteenth of an inch over the brake shoe on bonded linings or... percent grade), dry, smooth, hard-surfaced road that is free from loose material, oil or grease....

  17. Braking index of isolated uniformly rotating magnetized pulsars

    CERN Document Server

    Hamil, Oliver; Urbanec, Martin; Urbancova, Gabriela

    2015-01-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate in detail, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. 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 consi...

  18. Design of haptic master featuring small-sized MR brakes

    Science.gov (United States)

    Gang, Han Gyeol; Choi, Seung-Bok; Sohn, Jung Woo

    2016-04-01

    In this work, a new type of haptic master featuring small-sized MR brake is proposed and its performances are evaluated. The proposed haptic master consists of base frame, stick grip and small-sized four MR brakes for 3-DOF rotational motion and 1-DOF gripper motion. To obtain large braking torque under limited small size of MR brake, dual tapered shape inner magnetic core is proposed and its performance is evaluated via both numerical estimation and experimental test. After design and implementation of control algorithm, it has been demonstrated through experiment that the proposed actuator has good performances on tracking control of desired torques. Then, a new haptic master device is designed and constructed by adopting the proposed MR brakes and light weight frame structures. It is verified that the proposed haptic master device is effective for the real application in the field.

  19. 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.

  20. 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.

  1. Radial brake assembly for a control rod drive

    International Nuclear Information System (INIS)

    This patent describes a brake assembly for a control rod drive for selectively preventing travel of a control rod in a nuclear reactor vessel. It comprises a shaft having a longitudinal centerline axis; means for selectively rotating the shaft in a first direction and in a second direction, opposite to the first direction; a stationary housing having a central aperture receiving the shaft; a frame fixedly joined to the housing and having a guide hole; a rotor disc fixedly connected to the shaft for rotation therewith and having at least one rotor tooth extending radially outwardly from a perimeter thereof, the rotor tooth having a locking surface and an inclined surface extending therefrom in a circumferential direction; a brake member disposed adjacent to the rotor disc perimeter and including a base, at least one braking tooth having a locking surface extending therefrom in a circumferential direction, and a plunger extending radially outwardly from the base and slidably joined to the frame through the guide hole; the rotor tooth and the braking tooth being complementary to each other; and means for selectively positioning the brake member in a deployed position abutting the rotor disc perimeter for allowing the braking tooth locking surface to contact the rotor tooth locking surface for preventing rotation of the shaft in the first direction, and in a retracted position spaced radially away from the rotor disc for allowing the rotor disc and the shaft to rotate without restraint from the brake member, the positioning means including a tubular solenoid fixedly joined to the frame and having a central bore disposed around the brake member plunger and effective for sliding the brake member plunger relative to the frame for positioning the brake member in the deployed and retracted positions

  2. 49 CFR 236.554 - Rate of pressure reduction; equalizing reservoir or brake pipe.

    Science.gov (United States)

    2010-10-01

    ... or brake pipe. 236.554 Section 236.554 Transportation Other Regulations Relating to Transportation...; Locomotives § 236.554 Rate of pressure reduction; equalizing reservoir or brake pipe. The equalizing-reservoir pressure or brake-pipe pressure reduction during an automatic brake application shall be at a rate not...

  3. Optimal design of a disc-type MR brake for middle-sized motorcycle

    Science.gov (United States)

    Nguyen, Quoc-Hung; Jeon, Juncheol; Choi, Seung-Bok

    2011-03-01

    This research work focuses on optimal design of a disc-type magneto-rheological (MR) brake that can replace a conventional hydraulic brake (CHB) of middle-sized motorcycles. Firstly, a MR brake configuration is proposed considering the available space and the simplicity to replace a CHB by the proposed MR brake. An optimal design of the proposed MR brake is then performed considering the required braking torque, operating temperature, mass and size of the brake. In order to perform the optimization of the brake, the braking torque of the brake is analyzed based on Herschel-Bulkley rheological model of MR fluid. The constrain on operating temperature of the MR brake is determined by considering the steady temperature of the brake when the motorcycle is cruising and the temperature increase during a braking process. An optimization procedure based on finite element analysis integrated with an optimization tool is employed to obtain optimal geometric dimensions of the MR brake. Optimal solution of the MR brake is then presented and simulated performance of the optimized brake is shown with remarkable discussions.

  4. 49 CFR 571.121 - Standard No. 121; Air brake systems.

    Science.gov (United States)

    2010-10-01

    ... brakes. Antilock brake system or ABS means a portion of a service brake system that automatically... reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the material may be inspected at... control lines and reservoirs that minimizes damage in field operations. Air brake system means a...

  5. 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.

  6. Finite element analysis of advanced bicycle precision brake disk forming technology

    Directory of Open Access Journals (Sweden)

    Chen Dyi-Cheng

    2015-01-01

    Full Text Available In recent years, the bicycle has become an environmentally friendly transportation. The bicycle can be divided into mountain bicycle and highway bicycle. Safe driving is the prior consideration. The bicycle braking system can be divided into oil pressure disk brakes and mechanical disk brakes. The brake disk system is one indispensable component of the safe system. In accordance to overall weight consideration of the bike, the brake disk should also focus on the lightweight design. This paper discussed an innovative brake disk forming technology for 6061 aluminum alloy by the rigid-plastic finite element analysis. The simulation parameters include geometric shapes of the brake disk and mold, die temperature, and friction factors. The stress and strain in forming, brake deformation and vibration modal analysis of brake disk in riding were studied. The paper is expected to offer some precision bicycle brake disk manufacture knowledge for industry.

  7. Residual stresses in a cast iron automotive brake disc rotor

    International Nuclear Information System (INIS)

    Runout, and consequent juddering and pulsation through the brake pedal, is a multi-million dollar per year warranty problem for car manufacturers. There is some suspicion that the runout can be caused by relaxation of residual casting stresses when the disc is overheated during severe-braking episodes. We report here neutron-diffraction measurements of the levels and distribution of residual strains in a used cast iron brake disc rotor. The difficulties of measuring stresses in grey cast iron are outlined and three-dimensional residual-strain distributions are presented and their possible effects discussed

  8. Retardation-controlled safety brake at the test site

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, A.; Schroeder, R.; Sondermann, W.

    1989-02-01

    A double-drum winding installation is thought to require a retardation-controlled safety brake. The investigations needed for the design acceptance of such a braking installation have so far only been possible on an actual winding installation. This has not ruled out that the commissioning procedure of the whole installation could be delayed or endangered. The use of a simulator developed by the WBK Rope Testing Station, which replicates the behaviour of braked masses in the winding installation, made it possible for the first time to transfer a major part of the necessary investigations to the test site.

  9. 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.

  10. Gravitational waves from pulsars with measured braking index

    CERN Document Server

    de Araujo, Jose C N; Costa, Cesar A

    2016-01-01

    We study the putative emission of gravitational waves (GWs) in particular for pulsars with measured braking index. We show that the appropriate combination of both GW emission and magnetic dipole brakes can naturally explain the measured braking index, when the surface magnetic field and the angle between the magnetic dipole and rotation axes are time dependent. Then we discuss the detectability of these very pulsars by aLIGO and the Einstein Telescope. We call attention to the realistic possibility that aLIGO can detect the GWs generated by at least some of these pulsars, such as Vela, for example.

  11. Cycling and wind: does sidewind brake?

    International Nuclear Information System (INIS)

    It is well established that the presence of wind is crucial for the practice of numerous outdoor sports. Among them, the case of cycling competition is especially important because the speeds that are developed are perfectly comparable with moderate or strong winds, giving rise to great variability in race times. Conversely, the sidewind seems to behave as neutral in the race, and nevertheless all the cyclists know the difficulties that it causes. In this brief paper we show that the sidewind also produces an appreciable braking as a consequence of the quadratic dependence of the aerodynamic drag force on the air speed. Our work presents an interesting problem of mechanics and physics of fluids, which may be suitable as a task for intermediate level students in university courses

  12. 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

  13. 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

  14. 49 CFR 229.57 - Foundation brake gear.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.57... to the wheel to prevent localized thermal stress in the edge of the rim or the flange....

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. Experimental investigations for uncertainty quantification in brake squeal analysis

    Science.gov (United States)

    Renault, A.; Massa, F.; Lallemand, B.; Tison, T.

    2016-04-01

    The aim of this paper is to improve the correlation between the experimental and the numerical prediction of unstable frequencies for automotive brake systems considering uncertainty. First, an experimental quantification of uncertainty and a discussion analysing the contributions of uncertainty to a numerical squeal simulation are proposed. Frequency and transient simulations are performed considering nominal values of model parameters, determined experimentally. The obtained results are compared with those derived from experimental tests to highlight the limitation of deterministic simulations. The effects of the different kinds of uncertainty detected in working conditions of brake system, the pad boundary condition, the brake system material properties and the pad surface topography are discussed by defining different unstable mode classes. Finally, a correlation between experimental and numerical results considering uncertainty is successfully proposed for an industrial brake system. Results from the different comparisons reveal also a major influence of the pad topography and consequently the contact distribution.

  1. 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...

  2. 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 longterm vision and specific guidance on managing habitats for the resources of concern...

  3. Mathews Brake National Wildlife Refuge [Land Status Map

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This map was produced by the Division of Realty to depict landownership at Mathews Brake National Wildlife Refuge. It was generated from rectified aerial...

  4. Braking Index of Isolated Pulsars II: A novel two-dipole model of pulsar magnetism

    CERN Document Server

    Hamil, Oliver Q; Stone, Jirina R

    2016-01-01

    The magnetic dipole radiation (MDR) model is currently the best approach we have to explain pulsar radiation. However a most characteristic parameter of the observed radiation, the braking index n$_{\\rm obs}$ shows deviations for all the eight best studied isolated pulsars, from the simple model prediction n$_{\\rm dip}$ = 3. The index depends upon the rotational frequency and its first and second time derivatives, but also on the assumption of that the magnetic dipole moment and inclination angle, and the moment of inertia of the pulsar are constant in time. In a recent paper [Phys. Rev. D 91, 063007 (2015)] we showed conclusively that changes in the moment of inertia with frequency alone, cannot explain the observed braking indices. Possible observational evidence for the magnetic dipole moment migrating away from the rotational axis at a rate $\\dot\\alpha$ $\\sim$ 0.6$^{\\circ}$ per 100 years over the life time of the Crab pulsar has been recently suggested by Lyne et al. In this paper, we explore the MDR mode...

  5. Stability analysis and μ-synthesis control of brake systems

    OpenAIRE

    Lignon, Sylvain; Sinou, Jean-Jacques; Jezequel, Louis

    2006-01-01

    The concept of friction-induced brake vibrations, commonly known as judder, is investigated. Judder vibration is based on the class of geometrically induced or kinematic constraint instability. After presenting the modal coupling mechanism and the associated dynamic model, a stability analysis as well as a sensitivity analysis have been conducted in order to identify physical parameters for a brake design avoiding friction-induced judder instability. Next, in order to reduce the size of the i...

  6. Stability analysis and \\mu-synthesis control of brake systems

    OpenAIRE

    Lignon, Sylvain; Sinou, Jean-Jacques; Jezequel, Louis

    2008-01-01

    The concept of friction-induced brake vibrations, commonly known as judder, is investigated. Judder vibration is based on the class of geometrically induced or kinematic constraint instability. After presenting the modal coupling mechanism and the associated dynamic model, a stability analysis as well as a sensitivity analysis have been conducted in order to identify physical parameters for a brake design avoiding friction-induced judder instability. Next, in order to reduce the size of the i...

  7. 49 CFR 393.55 - Antilock brake systems.

    Science.gov (United States)

    2010-10-01

    ... Motor Vehicle Safety Standard (FMVSS) No. 105 (49 CFR 571.105, S5.5). (b) ABS malfunction indicators for... with an antilock brake system that meets the requirements of FMVSS No. 121 (49 CFR 571.121, S5.1.6.1(b... equipped with an antilock brake system that meets the requirements of FMVSS No. 121 (49 CFR 571.121,...

  8. 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.

  9. OPTIMAL EMERGENCY VEHICLE BRAKING CONTROL BASED ON DYNAMIC FRICTION MODEL

    OpenAIRE

    Olmos, L.; L. Álvarez-Icaza

    2005-01-01

    A dynamic friction model for the tire-road interface is used in an optimal control scheme for emergency braking of vehicles. The controller sets a target relative velocity curve that the vehicle must track in order to achieve braking in minimum 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.

  10. 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.

  11. 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.

  12. Radiation

    International Nuclear Information System (INIS)

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  13. Predict optimize the friction characteristics of brake pads; Brake pad no masatsu tokusei no yosoku to saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Saotome, H. [Nissin Kogyo Co., Tokyo (Japan); Kato, T. [The University of Tokyo, Tokyo (Japan)

    1997-10-01

    The effect of the friction and the wear properties of brake pads were experimentally studied using a test rig of scale of 1/10 of the system used in a commercial car. The experimental data were investigated by the Multiple Regression Analysis and the Neural Network, and the effects of volume % of components on the friction and the wear properties were predicted. In addition the components of brake pads are optimized by Genetic Algorithms. 8 refs., 9 figs., 4 tabs.

  14. Thermal measurement of brake pad lining surfaces during the braking process

    Science.gov (United States)

    Piątkowski, Tadeusz; Polakowski, Henryk; Kastek, Mariusz; Baranowski, Pawel; Damaziak, Krzysztof; Małachowski, Jerzy; Mazurkiewicz, Łukasz

    2012-06-01

    This paper presents the test campaign concept and definition and the analysis of the recorded measurements. One of the most important systems in cars and trucks are brakes. The braking temperature on a lining surface can rise above 500°C. This shows how linings requirements are so strict and, what is more, continuously rising. Besides experimental tests, very supportive method for investigating processes which occur on the brake pad linings are numerical analyses. Experimental tests were conducted on the test machine called IL-68. The main component of IL-68 is so called frictional unit, which consists of: rotational head, which convey a shaft torque and where counter samples are placed and translational head, where samples of coatings are placed and pressed against counter samples. Due to the high rotational speeds and thus the rapid changes in temperature field, the infrared camera was used for testing. The paper presents results of analysis registered thermograms during the tests with different conditions. Furthermore, based on this testing machine, the numerical model was developed. In order to avoid resource demanding analyses only the frictional unit (described above) was taken into consideration. Firstly the geometrical model was performed thanks to CAD techniques, which in the next stage was a base for developing the finite element model. Material properties and boundary conditions exactly correspond to experimental tests. Computations were performed using a dynamic LS-Dyna code where heat generation was estimated assuming full (100%) conversion of mechanical work done by friction forces. Paper presents the results of dynamic thermomechanical analysis too and these results were compared with laboratory tests.

  15. Characteristics of DC electrical braking method of the gas circulator to limit the temperature rise at the heat transfer pipes in the HTTR

    International Nuclear Information System (INIS)

    In the safety evaluation of a High Temperature Engineering Test Reactor (HTTR), it must be confirmed that the core has no chance to be damaged and the barrier against the FP release is designed properly not to be affecting the influence of radiation around the reactor site. Especially the maximum temperature of the reactor pressure boundary such as the heat transfer pipes of pressurized water cooler (PWC) must not exceed the permissible values under an anticipated accident such as pipe of rupture in PWC. A requirement for the gas circulator which circulates helium gas in the primary cooling line and the secondary cooling line, is to be braked within 10 seconds by an electrical braking method after the HTTR reactor has scrammed under the accident in PWC. The reason is that the temperature rise of the heat transfer pipe at PWC has to be suppressed when the gas circulator has stopped, the revolution of the gas circulator decreases like the free coast down so that it takes about 90 seconds to be zero and the temperature rise of the pipe in the PWC exceeds the permissible value. By braking within 10 secs., the temperature of the pipe in the PWC reaches about 368 deg. C, less than the permissible value. Using a simplified equivalent circuit of an induction motor, braking time analysis was performed with obtained electrical resistance and inductance. The obtained braking time is about 10 secs., showing close agreement with analysis values. (author)

  16. Intelligently Controllable Walker with Magnetorheological Fluid Brake

    Science.gov (United States)

    Kikuchi, Takehito; Tanida, Sosuke; Tanaka, Toshimasa; Kobayashi, Keigo; Mitobe, Kazuhisa

    Caster walkers are supporting frames with casters and wheels. These tools are regularly utilized as life support tools or walking rehabilitation tools in hospitals, nursing homes and individual residences. Users of the walkers can easily move it thanks to its wheels and casters. However falling accidents often happen when it moves without users. The falling accident is very serious problem and one of leading causes of secondary injuries. In the other case, it is hard to move to desired directions if users have imbalance in their motor functions or sensory functions, e.g., hemiplegic patients. To improve safeness and operability of the walkers, we installed compact MR fluid brakes on the wheels and controlled walking speed and direction of the walker. We named this intelligently controllable walker, “i-Walker” and discussed on the control methods and experimental results in this paper. Preliminary trials for direction control of the first-generation of the i-Walker (i-Walker1) are presented. On the basis of the results, we improved the control method and hardware of the i-Walker1, and developed the second-generation (i-Walker2). System description and experimental results of the i-Walker2 are also described. The i-Walker2 has better operability and lower energy consumption than that of the i-Walker1. The line-tracing controller of the i-Walker2 well controls human motions during walking experiments on the target straight line.

  17. 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.

  18. Rotational evolution of the Crab pulsar in the wind braking model

    CERN Document Server

    Kou, F F

    2015-01-01

    The pulsar wind model is updated by considering the effect of particle density and pulsar death. It can describe both the short term and long term rotational evolution of pulsars consistently. It is applied to model the rotational evolution of the Crab pulsar. The pulsar is spun down by a combination of magnetic dipole radiation and particle wind. The parameters of the Crab pulsar, including magnetic field, inclination angle, and particle density are calculated. The particle density in acceleration region is about 10^3 times the Goldreich-Julian charge density. The lower braking index between glitches is due to a larger particle density. This may be glitch induced magnetospheric activities in normal pulsars. Evolution of braking index and the Crab pulsar in P-Pdot diagram are calculated. The Crab pulsar will evolve from magnetic dipole radiation dominated case towards particle wind dominated case. Considering the effect of pulsar "death", the Crab pulsar (and other normal pulsars) will not evolve to the clust...

  19. Optimal design of an automotive magnetorheological brake considering geometric dimensions and zero-field friction heat

    International Nuclear Information System (INIS)

    This paper presents an optimal design of a magnetorheological (MR) brake for a middle-sized passenger car which can replace a conventional hydraulic disc-type brake. In the optimization, the required braking torque, the temperature due to zero-field friction of MR fluid, the mass of the brake system and all significant geometric dimensions are considered. After describing the configuration, the braking torque of the proposed MR brake is derived on the basis of the field-dependent Bingham and Herschel–Bulkley rheological model of the MR fluid. The optimal design of the MR brake is then analyzed taking into account available space, mass, braking torque and steady heat generated by zero-field friction torque of the MR brake. The optimization procedure based on the finite element analysis integrated with an optimization tool is proposed to obtain optimal geometric dimensions of the MR brake. Based on the proposed procedure, optimal solutions of single and multiple disc-type MR brakes featuring different types of MR fluid are achieved. From the results, the most effective MR brake for the middle-sized passenger car is identified and some discussions on the performance improvement of the optimized MR brake are described

  20. The Distribution of Secondary Masses in Post-Common Envelope Binaries: A Potential Test of Disrupted Magnetic Braking

    CERN Document Server

    Politano, M; Politano, Michael; Weiler, Kevin P.

    2006-01-01

    The distribution of secondary star masses in present-day post-common envelope binaries (PCEBs) is calculated using four different models for angular momentum loss (AML) during the post-CE phase: only gravitational radiation (GR), GR + disrupted magnetic braking (DMB), GR + reduced MB, and GR + intermediate MB. For the DMB model, we find that the number of PCEBs decreases abruptly by 38% once MB begins to operate for non-fully convective secondaries. We do not find a similar feature in the distributions calculated using any of the other three AML models in which MB is not disrupted. This percentage decrease in the number of present-day PCEBs predicted using the DMB model is easily large enough so that an observed distribution of secondary masses or even spectral types in PCEBs can provide an important test of whether magnetic braking is indeed substantially reduced in secondary stars that are fully convective. We discuss briefly the feasibility of such observations.

  1. Prosthetic leg powered by MR brake and SMA wires

    Science.gov (United States)

    Nguyen, The; Munguia, Vicente; Calderon, Jose

    2014-04-01

    Current knee designs for prosthetic legs rely on electric motors for both moving and stationary states. The electric motors draw an especially high level of current to sustain a fixed position. The advantage of using magnetorheological (MR) fluid is that it requires less current and can have a variable braking torque. Besides, the proposed prosthetic leg is actuated by NiTinol wire, a popular shape memory alloy (SMA). The incorporation of NiTinol gives the leg more realistic weight distribution with appropriate arrangement of the batteries and wires. The prosthesis in this research was designed with MR brake as stopping component and SMA wire network as actuating component at the knee. The MR brake was designed with novel non-circular shape for the rotor that improved the braking torque while minimizing the power consumption. The design also helped simplify the control of braking process. The SMA wire network was design so that the knee motion was actively rotated in both directions. The SMA wires were arranged and played very similar role as the leg's muscles. The study started with the overall solid design of the knee including both MR and SMA parts. Theoretical models were derived and programmed in Simulink for both components. The simulation was capable of predicting the power required for moving the leg or hold it in a fixed position for a certain amount of time. Subsequently, the design was prototyped and tested to validate the theoretical prediction. The theoretical models were updated accordingly to correlate with the experimental data.

  2. Optimal design of a magneto-rheological brake absorber for torsional vibration control

    International Nuclear Information System (INIS)

    This research presents an optimal design of a magneto-rheological (MR) brake absorber for torsional vibration control of a rotating shaft. Firstly, the configuration of an MR brake absorber for torsional vibration control of a rotating shaft system is proposed. Then, the braking torque of the MR brake is derived based on the Bingham plastic model of the MR fluid. By assuming that the behaviour of the MR brake absorber is similar to that of a dry friction torsional damper, the optimal braking torque to control the torsional vibration is determined and validated by simulation. The optimal design problem of the MR brake absorber is then developed and a procedure to solve the optimal problem is proposed. Based on the proposed optimal design procedure, the optimal design of a specific rotating shaft system is performed. Vibration control performance of the shaft system employing the optimized MR brake absorber is then investigated through simulation and discussion on the results is given. (paper)

  3. Freshwater Fish Survey of Mathews Brake Water Body - 1980 and 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A Freshwater Fish Survey of Mathews Brake water body including land not within Mathews Brake NWR. Methods included Electroshocker, creel census, and seine.

  4. 49 CFR 571.116 - Standard No. 116; Motor vehicle brake fluids.

    Science.gov (United States)

    2010-10-01

    ... WHEN ADDING BRAKE FLUID. (2) KEEP BRAKE FLUID CLEAN AND DRY. Contamination with dirt, water, petroleum... paraffin. Do not use a standard with an age exceeding three months. (1) Potassium hydrogen phthalate...

  5. Surrogate models for efficient stability analysis of brake systems

    Science.gov (United States)

    Nechak, Lyes; Gillot, Frédéric; Besset, Sébastien; Sinou, Jean-Jacques

    2015-07-01

    This study assesses capacities of the global sensitivity analysis combined together with the kriging formalism to be useful in the robust stability analysis of brake systems, which is too costly when performed with the classical complex eigenvalues analysis (CEA) based on finite element models (FEMs). By considering a simplified brake system, the global sensitivity analysis is first shown very helpful for understanding the effects of design parameters on the brake system's stability. This is allowed by the so-called Sobol indices which discriminate design parameters with respect to their influence on the stability. Consequently, only uncertainty of influent parameters is taken into account in the following step, namely, the surrogate modelling based on kriging. The latter is then demonstrated to be an interesting alternative to FEMs since it allowed, with a lower cost, an accurate estimation of the system's proportions of instability corresponding to the influent parameters.

  6. Stability Control of Vehicle Emergency Braking with Tire Blowout

    Directory of Open Access Journals (Sweden)

    Qingzhang Chen

    2014-01-01

    Full Text Available For the stability control and slowing down the vehicle to a safe speed after tire failure, an emergency automatic braking system with independent intellectual property is developed. After the system has received a signal of tire blowout, the automatic braking mode of the vehicle is determined according to the position of the failure tire and the motion state of vehicle, and a control strategy for resisting tire blowout additional yaw torque and deceleration is designed to slow down vehicle to a safe speed in an expected trajectory. The simulating test system is also designed, and the testing results show that the vehicle can be quickly stabilized and kept in the original track after tire blowout with the emergency braking system described in the paper.

  7. Dynamics Models of Interacting Torques of Hydrodynamic Retarder Braking Process

    Directory of Open Access Journals (Sweden)

    Wenhao Shen

    2013-01-01

    Full Text Available Hydrodynamic retarder is a kind of assist braking device, which can transfer the vehicle kinetic energy into the heat energy of working medium. There are complicated three-dimensional viscous incompressible turbulent flows in hydrodynamic retarder, so that it is difficult to represent the parameters changing phenomenon and investigate the interactional law. In order to develop a kind of reliable theoretical model for internal flow field, in this study, the dynamics models of interacting torques between impellers and working fluid were constructed based on braking energy transfer principle by using Euler theory to describe the flow state in view of time scale. The model can truly represent the dynamic braking process.

  8. Braking Performance of a Biomimetic Squid-Like Underwater Robot

    Institute of Scientific and Technical Information of China (English)

    Md.Mahbubar Rahman; Sinpei Sugimori; Hiroshi Miki; Risa Yamamoto; Yugo Sanada; Yasuyuki Toda

    2013-01-01

    In this study,the braking performance of the undulating fin propulsion system ofa biomimetic squid-like underwater robot was investigated through free run experiment and simulation of the quasi-steady mathematical model.The quasi-steady equations of motion were solved using the measured and calculated hydrodynamic forces and compared with free-run test results.Various braking strategies were tested and discussed in terms of stopping ability and the forces acting on the stopping stage.The stopping performance of the undulating fin propulsion system tured out to be excellent considering the short stopping time and short stopping distance.This is because of the large negative thrust produced by progressive wave in opposite direction.It was confirmed that the undulating fin propulsion system can effectively perform braking even in complex underwater explorations.

  9. Simplified model of eddy current brakes and its use for optimization

    OpenAIRE

    Holtmann, Christoph/C.H.; Rinderknecht, Frank/F.R.; Friedrich, Horst E./H.E.F.

    2015-01-01

    The electrification of vehicles makes it possible to think about new concepts to substitute conventional technologies. For example in an electrical drive train, with a traction motor for each wheel mechanical friction brakes can be replaced by eddy current brakes. In this work a method for optimizing the torque density of eddy current brakes is presented. For a fast optimization process the model of the eddy current brake is split up in two levels of detail. In the first level a global model ...

  10. Investigation of Friction Behaviors of Brake Shoe Materials using Metallic Filler

    OpenAIRE

    E. Surojo; Jamasri; V. Malau; M.N. Ilman

    2015-01-01

    Some vehicles use brake shoe made from semi-metallic materials. Semi-metallic brake shoes are made from a combination of metallic and non-metallic materials. Metallic particles are added in the formulation of brake shoe material to improve composites characteristics. In this paper, friction behaviors of brake shoe material using metallic filler were investigated. Machining chips of cast iron and copper wire of electric motor used were incorporated in composite as metallic fillers with amount ...

  11. EFFECT OF GENDER DIFFERENCE ON BRAKE REACTION TIME

    Directory of Open Access Journals (Sweden)

    Ashok

    2016-02-01

    Full Text Available BACKGROUND OF THE STUDY Reaction time is the time taken to respond to a stimulus or change in the environment. It is a method to assess the time taken from the perception of a stimulus followed by mental processing for a motor response. Reaction time in various day to day activities as in driving a car is very important. Brake reaction time (BRT is the time taken for the driver to respond to visualize an object and to press the brake pedal. It is affected by many features like age, gender, neuromuscular disorders. OBJECTIVE OF THE STUDY Study has been undertaken to compare the BRT in male and female drivers and to analyze the effect of sex difference on Brake reaction time. MATERIALS & METHODS Male and female subjects between the age group of 25 – 35 years with driving license were included. Study is conducted in a stationary car. An in-house built; braking timer is fixed to the electric circuit of the braking system in the car. This device is wirelessly connected to the reaction time software installed in the laptop. The subject is instructed to press the brake pedal when the light changed from red to green in the laptop screen. 5 readings are taken and the mean BRT is recorded. STATISTICAL ANALYSIS & RESULTS Statistical analysis done with unpaired student t test indicates that the BRT was more in the females than the males and was statistically significant (p value - 0007. CONCLUSION Gender difference has a significant effect on BRT and reaction time in female is longer than for the males.

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

    Directory of Open Access Journals (Sweden)

    Jiankun Peng

    2015-01-01

    Full Text Available 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.

  13. 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.

  14. 49 CFR 232.503 - Process to introduce new brake system technology.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Process to introduce new brake system technology... Technology § 232.503 Process to introduce new brake system technology. (a) Pursuant to the procedures... brake system technology, prior to implementing the plan. (b) Each railroad shall complete a...

  15. METHODOLOGY FOR PARAMETER CALCULATION OF DISK BRAKE MECHANISMS WITH HYDRAULIC CONTROL

    Directory of Open Access Journals (Sweden)

    O. S. Rukteshel

    2014-11-01

    Full Text Available The paper describes a new methodology for a parameter calculation of a disk brake mechanism with hydraulic control that allows to determine a value of hysteresis losses in a brake at the design stage with high accuracy. A complex analysis for obtaining qualitative and quantitative evaluation of design brake parameter influence on hysteresis value in it is presented in the paper.

  16. 49 CFR 232.207 - Class IA brake tests-1,000-mile inspection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Class IA brake tests-1,000-mile inspection. 232... Class IA brake tests—1,000-mile inspection. (a) Except as provided in § 232.213, each train shall receive a Class IA brake test performed by a qualified person, as defined in § 232.5, at a location...

  17. Correcting Students' Misconceptions about Automobile Braking Distances and Video Analysis Using Interactive Program Tracker

    Science.gov (United States)

    Hockicko, Peter; Trpišová, Beáta; Ondruš, Ján

    2014-01-01

    The present paper informs about an analysis of students' conceptions about car braking distances and also presents one of the novel methods of learning: an interactive computer program Tracker that we used to analyse the process of braking of a car. The analysis of the students' conceptions about car braking distances consisted in…

  18. Thermal-mechanical coupled analysis of a brake disk rotor

    Science.gov (United States)

    Belhocine, Ali; Bouchetara, Mostefa

    2013-08-01

    The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disk and pads during the braking phase. The simulation strategy is based on computer 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 with coupling to determine the deformation and the Von Mises stress established in the disk, the contact pressure distribution in pads. The results are satisfactory when compared to those of the specialized literature.

  19. Fallback level concepts for conventional and by-wire automotive brake systems

    International Nuclear Information System (INIS)

    Brake-by-wire represents the replacement of traditional brake components such as pumps, hoses, fluids, brake boosters, and master cylinders by electronic sensors and actuators. The different design of these brake concepts poses new challenges for the automotive industry with regard to availability and fallback levels in comparison to standard conventional brake systems. This contribution focuses on the development of appropriate fallback level concepts. Hardware-in-the-loop (HIL) techniques and field trials will be used to investigate the performance and the usability of such systems.

  20. Analysis of nanoparticles released from the car brakes

    Czech Academy of Sciences Publication Activity Database

    Švábenská, Eva; Roupcová, Pavla; Schneeweiss, Oldřich

    Ostrava: Tanger, 2015. ISBN 978-80-87294-59-8. [NANOCON 2015. International Conference /7./. Brno (CZ), 14.10.2015-16.10.2015] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : nanoparticles * wear debris * automotive brake Subject RIV: JJ - Other Materials

  1. T-type channels: release a brake, engage a gear

    Czech Academy of Sciences Publication Activity Database

    Weiss, Norbert; Laconova, L.

    2016-01-01

    Roč. 10, č. 2 (2016), s. 78-80. ISSN 1933-6950 Institutional support: RVO:61388963 Keywords : gating brake * pore opening * Ca(V)3.3 Subject RIV: CE - Biochemistry Impact factor: 2.410, year: 2014 http://www.tandfonline.com/doi/pdf/10.1080/19336950.2015.1106655

  2. Computational thermo-fluid analysis of a disk brake

    Science.gov (United States)

    Takizawa, Kenji; Tezduyar, Tayfun E.; Kuraishi, Takashi; Tabata, Shinichiro; Takagi, Hirokazu

    2016-06-01

    We present computational thermo-fluid analysis of a disk brake, including thermo-fluid analysis of the flow around the brake and heat conduction analysis of the disk. The computational challenges include proper representation of the small-scale thermo-fluid behavior, high-resolution representation of the thermo-fluid boundary layers near the spinning solid surfaces, and bringing the heat transfer coefficient (HTC) calculated in the thermo-fluid analysis of the flow to the heat conduction analysis of the spinning disk. The disk brake model used in the analysis closely represents the actual configuration, and this adds to the computational challenges. The components of the method we have developed for computational analysis of the class of problems with these types of challenges include the Space-Time Variational Multiscale method for coupled incompressible flow and thermal transport, ST Slip Interface method for high-resolution representation of the thermo-fluid boundary layers near spinning solid surfaces, and a set of projection methods for different parts of the disk to bring the HTC calculated in the thermo-fluid analysis. With the HTC coming from the thermo-fluid analysis of the flow around the brake, we do the heat conduction analysis of the disk, from the start of the breaking until the disk spinning stops, demonstrating how the method developed works in computational analysis of this complex and challenging problem.

  3. Oxygen-Diffused Titanium as a Candidate Brake Rotor Material

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Jolly, Brian C [ORNL

    2009-01-01

    Titanium alloys are one of several candidate materials for the next generation of truck disk brake rotors. Despite their advantages of lightweight relative to cast iron and good strength and corrosion resistance, titanium alloys are unlikely to be satisfactory brake rotor materials unless their friction and wear behavior can be significantly improved. In this study, a surface engineering process oxygen diffusion was applied to titanium rotors and has shown very encouraging results. The oxygen diffused Ti-6Al-4V (OD-Ti) was tested on a sub-scale brake tester against a flat block of commercial brake lining material and benchmarked against several other Ti-based materials, including untreated Ti-6Al-4V, ceramic particle-reinforced Ti composites (MMCs), and a thermal-spray-coated Ti alloy. With respect to friction, the OD-Ti outperformed all other candidate materials under the imposed test conditions with the friction coefficient remaining within a desirable range of 0.35-0.50, even under the harshest conditions when the disk surface temperature reached nearly 600 C. In addition, the OD-Ti showed significantly improved wear-resistance over the non-treated one and was even better than the Ti-based composite materials.

  4. Electromechanical design and optimization of electromagnetic brake for rail vehicles

    Czech Academy of Sciences Publication Activity Database

    Doležel, Ivo; Moravec, J.; Sedláček, J.; Ulrych, B.

    Lausanne: House EPFL Lausanne, 2005, s. 1-5. [Symposium on Advanced Electromechanical Motion Systems /6/ [0204121]. Lausanne (CH), 27.09.2005-29.09.2005] Institutional research plan: CEZ:AV0Z20570509 Keywords : optimization electromagnetic brake Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. A Laboratory Activity on the Eddy Current Brake

    Science.gov (United States)

    Molina-Bolivar, J. A.; Abella-Palacios, A. J.

    2012-01-01

    The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and…

  6. Non-resonant magnetic braking on JET and TEXTOR

    DEFF Research Database (Denmark)

    Sun, Y.; Liang, Y.; Shaing, K.C.;

    2012-01-01

    The non-resonant magnetic braking effect induced by a non-axisymmetric magnetic perturbation is investigated on JET and TEXTOR. The collisionality dependence of the torque induced by the n = 1, where n is the toroidal mode number, magnetic perturbation generated by the error field correction coil...

  7. 16 CFR 1512.5 - Requirements for braking system.

    Science.gov (United States)

    2010-01-01

    ... as determined by the equivalent ground speed specified in § 1512.18(d)(2)(vi). (2) Hand lever access. Hand lever mechanisms shall be located on the handlebars in a position that is readily accessible to... dimension between the brake hand lever and the handlebars in the plane containing the centerlines of...

  8. Analysis of the surface layer of the brake disk

    Czech Academy of Sciences Publication Activity Database

    Švábenská, Eva; Roupcová, Pavla; Podstranská, Ivana; Petr, M.; Filip, J.; Schneeweiss, Oldřich

    Ostrava : TANGER Ltd, 2015. ISBN 978-80-87294-58-1. [METAL 2015. International Conference on Metallurgy and Materials /24./. Brno (CZ), 03.06.2015-05.06.2015] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : grey cast iron * brake disk * microstructure analysis * surface layer Subject RIV: JG - Metallurgy

  9. Wear and related characteristics of an aircraft tire during braking

    Science.gov (United States)

    Mccarty, J. L.

    1972-01-01

    Wear and related characteristics of friction and temperature developed during braking of size 22 x 5.5, type aircraft tires are studied. The testing technique involved gearing the tire to a driving wheel of a ground vehicle to provide operations at constant slip ratios on asphalt, concrete, and slurry-seal surfaces. Data were obtained over the range of slip ratios generally attributed to an aircraft braking system during dry runway operations. The results show that the cumulative tire wear varies linearly with distance traveled and the wear rate increases with increasing slip ratio and is influenced by the runway-surface character. Differences in the wear rates associated with the various surfaces suggest that runways can be rated on the basis of tire wear. The results also show that the friction coefficients developed during fixed-slip-ratio operations are in good agreement with those obtained by other investigators during cyclic braking, in that the dry friction is insensitive to the tire tread temperature is shown to increase with increasing slip ratio and, at the higher ratios, to be greater during braking on asphalt and slurry seal than on concrete.

  10. Chinese Enterprises Slams the Brakes on Acquisition of Overseas Mines

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>On June 25,China Mining Association revealed that,as of the middle of June,Chinese enterprises slammed the brakes on acquisition of overseas mines.There are only 53 overseas mine acquisition cases so far this year,

  11. Theoretical and experimental studies on a magnetorheological brake operating under compression plus shear mode

    Science.gov (United States)

    Sarkar, C.; Hirani, H.

    2013-11-01

    The torque characteristics of magnetorheological brakes, consisting of rotating disks immersed in a MR fluid and enclosed in an electromagnetic casing, are controlled by regulating the yield stress of the MR fluid. An increase in yield stress increases the braking torque, which means that the higher the yield strength of the MR fluid, the better the performance of the MR brake will be. In the present research an application of compressive force on MR fluid has been proposed to increase the torque capacity of MR brakes. The mathematical expressions to estimate the torque values for MR brake, operating under compression plus shear mode accounting Herschel-Bulkley shear thinning model, have been detailed. The required compressive force on MR fluid of the proposed brake has been applied using an electromagnetic actuator. The development of a single-plate MR disk brake and an experimental test rig are described. Experiments have been performed to illustrate braking torque under different control currents (0.0-2.0 A). The torque results have been plotted and compared with theoretical study. Experimental results as well as theoretical calculations indicate that the braking torque of the proposed MR brake is higher than that of the MR brake operating only under shear.

  12. Theoretical and experimental studies on a magnetorheological brake operating under compression plus shear mode

    International Nuclear Information System (INIS)

    The torque characteristics of magnetorheological brakes, consisting of rotating disks immersed in a MR fluid and enclosed in an electromagnetic casing, are controlled by regulating the yield stress of the MR fluid. An increase in yield stress increases the braking torque, which means that the higher the yield strength of the MR fluid, the better the performance of the MR brake will be. In the present research an application of compressive force on MR fluid has been proposed to increase the torque capacity of MR brakes. The mathematical expressions to estimate the torque values for MR brake, operating under compression plus shear mode accounting Herschel–Bulkley shear thinning model, have been detailed. The required compressive force on MR fluid of the proposed brake has been applied using an electromagnetic actuator. The development of a single-plate MR disk brake and an experimental test rig are described. Experiments have been performed to illustrate braking torque under different control currents (0.0–2.0 A). The torque results have been plotted and compared with theoretical study. Experimental results as well as theoretical calculations indicate that the braking torque of the proposed MR brake is higher than that of the MR brake operating only under shear. (paper)

  13. 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.

  14. Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation

    Science.gov (United States)

    Wibowo, Zakaria, Lambang, Lullus; Triyono, Muhayat, Nurul

    2016-03-01

    The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. The result of measurements can be altered by varying brake fluid pressure.

  15. Synthesis and Characterization of Antifriction Magnetorheological Fluids for Brake

    Directory of Open Access Journals (Sweden)

    Chiranjit Sarkar

    2013-07-01

    Full Text Available Magnetorheological (MR fluids are smart materials with shear strength ranging between zero to 100 kPa under the influence of magnetic field. The present paper discusses the synthesis of MR fluid and its application in brake. In MR brake, gap between stator and rotor is filled with low (off-state viscosity MR fluid. On the application of magnetic field, MR fluid changes its state from liquid to semi-solid by aligning magnetic particles in chains. Due to such chaining action, yield strength of fluid increases, friction between stator and rotor increases and fulfils the braking function. The strength of magnetic particle is a function of relative speed between stator and rotor, applied magnetic field, and volume percentage of magnetic particle. In this study antifriction (off-state and strong chain (on-state CI based MR fluid has been prepared by mixing oleic acid as antifriction additives and tetramethylammonium hydroxide as surfactant to reduce the agglomeration of the MR fluid. Yield strengths of the synthesized MR fluid in on-state and off-state have been compared with commercially available MRF 241ES fluid. A flywheel based MR brake experimental setup has been developed to analyze the performance of designed and developed MR brake.Results show that synthesized MR fluid is stronger and faster in response compared to MRF 241ES fluid.Defence Science Journal, 2013, 63(4, pp.408-412, DOI:http://dx.doi.org/10.14429/dsj.63.2633

  16. Real-world emission factors for antimony and other brake wear related trace elements: size-segregated values for light and heavy duty vehicles.

    Science.gov (United States)

    Bukowiecki, Nicolas; Lienemann, Peter; Hill, Matthias; Figi, Renato; Richard, Agnes; Furger, Markus; Rickers, Karen; Falkenberg, Gerald; Zhao, Yongjing; Cliff, Steven S; Prevot, Andre S H; Baltensperger, Urs; Buchmann, Brigitte; Gehrig, Robert

    2009-11-01

    Hourly trace element measurements were performed in an urban street canyon and next to an interurban freeway in Switzerland during more than one month each, deploying a rotating drum impactor (RDI) and subsequent sample analysis by synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). Antimony and other brake wear associated elements were detected in three particle size ranges (2.5-10, 1-2.5, and 0.1-1 microm). The hourly measurements revealed that the effect of resuspended road dust has to be taken into account for the calculation of vehicle emission factors. Individual values for light and heavy duty vehicles were obtained for stop-and-go traffic in the urban street canyon. Mass based brake wear emissions were predominantly found in the coarse particle fraction. For antimony, determined emission factors were 11 +/- 7 and 86 +/- 42 microg km(-1) vehicle(-1) for light and heavy duty vehicles, respectively. Antimony emissions along the interurban freeway with free-flowing traffic were significantly lower. Relative patterns for brake wear related elements were very similar for both considered locations. Beside vehicle type specific brake wear emissions, road dust resuspension was found to be a dominant contributor of antimony in the street canyon. PMID:19924925

  17. Heavy and Overweight Vehicle Brake Testing: Five-Axle Combination Tractor-Flatbed Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lascurain, Mary Beth [ORNL; Capps, Gary J [ORNL; Franzese, Oscar [ORNL

    2013-10-01

    The Federal Motor Carrier Safety Administration, in coordination with the Federal Highway Administration, sponsored the Heavy and Overweight Vehicle Brake Testing (HOVBT) program in order to provide information about the effect of gross vehicle weight (GVW) on braking performance. Because the Federal Motor Carrier Safety Regulations limit the number of braking system defects that may exist for a vehicle to be allowed to operate on the roadways, the examination of the effect of brake defects on brake performance for increased loads is also relevant. The HOVBT program seeks to provide relevant information to policy makers responsible for establishing load limits, beginning with providing test data for a combination tractor/trailer. This testing was conducted on a five-axle combination vehicle with tractor brakes meeting the Reduced Stopping Distance requirement rulemaking. This report provides a summary of the testing activities, the results of various analyses of the data, and recommendations for future research. Following a complete brake rebuild, instrumentation, and brake burnish, stopping tests were performed from 20 and 40 mph with various brake application pressures (15 psi, 25 psi, 35 psi, 45 psi, 55 psi, and full system pressure). These tests were conducted for various brake conditions at the following GVWs: 60,000, 80,000, 91,000, 97,000, 106,000, and 116,000 lb. The 80,000-lb GVWs included both balanced and unbalanced loads. The condition of the braking system was also varied. To introduce these defects, brakes (none, forward drive axle, or rear trailer axle) were made inoperative. In addition to the stopping tests, performance-based brake tests were conducted for the various loading and brake conditions. Analysis of the stopping test data showed the stopping distance to increase with load (as expected) and also showed that more braking force was generated by the drive axle brakes than the trailer axle brakes. The constant-pressure stopping test data

  18. Use of a hydraulic brake as a source of thermal energy for the railway rolling stock

    Directory of Open Access Journals (Sweden)

    V.A.Gabrinets

    2012-12-01

    Full Text Available Introduction: In this paper the braking issues of passenger trains which have a great speed and frequent stops are examines. Problem statement: These processes are ехpensive and have big energy losses. The proposed solution to the problem: The kinetic energy of braking prosses propose to turn into thermal energy of heating fluid. For this purpose special hydraulic brake is proposed. The brake is connected with the wheel carriage pairs. The process is based on the energy dissipation in liqid when the disks with spikes rotate in it. Because the real liquid has friction and viscosity, it will be heat up, when the mechanical parts of the hydraulic brake are moved in it. The design, operating principle and characteristics of the hydraulic brake are proposed. Transmission of kinetic energy of carriage motion to brake system executed by mechanical clutches. It connected with the wheel pair and transmitting the energy the wheels rotation to hydraulic brake discs. The cylindrical rods are installed on the discs. Rods location fits the profile of the curved centrifugal pump vanes. As result, the fluid heatind prosess by rotatinge discs with rods take place also at the same time with the liquid pumping through the inner volume of brake system.Conclusions: Affordable passenger carriage braking dynamic is achieved by varying the size and number of rods. The heated liquid may be subsequently used for household needs and for heating the passenger carriage.

  19. Differential Rotation in Neutron Stars Magnetic Braking and Viscous Damping

    CERN Document Server

    Shapiro, S L

    2000-01-01

    Diffferentially rotating stars can support significantly more mass in equilibrium than nonrotating or uniformly rotating stars, according to general relativity. The remnant of a binary neutron star merger may give rise to such a ``hypermassive'' object. While such a star may be dynamically stable against gravitational collapse and bar formation, the radial stabilization due to differential rotation is likely to be temporary. Magnetic braking and viscosity combine to drive the star to uniform rotation, even if the seed magnetic field and the viscosity are small. This process inevitably leads to delayed collapse, which will be accompanied by a delayed gravitational wave burst and, possibly, a gamma-ray burst. We provide a simple, Newtonian, MHD calculation of the braking of differential rotation by magnetic fields and viscosity. The star is idealized as a differentially rotating, infinite cylinder consisting of a homogeneous, incompressible conducting gas. We solve analytically the simplest case in which the ga...

  20. Syntegra: complete integration of traction, bogie and brake systems

    Energy Technology Data Exchange (ETDEWEB)

    Loewenstein, L.; Wangelin, F. von [Siemens AG, Transportation Systems, Erlangen (Germany). Group Technology TS GT; Teichmann, M.; Hoffmann, T. [Siemens TS, Graz (Austria); Joeckel, A. [Siemens Automation and Drives, Nuernberg (Germany)

    2007-07-01

    With Syntegra {sup registered} technology, Siemens has developed an approach to the complete integration of traction, bogie and brake systems, and this has initially been put into practice for metro, underground and S-Bahn (urban regional express) trains. Syntegra constitutes a fundamentally new approach, achieving a greater intensity of integration compared with the types of drive system that have been in use up until now. With Syntegra, the bogie, transmission and brake components are all brought together as part of one and the same system. The integration and, more especially, the technological advances within the three named areas bring about numerous synergies. The new generation of powered bogie features a combination of high efficiency, low dead weight and reduced emissions. A Syntegra drive system achieves a performance which is markedly better than that of conventional systems. (orig.)

  1. 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...

  2. Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit

    Science.gov (United States)

    Mellon, Richard R.; Li, Zhi-Yun

    2008-07-01

    Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (λ lesssim 1). We show that, in disk formation, the requirement is far less stringent. This conclusion is drawn from a set of 2D (axisymmetric) simulations of the collapse of rotating, singular isothermal cores magnetized to different degrees. We find that a weak field corresponding to λ ~ 100 can begin to disrupt the rotationally supported disk through magnetic braking, by creating regions of rapid, supersonic collapse in the disk. These regions are separated by one or more centrifugal barriers, where the rapid infall is temporarily halted. The number of centrifugal barriers increases with the mass-to-flux ratio λ. When λ gtrsim 100, they merge together to form a more or less contiguous, rotationally supported disk. Even though the magnetic field in such a case is extremely weak on the scale of dense cores, it is amplified by collapse and differential rotation, to the extent that its pressure dominates the thermal pressure in both the disk and its surrounding region. For relatively strongly magnetized cores with λ lesssim 10, the disk formation is suppressed completely, as found previously. A new feature is that the mass accretion is highly episodic, due to reconnection of the magnetic field lines accumulated near the center. For rotationally supported disks to appear during the protostellar mass accretion phase of star formation in dense cores with realistic field strengths, the powerful magnetic brake must be weakened, perhaps through nonideal MHD effects. Another possibility is to remove, through protostellar winds, the material that acts to brake the disk rotation. We discuss the possibility of observing a generic product of the magnetic braking, an extended circumstellar region that is supported by a combination of toroidal magnetic field and rotation—a "magnetogyrosphere"—interferometrically.

  3. Subway Train Braking System: A Fuzzy Based Hardware Approach

    Directory of Open Access Journals (Sweden)

    Mamun B.I. Reaz

    2011-01-01

    Full Text Available Problem statement: Automated subway train-braking system require perfection, efficiency and fast response. In order to cope with this concerns, an appropriate algorithm need to be developed which need to be implemented in hardware for faster response. Approach: In this research, the FPGA realization of fuzzy based subway train braking system has been presented on an Alter FLEX10K device to provide an accurate and increased speed of convergence of the network. The fuzzy based subway train braking system is comprised of fusilier, inference, rule selector and defuzzifier modules. Sixteen rules are identified for the rule selector module. After determining the membership functions and its fuzzy variables, the Max-Min Composition method and Madman-Min implication operator are used for the inference module and the Centre of Gravity method is used for the defuzzification module. Each module is modeled individually using behavioral VHDL. The layers are then connected using structural VHDL. Two 8-bit and one 8-bit unsigned digital signals are used for input and output respectively. Six ROMs are defined in order to decrease the chances of processing and increasing the throughput of the system. Results: Functional simulations were commenced to verify the functionality of the individual modules and the system as well. We have validated the hardware implementation of the proposed approach through comparison, verification and analysis. The design has utilized 2372 units of LC with a system frequency of 139.8MHz. Conclusion: In this research, the FPGA realization of fuzzy brake system of subway train has been successfully implemented with minimum usage of logic cells. The validation study with C model shows that the hardware model is appropriate and the hardware approach shows faster and accurate response with full automatic control.

  4. Differential Rotation in Neutron Stars: Magnetic Braking and Viscous Damping

    OpenAIRE

    Shapiro, Stuart L.

    2000-01-01

    Diffferentially rotating stars can support significantly more mass in equilibrium than nonrotating or uniformly rotating stars, according to general relativity. The remnant of a binary neutron star merger may give rise to such a ``hypermassive'' object. While such a star may be dynamically stable against gravitational collapse and bar formation, the radial stabilization due to differential rotation is likely to be temporary. Magnetic braking and viscosity combine to drive the star to uniform ...

  5. Carbon nanotube torsional springs for regenerative braking systems

    Science.gov (United States)

    Liu, Sanwei; Martin, Corbin; Lashmore, David; Schauer, Mark; Livermore, Carol

    2015-10-01

    The modeling and demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as energy-storing actuators for regenerative braking systems. An originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing incrementally until failure. The measured average extractable energy density values are 2.9 kJ kg-1  ±  1.2 kJ kg-1 and 3.4 kJ kg-1  ±  0.4 kJ kg-1 for 1-ply CNT yarns and 2-ply CNT yarns, respectively. Additionally, a regenerative braking system is demonstrated to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yarn’s twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking setup are on average 3.3 kJ kg-1 and 0.67 kW kg-1, respectively, with maximum measured values of up to 4.7 kJ kg-1 and 1.2 kW kg-1, respectively. A slightly lower energy density of up to 1.2 kJ kg-1 and a 0.29 kW kg-1 mean power density are measured for CNT yarns in a more complex setup that mimics a unidirectional rotating regenerative braking mechanism.

  6. 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.

  7. Neural Signatures Enhance Emergency Braking Intention Detection during Simulated Driving

    OpenAIRE

    Stefan Haufe; M. F. Gugler; Sagebaum, M.

    2010-01-01

    In many safety-critical areas such as individual car traffic, human performance has become the limiting factor. Modern driving assistance systems can detect potential upcoming crashes and take preparatory measures or even initiate automatic emergency braking.We conducted a driving simulator study (N=20) using a customized version of the open-source racing software TORCS. The experiment comprised 3 blocks (45 minutes each) of driving, in which the subjects had to tightly follow a computer-cont...

  8. SPINDOWN OF ISOLATED NEUTRON STARS: GRAVITATIONAL WAVES OR MAGNETIC BRAKING?

    International Nuclear Information System (INIS)

    We study the spindown of isolated neutron stars from initially rapid rotation rates, driven by two factors: (1) gravitational wave emission due to r-modes and (2) magnetic braking. In the context of isolated neutron stars, we present the first study including self-consistently the magnetic damping of r-modes in the spin evolution. We track the spin evolution employing the RNS code, which accounts for the rotating structure of neutron stars for various equations of state. We find that, despite the strong damping due to the magnetic field, r-modes alter the braking rate from pure magnetic braking for B ≤ 1013 G. For realistic values of the saturation amplitude αsat, the r-mode can also decrease the time to reach the threshold central density for quark deconfinement. Within a phenomenological model, we assess the gravitational waveform that would result from r-mode-driven spindown of a magnetized neutron star. To contrast with the persistent signal during the spindown phase, we also present a preliminary estimate of the transient gravitational wave signal from an explosive quark-hadron phase transition, which can be a signal for the deconfinement of quarks inside neutron stars.

  9. 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.

  10. Neuroendocrine brake for the treatment of morbid obesity. Preliminary report

    Directory of Open Access Journals (Sweden)

    Aureo Ludovico de Paula

    2005-06-01

    Full Text Available Objectives: To demonstrate the preliminary results of a newtechnique named neuroendocrine brake, for surgical treatment ofmorbid obesity. Methods: In November 2003, three patientsunderwent the neuroendocrine brake operation performed by thelaparoscopic approach. The mean age was 46.4 years; all patientswere female. Mean BMI was 42.3 kg/m2. The patients selectedpresented some relative or absolute contraindications to the useof gastrointestinal bypass techniques, including gastric ulcer anda family history of gastric malignancy(1 and chronic anemia (2.All patients had associated diseases, including type II diabetesmellitus (2, hypertension (2, obstructive sleep apnea (1,dyslipidemia (3, cholecystolithiasis (1, gastric ulcer (1 andchronic anemia (2. The laparoscopic technique consisted of anileal interposition at the proximal jejunum and longitudinalgastrectomy. Results: There was no conversion to open surgery orpostoperative complications. Sixteen months later, the meanpercentage of initial body weight loss was 44.6% and the meanBMI was 24.3 kg/m2. Glucose, triglyceride and cholesterol levelswere normalized, and sleep apnea showed remission. Conclusion:In spite of the reduced number of patients and short term followup, the good results suggest that the neuroendocrine brake maybecome an option for surgical treatment of morbid obesity in thenear future.

  11. Mechanism analysis and evaluation methodology of regenerative braking contribution to energy efficiency improvement of electrified vehicles

    International Nuclear Information System (INIS)

    Highlights: • The energy flow of an electric vehicle with regenerative brake is analyzed. • Methodology for measuring the regen brake contribution is discussed. • Evaluation parameters of regen brake contribution are proposed. • Vehicle tests are carried out on chassis dynamometer. • Test results verify the evaluation method and parameters proposed. - Abstract: This article discusses the mechanism and evaluation methods of contribution brought by regenerative braking to electric vehicle’s energy efficiency improvement. The energy flow of an electric vehicle considering the braking energy regeneration was analyzed. Then, methodologies for measuring the contribution made by regenerative brake to vehicle energy efficiency improvement were introduced. Based on the energy flow analyzed, two different evaluation parameters were proposed. Vehicle tests were carried out on chassis dynamometer under typical driving cycles with three different control strategies. The experimental results the difference between the proposed two evaluation parameters, and demonstrated the feasibility and effectiveness of the evaluation methodologies proposed

  12. A Combined Cooperative Braking Model with a Predictive Control Strategy in an Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Hongqiang Guo

    2013-12-01

    Full Text Available Cooperative braking with regenerative braking and mechanical braking plays an important role in electric vehicles for energy-saving control. Based on the parallel and the series cooperative braking models, a combined model with a predictive control strategy to get a better cooperative braking performance is presented. The balance problem between the maximum regenerative energy recovery efficiency and the optimum braking stability is solved through an off-line process optimization stream with the collaborative optimization algorithm (CO. To carry out the process optimization stream, the optimal Latin hypercube design (Opt LHD is presented to discrete the continuous design space. To solve the poor real-time problem of the optimization, a high-precision predictive model based on the off-line optimization data of the combined model is built, and a predictive control strategy is proposed and verified through simulation. The simulation results demonstrate that the predictive control strategy and the combined model are reasonable and effective.

  13. Detecting groan sources in drum brakes of commercial vehicles by TVA-FMEA

    OpenAIRE

    Karabay, Sedat; Baynal, Kasim; İğdeli, Cengiz

    2015-01-01

    In this article, the strategy followed by an automobile company for detecting the root causes of groan complaints related to rear drum brakes in commercial vehicles is presented using data collected from the sold troubled vehicles and from new vehicles from the production line, as well as the drum-brake test rig at the laboratory. Drum brake groan is often very intense and can cause large numbers of customer complaints. During a groan noise event, vehicle structure and suspension components a...

  14. Detecting groan sources in drum brakes of commercial vehicles by TVA-FMEA: a case study:

    OpenAIRE

    Baynal, Kasim; Igdeli, Cengiz; Karabay, Sedat

    2013-01-01

    In this article, the strategy followed by an automobile company for detecting the root causes of groan complaints related to rear drum brakes in commercial vehicles is presented using data collected from the sold troubled vehicles and from new vehicles from the production line, as well as the drum-brake test rig at the laboratory. Drum brake groan is often very intense and can cause large numbers of customer complaints. During a groan noise event, vehicle structure and suspension components a...

  15. Experimental characterization and numerical modelling of the squeal noise generated by railway disc brakes

    OpenAIRE

    CHIELLO,O; LORANG,X; Cordier, JF; MARGIOCCHI,F

    2007-01-01

    The squeal noise generated by railway disk brakes is an everyday source of discomfort for the passengers both inside and outside the trains in stations. The development of silent brake components is needed but beforehand requires a better characterisation and understanding of the phenomenon. This is the aim of the experimental and theoretical investigations performed on high power disc brakes in the framework of the CRISFIS project and presented in this paper. The first part is concerned with...

  16. An approach of inertia compensation based on electromagnetic induction in brake test

    Directory of Open Access Journals (Sweden)

    Xiaowen Li

    2016-04-01

    Full Text Available This paper briefly introduced the operational principle of the brake test bench, and points out the shortcomings when controlling the current of brake test, which means the reference measuring data is instantaneous. Aimed at this deficiency, a current control model based on electromagnetic induction and DC voltage is proposed. On the principle of electromagnetic induction, continuous data and automatic processes are realized. It significantly minimized errors owing to instantaneous data, and maximized the accuracy of the brake test.

  17. 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 ...

  18. Studies on Horizontal Axis Wind Turbine with Passive Teetered Brake & Damper Mechanism

    OpenAIRE

    Shimizu, Yukimaru; KAMADA, Yasunari; MAEDA, Takao

    1998-01-01

    In order to improve the reliability of megawatt wind turbines, the passive teetered brake & damper mechanism is applied. Its two unique effects, as its name implies, are braking and damping. The passive brake & damper mechanism is useful for variable speed control of the large wind turbine. It is comprised of teetering and feathering mechanisms. When the wind speed exceeds the rated wind speed, the blade is passively teetered in a downwind direction and, at the same time, a feathering mechani...

  19. Radiation

    International Nuclear Information System (INIS)

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  20. Radiation

    International Nuclear Information System (INIS)

    Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

  1. Design of a squeeze film magnetorheological brake considering compression enhanced shear yield stress of magnetorheological fluid

    Science.gov (United States)

    Sarkar, C.; Hirani, H.

    2013-02-01

    A magnetorheological brake, consisting of rotating disks immersed in a MR fluid and enclosed in an electromagnet, is proposed to replace the conventional heavy weight low response hydraulic disk brake. The frictional characteristics of the proposed brake can be controlled by regulating the yield stress of the MR fluid as function of magnetic field and normal compressive force. The controllable yield stress retards the surfaces of rotating disks, thus MR fluid can be used as a brake lining material. The present research work attempts designing a squeeze film MR brake by accounting compression enhanced shear yield stress of magnetorheological fluid. Theoretical calculations indicate that the estimated braking torque of the six plate squeeze film MR brake, under compression, is in the order of 600Nm. To validate the theoretical design and its findings, a prototype of single-plate squeeze film MR disk brake has been developed. Experimental test setup helps to illustrate braking torque under different control currents (0.0 to 1.25 A).

  2. Characteristic Analysis and Control of a Hybrid Excitation Linear Eddy Current Brake

    OpenAIRE

    Baoquan Kou; Yinxi Jin; Lu Zhang; He Zhang

    2015-01-01

    In this paper, a novel hybrid excitation linear eddy current brake is presented as a braking system for high-speed road and rail vehicles. The presence of the permanent magnets (PMs), whose flux lines in the primary core are oppositely directed with respect to the flux lines by the excitation windings, has the effect of mitigating the saturation of the iron in the teeth of the primary core. This allows the brake to be fed with more intense currents, improving the braking force. First, using...

  3. Optimal design of a novel hybrid MR brake for motorcycles considering axial and radial magnetic flux

    International Nuclear Information System (INIS)

    This work presents an optimal solution of a new type of motorcycle brake featuring different smart magnetorheological (MR) fluids. In this study, typical types of commercial MR fluid are considered there for the design of a motorcycle MR brake; MRF-122-2ED (low yield stress), MRF-132-DG (medium yield stress) and MRF-140-CG (high yield stress). As a first step, a new configuration featuring a T-shaped drum MR brake is introduced and a hybrid concept of magnetic circuit (using both axial and radial magnetic flux) to generate braking force is analyzed based on the finite element method. An optimal design of the MR brake considering the required braking torque, the temperature due to friction of the MR fluid, the mass of the brake system and all significant geometric dimensions is then performed. For the optimization, the finite element analysis (FEA) is used to achieve principal geometric dimensions of the MR brake. In addition, the size, mass and power consumption of three different MR motorcycle brakes are quantitatively analyzed and compared. (paper)

  4. Analysis of the stability of PTW riders in autonomous braking scenarios.

    Science.gov (United States)

    Symeonidis, Ioannis; Kavadarli, Gueven; Erich, Schuller; Graw, Matthias; Peldschus, Steffen

    2012-11-01

    While fatalities of car occupants in the EU decreased remarkably over the last decade, Powered Two Wheelers (PTWs) fatalities still increase following the increase of PTW ownership. Autonomous braking systems have been implemented in several types of vehicles and are presently addressed by research in the field of PTWs. A major concern in this context is the rider stability. Experiments with volunteers were performed in order to find out whether autonomous braking for PTWs will produce a greater instability of the rider in comparison to manual braking. The PTW's braking conditions were simulated in a laboratory with a motorcycle mock-up mounted on a sled, which was accelerated with an average of 0.35 g. The motion of the rider was captured in autonomous braking scenarios with and without pre-warning as well as in manual braking scenarios. No significant differences between the scenarios were found with respect to maximum forward displacement of the volunteer's torso and head (pautonomous braking at low deceleration will not cause significant instabilities of the rider in comparison to manual braking in idealized laboratory conditions. Based on this, further research into the development and implementation of autonomous braking systems for PTWs, e.g. by extensive riding tests, seems valuable. PMID:23036398

  5. Gravitational wave emission by the high braking index pulsar PSR J1640-4631

    CERN Document Server

    de Araujo, José C N; Costa, César A

    2016-01-01

    Recently, a braking index for the pulsar PSR J1640-4631 has been measured. With a braking index of $n = 3.15 \\pm 0.03$, this pulsar has the highest braking index ever measured. As it is well known, a pure magnetic dipole brake yields $n = 3$, whereas a pure gravitational wave brake yields $n = 5$. Therefore, each of these mechanisms alone can not account for the braking index found for PSR J1640-4631. Here we show that such a braking index can be accounted for if the spindown model combines magnetic dipole and gravitational wave brakes. Then, we briefly discuss the detectability of this pulsar by aLIGO and the planned Einstein Telescope. In particular, we show that the amplitude of the gravitational wave that comes from our model is around a factor four lower than the amplitude modeled exclusively by gravitational wave energy loss. Another interesting outcome of our modeling is that we are able to obtain the ellipticity from the braking index and other pulsar parameters.

  6. Real-Time Dynamic Brake Assessment Proof of Concept Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lascurain, Mary Beth [ORNL; Franzese, Oscar [ORNL; Capps, Gary J [ORNL

    2011-11-01

    This proof-of-concept research was performed to explore the feasibility of using real-world braking data from commercial motor vehicles to make a diagnosis of brake condition similar to that of the performance-based brake tester (PBBT). This was done by determining the relationship between pressure and brake force (P-BF), compensating for the gross vehicle weight (GVW). The nature of this P-BF relationship (e.g., low braking force for a given brake application pressure) may indicate brake system problems. In order to determine the relationship between brake force and brake application pressure, a few key parameters of duty cycle information were collected. Because braking events are often brief, spanning only a few seconds, a sample rate of 10 Hz was needed. The algorithm under development required brake application pressure and speed (from which deceleration was calculated). Accurate weight estimation was also needed to properly derive the braking force from the deceleration. In order to ensure that braking force was the predominant factor in deceleration for the segments of data used in analysis, the data was screened for grade as well. Also, the analysis needed to be based on pressures above the crack pressure. The crack pressure is the pressure below which the individual brakes are not applied due the nature of the mechanical system. This value, which may vary somewhat from one wheel end to another, is approximately 10 psi. Therefore, only pressures 15 psi and above were used in the analysis. The Department of Energy s Medium Truck Duty Cycle research has indicated that under the real-world circumstances of the test vehicle brake pressures of up to approximately 30 psi can be expected. Several different types of data were collected during the testing task of this project. Constant-pressure stopping tests were conducted at several combinations of brake application pressure (15, 20, 25, and 30 psi), load conditions (moderately and fully laden), and speeds (20 and

  7. 重载列车制动管路对制动性能的影响%Influence of braking pipe on braking performance for heavy haul train

    Institute of Scientific and Technical Information of China (English)

    魏伟; 杜念博

    2011-01-01

    应用流体动力学理论,建立了重载列车制动管路模型与分配阀模型,求解了制动管路和边界点的动力学方程,仿真计算了制动过程中的制动系统性能,分析了列车主管和支管长度对制动系统性能的影响。分析结果表明:当列车主管长度由13.24 m增大为17.24 m时,在常用制动下,列车管路减压时间增大了30.75%,制动缸升压时间增大了20.45%,主管长度对常用制动的影响要强于对紧急制动的影响;当列车支管长度由0.50 m增大到5.00 m时,在常用制动下,列车管路减压时间增大了6.63%,制动缸升压时间增大了5.22%,支管长度对常用制动和紧急制动影响程度差别不大。列车制动管路长度增大降低了列车制动管路减压速度与制动缸升压速度;列车主管长度对制动性能的影响要明显大于列车支管长度的影响,车辆位置距机车越远影响越明显。%With fluid dynamics theory,the models of braking pipe and distributing valve for heavy haul train were built,the equations of braking pipe and boundary point were solved,the braking system performances in braking process were simulated,and the influence of the lengths of main pipe and branch pipe on the braking performances was analyzed.Analysis result shows that under common braking,when the length of main pipe increases from 13.24 m to 17.24 m,the decompression time of braking pipe increases by 30.75%,and the boost time of braking cylinder increases by 20.45%.The influence of main pipe on common braking is even stronger than that of main pipe on emergency braking.Under common braking,when the length of branch pipe increases from 0.50 m to 5.00 m,the decompression time of braking pipe increases by 6.63%,and the boost time of braking cylinder increases by 5.22%.The influence of branch pipe on common braking is almost same for that of branch pipe on emergency braking.The increase length of braking pipe reduces the decompression speed of braking pipe

  8. Analysis of heat conduction in a drum brake system of the wheeled armored personnel carriers

    Science.gov (United States)

    Puncioiu, A. M.; Truta, M.; Vedinas, I.; Marinescu, M.; Vinturis, V.

    2015-11-01

    This paper is an integrated study performed over the Braking System of the Wheeled Armored Personnel Carriers. It mainly aims to analyze the heat transfer process which is present in almost any industrial and natural process. The vehicle drum brake systems can generate extremely high temperatures under high but short duration braking loads or under relatively light but continuous braking. For the proper conduct of the special vehicles mission in rough terrain, we are talking about, on one hand, the importance of the possibility of immobilization and retaining position and, on the other hand, during the braking process, the importance movement stability and reversibility or reversibility, to an encounter with an obstacle. Heat transfer processes influence the performance of the braking system. In the braking phase, kinetic energy transforms into thermal energy resulting in intense heating and high temperature states of analyzed vehicle wheels. In the present work a finite element model for the temperature distribution in a brake drum is developed, by employing commercial finite element software, ANSYS. These structural and thermal FEA models will simulate entire braking event. The heat generated during braking causes distortion which modifies thermoelastic contact pressure distribution drum-shoe interface. In order to capture the effect of heat, a transient thermal analysis is performed in order to predict the temperature distribution transitional brake components. Drum brakes are checked both mechanical and thermal. These tests aim to establish their sustainability in terms of wear and the variation coefficient of friction between the friction surfaces with increasing temperature. Modeling using simulation programs led eventually to the establishment of actual thermal load of the mechanism of brake components. It was drawn the efficiency characteristic by plotting the coefficient of effectiveness relative to the coefficient of friction shoe-drum. Thus induced

  9. Spindown of Isolated Neutron Stars: Gravitational Waves or Magnetic Braking?

    OpenAIRE

    Staff, Jan; Jaikumar, Prashanth; Chan, Vincent; Ouyed, Rachid

    2011-01-01

    We study the spindown of isolated neutron stars from initially rapid rotation rates, driven by two factors: (i) gravitational wave emission due to r-modes and (ii) magnetic braking. In the context of isolated neutron stars, we present the first study including self-consistently the magnetic damping of r-modes in the spin evolution. We track the spin evolution employing the RNS code, which accounts for the rotating structure of neutron stars for various equations of state. We find that, despit...

  10. MAGNETIC BRAKING AND FIELD DISSIPATION IN THE PROTOSTELLAR ACCRETION PHASE

    Directory of Open Access Journals (Sweden)

    D. Galli

    2009-01-01

    Full Text Available We summarize recent theoretical work addressing the role of magnetic elds in the process of star formation. First, we concentrate on the efficiency of magnetic braking during cloud collapse and its consequences on the formation of centrifugally supported disks around young stars. Then, we relate this issue to the well-known magnetic ux problem of star formation, and we show that the introduction of non-ideal MHD e ects is a necessary step toward the development of self-consistent models for the collapse of molecular clouds and the formation and evolution of accretion disks around young stars.

  11. Big brake singularity is accommodated as an exotic quintessence field

    OpenAIRE

    Chimento, Luis P.; Richarte, Martín G.

    2015-01-01

    We describe a big brake singularity in terms of a modified Chaplygin gas equation of state $p=(\\ga_{m}-1)\\rho+\\al\\ga_{m}\\rho^{-n}$, accommodate this late-time event as an exotic quintessence model obtained from an energy-momentum tensor, and focus on the cosmological behavior of the exotic field, its kinetic energy and the potential energy. At the background level, the exotic field does not blow up whereas its kinetic energy and potential both grow without limit near the future singularity. W...

  12. Dynamic Braking System of a Tidal Generator: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard; Wright, Alan; Gevorgian, Vahan; Donegan, James; Marnagh, Cian; McEntee, Jarlath

    2016-08-01

    Renewable energy generation has experienced significant cost reductions during the past decades, and it has become more accepted by the global population. In the beginning, wind generation dominated the development and deployment of renewable energy; however, during recent decades, photovoltaic (PV) generation has grown at a very significant pace due to the tremendous decrease in the cost of PV modules. The focus on renewable energy generation has now expanded to include new types with promising future applications, such as river and tidal generation. The input water flow to these types of resources is more predictable than wind or solar generation. The data used in this paper is representative of a typical river or tidal generator. The analysis is based on a generator with a power rating of 40 kW. The tidal generator under consideration is driven by two sets of helical turbines connected to each side of the generator located in between the turbines. The generator is operated in variable speed, and it is controlled to maximize the energy harvested as well as the operation of the turbine generator. The electrical system consists of a three-phase permanent magnet generator connected to a three-phase passive rectifier. The output of the rectifier is connected to a DC-DC converter to match the rectifier output to the DC bus voltage of the DC-AC inverter. The three-phase inverter is connected to the grid, and it is controlled to provide a good interface with the grid. One important aspect of river and tidal generation is the braking mechanism. In a tidal generator, the braking mechanism is important to avoid a runaway condition in case the connection to the grid is lost when there is a fault in the lines. A runaway condition may lead to an overspeed condition and cause extreme stresses on the turbine blade structure and eventual disintegration of the mechanical structure. In this paper, the concept of the dynamic braking system is developed and investigated for normal

  13. Dynamic Control Applied to a Laboratory Antilock Braking System

    Directory of Open Access Journals (Sweden)

    Cuauhtémoc Acosta Lúa

    2015-01-01

    Full Text Available The control of an antilock braking system is a difficult problem due to the existence of nonlinear dynamics and uncertainties of its characteristics. To overcome these issues, in this work, a dynamic nonlinear controller is proposed, based on a nonlinear observer. To evaluate its performance, this controller has been implemented on an ABS Laboratory setup, representing a quarter car model. The nonlinear observer reconstructs some of the state variables of the setup, assumed not measurable, to establish a fair benchmark for an ABS system of a real automobile. The dynamic controller ensures exponential convergence of the state estimation, as well as robustness with respect to parameter variations.

  14. Parameter Analysis on Torque Stabilization for the Eddy Current Brake: A Developed Model, Simulation, and Sensitive Analysis

    OpenAIRE

    Quan Zhou; Xuexun Guo; Gangfeng Tan; Xiaomeng Shen; Yifan Ye; Zhaohua Wang

    2015-01-01

    Eddy current brake (ECB) is an attractive contactless brake whereas it suffers from braking torque attenuation when the rotating speed increases. To stabilize the ECB’s torque generation property, this paper introduces the concept of anti-magneto-motive force to develop the ECB model on the fundamental of magnetic circles. In the developed model, the eddy current demagnetization and the influence of temperature which make the braking torque attenuation are clearly presented. Using the develop...

  15. Comparing Variability of Parameters between Roller Bed Brakes Testers and Dynamometric Platform of Ministry Of Transport Facilities

    Directory of Open Access Journals (Sweden)

    Senabre C

    2015-01-01

    Full Text Available This study gives a comparison between which parameters may vary when braking on two different Ministry of Transport (MOT brake testers, such as roller bed brake tester and dynamometric platform. A comparative study between both types of brake testers have been carried out by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University in Elche to determinate which parameters can vary the result of the test.

  16. Energy-Regenerative Braking Control of Electric Vehicles Using Three-Phase Brushless Direct-Current Motors

    OpenAIRE

    Bo Long; Shin Teak Lim; Ji Hyoung Ryu; Kil To Chong

    2013-01-01

    Regenerative braking provides an effective way of extending the driving range of battery powered electric vehicles (EVs). This paper analyzes the equivalent power circuit and operation principles of an EV using regenerative braking control technology. During the braking period, the switching sequence of the power converter is controlled to inverse the output torque of the three-phase brushless direct-current (DC) motor, so that the braking energy can be returned to the battery. Compared with ...

  17. Short term braking capability during power interruptions for integrated matrix converter

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    attractive. Sinusoidal input currents and bi-directional power flow are other advantages of the matrix converter, but it is less immune to power grid disturbances compared to a standard ASD. In hoisting applications, short-term braking capability during a power outage is needed until the mechanical brake...

  18. Solid state circuit controls direction, speed, and braking of dc motor

    Science.gov (United States)

    Hanna, M. F.

    1966-01-01

    Full-wave bridge rectifier circuit controls the direction, speed, and braking of a dc motor. Gating in the circuit of Silicon Controlled Rectifiers /SCRS/ controls output polarity and braking is provided by an SCR that is gated to short circuit the reverse voltage generated by reversal of motor rotation.

  19. 76 FR 44829 - Federal Motor Vehicle Safety Standards; Air Brake Systems

    Science.gov (United States)

    2011-07-27

    ... 6x4 tractor with a 190-inch wheelbase, equipped with a hybrid disc brake configuration. The vehicle... National Highway Traffic Safety Administration 49 CFR Part 571 RIN 2127-AK84 Federal Motor Vehicle Safety... published a final rule that amended the Federal motor vehicle safety standard for air brake systems...

  20. Brake wear from vehicles as an important source of diffuse copper pollution

    NARCIS (Netherlands)

    Hulskotte, J.H.J.; Gon, H.A.C.D. van der; Visschedijk, A.J.H.; Schaap, M.

    2007-01-01

    In this article we show that brake wear from road traffic vehicles is an important source of atmospheric (participate) copper concentrations in Europe. Consequently, brake wear also contributes significantly to deposition fluxes of copper to surface waters. We estimated the copper emission due to br

  1. 77 FR 39561 - Advanced Braking Technologies That Rely on Forward-Looking Sensors; Request for Comments

    Science.gov (United States)

    2012-07-03

    ... Sensors; Request for Comments AGENCY: National Highway Traffic Safety Administration (NHTSA), Department... technologies that rely on forward-looking sensors to supplement driver braking or to actuate automatic braking... information from forward-looking sensors, usually a camera or radar, to determine whether or not a crash...

  2. Investigation on hardness and impact resistance of automotive brake pad composed with rice husk dust

    Science.gov (United States)

    Bahari, Shahril Anuar; Isa, Khairul Hafizee; Kassim, Masitah Abu; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    In this study, hardness and impact resistance properties of automotive brake pad composed with rice husk dust (RHD) were documented. RHD was mixed with other metallic and synthetic ingredients of automotive brake pad. To obtain RHD, rice husk was ground and dried to 1 - 3% moisture content. The RHD was screened to obtain different dust sizes (80 and 100-mesh) before it was mixed with other materials at different percentages of composition (10 and 30%). The mixture was then pressed to produce brake pad. Rockwell hardness testing machine was used in hardness determination, while Izod impact testing machine was used in impact resistance determination. Hardness resistance of automotive brake pad mixed with 10% composition and 80-mesh size of RHD was significantly higher than 100-mesh. Hardness resistance of automotive brake pad mixed with 30% composition and 100-mesh size of RHD was slightly higher than 80 mesh. However, based on analysis, the difference was not significant. According to the result, hardness resistance of automotive brake pad mixed with 30% composition of RHD was higher than 10%. RHD has filled up the space and enhanced the micro structural behaviour of automotive brake pad. Impact resistance of automotive brake pad mixed with 10% composition and 80-mesh size of RHD was insignificantly higher than 100-mesh. Impact resistance of automotive brake pad mixed with 30% composition and 80-mesh size of RHD was significantly higher than 100 mesh. Large RHD size has increased the capability to resist high-rated impact loading. The impact energy was distributed over wider area for larger particle size. This factor has increased the impact resistance of automotive brake pad from large dust size. Impact resistance of automotive brake pad mixed with 80-mesh size and 30% composition of RHD was higher than 10%. In contrast, impact resistance of automotive brake pad mixed with 100-mesh size and 10% composition of RHD was higher than 30%. However, the difference was not

  3. Compositions, Functions, and Testing of Friction Brake Materials and Their Additives

    Energy Technology Data Exchange (ETDEWEB)

    Blau, PJ

    2001-10-22

    The purpose of this report is to present a survey of commercial brake materials and additives, and to indicate their typical properties and functions, especially as regards their use in heavy trucks. Most truck pad and shoe materials described here were designed to wear against cast iron. Brake material test methods are also briefly described. This report does not address issues associated with the fabrication and manufacturing of brake materials. Since there are literally thousands of brake material additives, and their combinations are nearly limitless, it is impractical to list them all here. Rather, an attempt has been made to capture the primary constituents and their functions. An Appendix contains thermo-physical properties of some current and potential brake materials.

  4. Effect of Road Adhesion Coefficient on Tractor-Semitrailer Cornering Braking Stability

    Science.gov (United States)

    Wang, Wei; Li, Chen; Tang, Geteng; Wang, Cheng

    A dynamic model of tractor-semitrailer cornering braking was established in this paper, and the accuracy of the model was verified by real vehicle test. By model simulation of the cornering braking process, different road adhesion coefficient such as 0.15, 0.3, 0.45, 0.6, 0.75 was chosen to analyzed the changing curve of braking distance, articulation angle, yaw rate and lateral acceleration when initial speed of tractor-semitrailer was 30km h. The result showed that the peak values of articulation angle, yaw rate and lateral acceleration gotten by simulation were the largest. On the road of road adhesion coefficient 0.15, distance of tractor-semitrailer cornering braking was the longest. On the road of road adhesion coefficient 0.75, distance of tractor-semitrailer cornering braking was the shortest and the peak values of articulation angle, yaw rate and lateral acceleration were small relatively.

  5. Investigation of Friction Behaviors of Brake Shoe Materials using Metallic Filler

    Directory of Open Access Journals (Sweden)

    E. Surojo

    2015-12-01

    Full Text Available Some vehicles use brake shoe made from semi-metallic materials. Semi-metallic brake shoes are made from a combination of metallic and non-metallic materials. Metallic particles are added in the formulation of brake shoe material to improve composites characteristics. In this paper, friction behaviors of brake shoe material using metallic filler were investigated. Machining chips of cast iron and copper wire of electric motor used were incorporated in composite as metallic fillers with amount 0, 2, and 4 vol. %. Friction testing was performed to measure coefficient of friction by pressing surface specimen against the surface of rotating disc. The results show that cast iron chip and Cu short wire have effect on increasing coefficient of friction of brake shoe material. They form contact plateau at contact surface. At contact surface, the Cu short wires which have parallel orientation to the sliding contact were susceptible to detach from the matrix.

  6. Design of the Electronic Brake Pressure Modulator Using a Direct Adaptive Fuzzy Controller in Commercial Vehicles for the Safety of Braking in Fail

    Science.gov (United States)

    Kim, Hunmo

    In the brake systems, it is important to reduce the rear brake pressure in order to secure the safety of the vehicle in braking. So, there was some research that reduced and controlled the rear brake pressure exactly like a L. S. P. V and a E. L. S. P. V. However, the previous research has some weaknesses: the L. S. P. V is a mechanical system and its brake efficiency is lower than the efficiency of E. L. S. P. V. But, the cost of E. L. S. P. V is very higher so its application to the vehicle is very difficult. Additionally, when a fail appears in the circuit which controls the valves, the fail results in some wrong operation of the valves. But, the previous researchers didn't take the effect of fail into account. Hence, the efficiency of them is low and the safety of the vehicle is not confirmed. So, in this paper we develop a new economical pressure modulator that exactly controls brake pressure and confirms the safety of the vehicle in any case using a direct adaptive fuzzy controller.

  7. Development of fly ash-based automotive brake lining

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, S.; Chugh, Y.P. [South Illinois University, Carbondale, IL (United States). College of Engineering

    2007-07-15

    Coal-fired power plants all over the world generate huge amounts of fly ash each year, 70 million tons of which are produced in the United States alone. Only 40% of all fly ashes generated in the USA find beneficial applications and rest have to be disposed off, which is burden for the generation industry. Fly ash particles possess certain characteristics that make them suitable for use in friction composites as a filter material. An attempt has been made through this research to incorporate more than 50wt% of fly ash particles in automotive brake lining friction composites. This paper presents the research carried out on development of friction composites, using fly ash obtained from a specific power plant in Illinois. Ingredients such as phenolic resin, aramid pulp, glass fiber, potassium titanate, graphite, aluminum fiber and copper powder were used in the composite development phase, in addition to the fly ash. The developed brake lining composites have exhibited consistent coefficients of friction in the range of 0.35-0.4, and wear rates lower than 12wt%.

  8. A nonextensive view of the stellar braking indices

    Science.gov (United States)

    de Freitas, D. B.; Cavalcante, F. J.; Soares, B. B.; Silva, J. R. P.

    2015-08-01

    The present work is based on the effects of the magnetic braking for the angular-mometum loss evolution and, consequently, the relationship between stellar rotation and age. In general, this loss rate denoted by {d}J/{d}t depends on the angular velocity Ω in the form {d}J/ {d}t\\proptoΩq , where q is a parameter from nonextensive statistical mechanics. In the context of the stellar rotation, this parameter is directly related to the braking index. For q equal to unity, the scenario of the saturation of the magnetic field is recovered. Such an approach was proposed and investigated by de Freitas and De Medeiros for unsaturated field stars. We propose a new nonextensive approach for the stellar rotational evolution based on the Reiners and Mohanty model. We developed a nonextensive version of Reiners and Mohanty torque, and compare it with the model proposed in de Freitas and De Medeiros, by using a sample of velocity v\\sin i for ∼16000 field F- and G- stars. As a result, we show that the Kawaler and Reiners-Mohanty models exhibit strong discrepancies in relation to the domain of validity of the entropic index q. These discrepancies are mainly due to sensitivity on the stellar radius. Our results also showed that the modified Kawaler prescription is consistent in a wider mass ranges, while the Reiners and Mohanty model is restricted to masses less than from G6 stars.

  9. Big brake singularity is accommodated as an exotic quintessence field

    Science.gov (United States)

    Chimento, Luis P.; Richarte, Martín G.

    2016-02-01

    We describe a big brake singularity in terms of a modified Chaplygin gas equation of state p =(γm-1 )ρ +α γmρ-n, accommodate this late-time event as an exotic quintessence model obtained from an energy-momentum tensor, and focus on the cosmological behavior of the exotic field, its kinetic energy, and the potential energy. At the background level the exotic field does not blow up, whereas its kinetic energy and potential both grow without limit near the future singularity. We evaluate the classical stability of this background solution by examining the scalar perturbations of the metric along with the inclusion of entropy perturbation in the perturbed pressure. Within the Newtonian gauge, the gravitational field approaches a constant near the singularity plus additional regular terms. When the perturbed exotic field is associated with α >0 the perturbed pressure and contrast density both diverge, whereas the perturbed exotic field and the divergence of the exotic field's velocity go to zero exponentially. When the perturbed exotic field is associated with α <0 the contrast density always blows up, but the perturbed pressure can remain bounded. In addition, the perturbed exotic field and the divergence of the exotic field's velocity vanish near the big brake singularity. We also briefly look at the behavior of the intrinsic entropy perturbation near the singular event.

  10. Structure Analysis at the Micro Iron Pour at Gray Brake

    Directory of Open Access Journals (Sweden)

    Melya D. Sebayang

    2012-01-01

    Full Text Available The use of gray cast iron brake drum as the material is the most appropriate choice, because it has properties which have good heat conductivity, hardness, toughness, good friction properties and the ability to absorb vibration. The purpose of this study to determine the ratio of the microstructure on both original material drum that is new and original drum ex-wear. With the aim of analysis is expected to be used as basis in planning the development of better vehicle brakes. Of all the test results it can be mentioned chemical composition of test results with the main alloying elements, to drum new original: C 4:13%, 2:51% Si, 0.15% S, 0.65% Mn, 0.0054% P, and the original drum ex-wear: C 4:13%, 2:17% Si, 0.15% S, 0.53% Mn, 0.0054% P. So the comparison of properties of the resulting structure after the testing process on each drum is the hardness and resistance to wear and tear on a new original drum better when compared with the original drum ex-wear.

  11. Digital Sliding Mode Control of Anti-Lock Braking System

    Directory of Open Access Journals (Sweden)

    MITIC, D. B.

    2013-02-01

    Full Text Available The control of anti-lock braking system is a great challenge, because of the nonlinear and complex characteristics of braking dynamics, unknown parameters of vehicle environment and system parameter variations. Using some of robust control methods, such as sliding mode control, can be a right solution for these problems. In this paper, we introduce a novel approach to design of ABS controllers, which is based on digital sliding mode control with only input/output measurements. The relay term of the proposed digital sliding mode control is filtered through digital integrator, reducing the chattering phenomenon in that way, and the additional signal of estimated modelling error is introduced into control algorithm to enhance the system steady-state accuracy. The given solution was verified in real experimental framework and the obtained results were compared with the results of implementation of two other digital sliding mode control algorithms. It is shown that it gives better system response, higher steady-state accuracy and smaller chattering.

  12. A nonextensive view of the stellar braking indices

    CERN Document Server

    de Freitas, D B; Soares, B B; Silva, J R P

    2015-01-01

    The present work is based on a description for the angular mometum loss rate due to magnetic braking for main-sequence stars on the relationship between stellar rotation and age. In general, this loss rate denoted by $\\mathrm dJ/\\mathrm dt$ depends on angular velocity $\\Omega$ in the form $\\mathrm dJ/\\mathrm dt\\propto\\Omega^{q}$, where $q$ is a parameter extracted from nonextensive statistical mechanics. Already, in context of stellar rotation, this parameter is greater than unity and it is directly related to the braking index. For $q$ equal to unity, the scenario of saturation of the magnetic field is recovered, otherwise $q$ indicates an unsaturated field. This new approach have been proposed and investigated by de Freitas \\& De Medeiros for unsaturated field stars. In present work, we propose a nonextensive approach for the stellar rotational evolution based on the Reiners \\& Mohanthy model. In this sense, we developed a nonextensive version of Reiners \\& Mohanthy torque and also compare this ...

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

    Science.gov (United States)

    Wurster, James; Price, Daniel J.; Bate, Matthew R.

    2016-03-01

    We investigate whether or not the low ionization 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 ionization chemistry assuming 0.1 μm 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 13 au can form even in strong magnetic when all three non-ideal terms are present, and a disc of 38 au can form when only the Hall effect is present; in both cases, a counter-rotating envelope forms around the first hydrostatic core. For weaker, anti-aligned fields, the Hall effect produces massive discs comparable to those produced in the absence of magnetic fields, suggesting that planet formation via gravitational instability may depend on the sign of the magnetic field in the precursor molecular cloud core.

  14. Zavorne ploščice iz karboniziranega materiala za zavorne diske iz C/C-SiC: Carbonised-material-based brake pads for a C/C-SiC composite brake disc:

    OpenAIRE

    Stadler, Zmago

    2001-01-01

    Letely the brake discs from carbon-fibre-reinforced carbon composites infiltrated by silicon (LSI-process) have become very interesting for automotive brakes applications. Composite materials with a hard SiC layer on the surface of the disc (C/C-SiC) or composites with the fibre-reinforced ceramic structure (C/SiC) need the right brake-lining materials. The results of our new-brake-lining-material investigation for C/C-SiC brake discs are presented. The influence of some particular additives ...

  15. Radiative Magnetic Reconnection in Astrophysics

    CERN Document Server

    Uzdensky, Dmitri A

    2015-01-01

    I review a new rapidly growing area of high-energy plasma astrophysics --- radiative magnetic reconnection, i.e., a reconnection regime where radiation reaction influences reconnection dynamics, energetics, and nonthermal particle acceleration. This influence be may be manifested via a number of astrophysically important radiative effects, such as radiation-reaction limits on particle acceleration, radiative cooling, radiative resistivity, braking of reconnection outflows by radiation drag, radiation pressure, viscosity, and even pair creation at highest energy densities. Self-consistent inclusion of these effects in magnetic reconnection theory and modeling calls for serious modifications to our overall theoretical approach to the problem. In addition, prompt reconnection-powered radiation often represents our only observational diagnostic tool for studying remote astrophysical systems; this underscores the importance of developing predictive modeling capabilities to connect the underlying physical condition...

  16. 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.

  17. Interactive design optimization of magnetorheological-brake actuators using the Taguchi method

    International Nuclear Information System (INIS)

    This research explored an optimization method that would automate the process of designing a magnetorheological (MR)-brake but still keep the designer in the loop. MR-brakes apply resistive torque by increasing the viscosity of an MR fluid inside the brake. This electronically controllable brake can provide a very large torque-to-volume ratio, which is very desirable for an actuator. However, the design process is quite complex and time consuming due to many parameters. In this paper, we adapted the popular Taguchi method, widely used in manufacturing, to the problem of designing a complex MR-brake. Unlike other existing methods, this approach can automatically identify the dominant parameters of the design, which reduces the search space and the time it takes to find the best possible design. While automating the search for a solution, it also lets the designer see the dominant parameters and make choices to investigate only their interactions with the design output. The new method was applied for re-designing MR-brakes. It reduced the design time from a week or two down to a few minutes. Also, usability experiments indicated significantly better brake designs by novice users

  18. Modeling of automotive drum brakes for squeal and parameter sensitivity analysis

    Science.gov (United States)

    Huang, Jinchun; Krousgrill, Charles M.; Bajaj, Anil K.

    2006-01-01

    Many fundamental studies have been conducted to explain the occurrence of squeal in disc and drum brake systems. The elimination of brake squeal, however, still remains a challenging area of research. Here, a numerical modeling approach is developed for investigating the onset of squeal in a drum brake system. The brake system model is based on the modal information extracted from finite element models for individual brake components. The component models of drum and shoes are coupled by the shoe lining material which is modeled as springs located at the centroids of discretized drum and shoe interface elements. The developed multi degree of freedom coupled brake system model is a linear non-self-adjoint system. Its vibrational characteristics are determined by a complex eigenvalue analysis. The study shows that both the frequency separation between two system modes due to static coupling and their associated mode shapes play an important role in mode merging. Mode merging and veering are identified as two important features of modes exhibiting strong interactions, and those modes are likely candidates that lead to coupled-mode instability. Techniques are developed for a parameter sensitivity analysis with respect to lining stiffness and the stiffness of the brake actuation system. The influence of lining friction coefficient on the propensity to squeal is also discussed.

  19. Why do the braking indices of pulsars span over more than 100 millions?

    CERN Document Server

    Zhang, Shuang-Nan

    2012-01-01

    Here we report that the observed braking indices of the 366 pulsars in the sample of Hobbs et al. (2012) span from about $-10^8$ to about $+10^8$ and are significantly correlated with their characteristic ages. Using the model of magnetic field evolution we developed previously (Zhang & Xie 2012) based on the same data, we derived an analytical expression of the braking index, which agrees with all the observed statistical properties of the braking indices of the pulsars in the sample of Hobbs et al. (2012). Our model is, however, incompatible to the previous interpretation that the magnetic field growth is responsible for the observed small values of braking indices ($<3$) of "baby" pulsars with characteristic ages of less than $2\\times 10^3$ yr. We find that the "instantaneous" braking index of a pulsar may be different from the "averaged" braking index obtained from fitting the data over a certain time span. The close match between our model predicted "instantaneous" braking indices and the observed...

  20. Experimental Method for Analyzing Friction Phenomenon Related to Drum Brake Squeal

    Directory of Open Access Journals (Sweden)

    J. GLIŠOVIĆ

    2010-12-01

    Full Text Available Automobile brakes have been intensively developed during past few decades, but the maximum motor’s power, that should amortized in vehicle brakes, has been significantly increased also. Most of the kinetic energy of the moving vehicles is transforming into heat through friction. But the small part of kinetic energy transforms into sound pressure and makes noise. Low frequency squeal of drum brakes is very intense and can lead to customers’ complain. The interaction between the brake system and the vehicle framework and suspension is often very substantial during occurrence of brake noise. Unfortunately, to solve this type of squeal problem is also difficult because of the large number of components involved. The other cause is attributed to self-excited vibration that is induced when the friction material has a negative slope in relation to the relative velocity. This paper illustrates an approach to experimental studies of drum brakes in road conditions in order to monitor changes in the coefficient of friction that can generate drum brake squeal at low frequencies.

  1. Position control optimization of aerodynamic brake device for high-speed trains

    Science.gov (United States)

    Zuo, Jianyong; Luo, Zhuojun; Chen, Zhongkai

    2014-03-01

    The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions—constant, linear, and quadratic—are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25.71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

  2. Detection of visually unrecognizable braking tracks using Laser-Induced Breakdown Spectroscopy, a feasibility study

    Science.gov (United States)

    Prochazka, David; Bilík, Martin; Prochazková, Petra; Brada, Michal; Klus, Jakub; Pořízka, Pavel; Novotný, Jan; Novotný, Karel; Ticová, Barbora; Bradáč, Albert; Semela, Marek; Kaiser, Jozef

    2016-04-01

    Identification of the position, length and mainly beginning of a braking track has proven to be essential for determination of causes of a road traffic accident. With the introduction of modern safety braking systems and assistance systems such as the Anti-lock Braking System (ABS) or Electronic Stability Control (ESC), the visual identification of braking tracks that has been used up until the present is proving to be rather complicated or even impossible. This paper focuses on identification of braking tracks using a spectrochemical analysis of the road surface. Laser-Induced Breakdown Spectroscopy (LIBS) was selected as a method suitable for fast in-situ element detection. In the course of detailed observations of braking tracks it was determined that they consist of small particles of tire treads that are caught in intrusions in the road surface. As regards detection of the "dust" resulting from wear and tear of tire treads in the environment, organic zinc was selected as the identification element in the past. The content of zinc in tire treads has been seen to differ with regard to various sources and tire types; however, the arithmetic mean and modus of these values are approximately 1% by weight. For in-situ measurements of actual braking tracks a mobile LIBS device equipped with a special module was used. Several measurements were performed for 3 different cars and tire types respectively which slowed down with full braking power. Moreover, the influence of different initial speed, vehicle mass and braking track length on detected signal is discussed here.

  3. Short term Braking Capability during Power Interruptions for Integrated Matrix Converter-Motor Drives

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    The new trend in Adjustable Speed Drives (ASD) is to integrate the inverter and the motor into a single unit in order to reduce the production cost, the commissioning time and the physical size of the equipment. This last issue becomes more important, making the matrix converter topology more...... engages or to perform more effective a combined braking.This paper proposes a new method to provide short-term braking capability during a power outage for matrix converters. A braking chopper is needed in the clamp circuit, which allows for a drastically reduction of the capacitor size. The power flow in...

  4. Optimization of a parity of brake forces of automobiles in view of a bias of road

    International Nuclear Information System (INIS)

    In clause it is shown a method optimization of brake of forces in view of a bias road it is established, that in mountain conditions of loss of coupling weight of automobiles than 2-3 times concerning flat conditions therma are more. The degree of use of coupling weight in result use of a regulator of brake forces very much increases also efficiency of brake systems such a kind of automobiles is provided with definition of optimum factor of coupling at which value of loss of coupling weight is provided minimal

  5. Compression Strength Testing for Automotive Brake Pads Used in Earthquake Energy Dampers

    Directory of Open Access Journals (Sweden)

    Dragoş Voiculescu

    2010-01-01

    Full Text Available In order to calibrate a friction damper which uses automotive brake pads it is necessary to determine the compression behaviour of the friction material. This paper summarizes the experimental results obtained for a set of automotive brake pads made in Romania. These results are useful in order to determine the slip load level in a seismic energy dissipation mechanism which uses this type of friction pads. The paper presents the experimental set up and the compression behaviour curves obtained for a set of four commercial brake pads. The testing was performed by the author as a part of his research work, using a hydraulic compression press.

  6. The emergency braking module for an electronic copilot design and first results

    Energy Technology Data Exchange (ETDEWEB)

    Ameling, C.; Kirchner, A. [Univ. of the Federal Armed Forces Hamburg (Germany). Dept. of Mechanical Engineering

    2000-07-01

    This paper deals with design and development of an emergency braking module for an electronic copilot (ECP). ECP is used within an autonomous vehicle as a partial redundant system for vehicle control. ECP receives the necessary information about the positions and relative velocities of obstacles from various sources such as laserscanner or vision sensors. In the current stage of development the emergency breaking module computes, whether an object collides with the front of the vehicle. If the time-to-collision falls below the braking capacity an emergency braking is triggered. Experimental results show the capabilities of the system. (orig.)

  7. Braking indices of pulsars obtained in the presence of an effective force

    CERN Document Server

    Magalhaes, N S; Frajuca, C

    2016-01-01

    Braking indices of pulsars present a scientific challenge as their theoretical calculation is still an open problem. In this paper we report results of a study regarding such calculation which adapts the canonical model (which admits that pulsars are rotating magnetic dipoles) basically by introducing a compensating component in the energy conservation equation of the system. This component would correspond to an effective force that varies with the first power of the tangential velocity of the pulsar's crust. We test the proposed model using data available and predict braking indices values for different stars. We comment on the high braking index recently measured of the pulsar J1640-4631.

  8. Atmospheric testing of wind turbine trailing edge aerodynamic brakes

    Energy Technology Data Exchange (ETDEWEB)

    Miller, L.S. [Wichita State Univ., KS (United States); Migliore, P.G. [National Renewable Energy Lab., Golden, CO (United States); Quandt, G.A.

    1997-12-31

    An experimental investigation was conducted using an instrumented horizontal-axis wind turbine that incorporated variable span trailing-edge aerodynamic brakes. A primary goal was to directly compare study results with (infinite-span) wind tunnel data and to provide information on how to account for device span effects during turbine design or analysis. Comprehensive measurements were utilized to define effective changes in the aerodynamic coefficients, as a function of angle of attack and control deflection, for three device spans and configurations. Differences in the lift and drag behavior are most pronounced near stall and for device spans of less than 15%. Drag performance is affected only minimally (<70%) for 15% or larger span devices. Interestingly, aerodynamic controls with characteristic vents or openings appear most affected by span reductions and three-dimensional flow.

  9. A laboratory activity on the eddy current brake

    International Nuclear Information System (INIS)

    The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and electromagnetic properties of the magnet on the magnetic drag force. This video-based experiment is ideal for the study of kinematic graphs and the application of Newton's laws. Video motion analysis software enables students to make precise measurements of the magnet's position at incremental times during its motion, thus allowing them to quantify electromagnetic induction phenomena. The equipment needed for this experiment and data collection software are present in most physics teaching laboratories or are inexpensive and available. (paper)

  10. Stop layer: a flow braking mechanism in space and support from a lab experiment

    Science.gov (United States)

    Haerendel, G.; Suttle, L.; Lebedev, S. V.; Swadling, G. F.; Hare, J. D.; Burdiak, G. C.; Bland, S. N.; Chittenden, J. P.; Kalmoni, N.; Frank, A.; Smith, R. A.; Suzuki-Vidal, F.

    2016-06-01

    The paper presents short summaries and a synopsis of two completely independent discoveries of a fast flow braking process, one realized by a laboratory experiment (Lebedev et al 2014 Phys. Plasmas 21 056305), the other by theoretical reasoning stimulated by auroral observation (Haerendel 2015a J. Geophys. Res. Space Phys. 120 1697–714). The first has been described as a magnetically mediated sub-shock forming when a supersonic plasma flow meets a wall. The second tried to describe what happens when a high-beta plasma flow from the central magnetic tail meets the strong near-dipolar field of the magnetosphere. The term stop layer signals that flow momentum and energy are directly coupled to a magnetic perturbation field generated by a Hall current within a layer of the width of c/ω pi and immediately propagated out of the layer by kinetic Alfvén waves. As the laboratory situation is not completely collision-free, energy transfer from ions to electrons and subsequent radiative losses are likely to contribute. A synopsis of the two situations identifies and discusses six points of commonality between the two situations. It is pointed out that the stop layer mechanism can be regarded as a direct reversal of the reconnection process.

  11. EXPERIMENTAL DETERMINATION OF BRAKE THERMAL EFFICIENCY AND BRAKE SPECIFIC FUEL CONSUMPTION OF DIESEL ENGINE FUELLED WITH BIO-DIESEL

    Directory of Open Access Journals (Sweden)

    M. SHIVA SHANKAR

    2010-10-01

    Full Text Available The rapid depletion in world petroleum reserves and uncertainty in petroleum supply due to political and economical reasons, as well as, the sharp escalations in the petroleum prices have stimulated the search for alternatives to petroleum fuels. The situation is very grave in developing countries like India which imports 70% of the required fuel, spending 30% of her total foreign exchange earnings on oil imports. Petroleum fuels are being consumed by agriculture and transport sector for which diesel engine happens to be the prime mover. Diesel fuelled vehicles discharge significant amount of pollutants like CO, HC, NOx, soot, lead compounds which are harmful to the universe. Though there are wide varieties of alternative fuels available, the research has not yet provided the right renewable fuel to replace diesel. Vegetable oils due to their properties being close to diesel fuel may be a promising alternative for its use in diesel engines. The high viscosity and low volatility are the major drawbacks of the use of vegetable oils in diesel engines. India is the second largest cotton producing country in the world today. The cotton seeds are available in India at cheaper price. Experiments were conducted on 5.2 BHP single cylinder four stroke water-cooled variable compression diesel engine. Methyl ester of cottonseed oil is blended with the commercially available Xtramile diesel. Cottonseed oil methyl ester (CSOME is blended in four different compositions varying from 10% to 40% in steps of 10 vol%. Using these four blends and Xtramile diesel brake thermal efficiency (BTE and brake specific fuel consumption (BSFC are determined at 17.5 compression ratio.

  12. Design and control of a dual unidirectional brake hybrid actuation system for haptic devices.

    Science.gov (United States)

    Rossa, Carlos; Lozada, José; Micaelli, Alain

    2014-01-01

    Hybrid actuators combining brakes and motors have emerged as an efficient solution to achieve high performance in haptic devices. In this paper, an actuation approach using two unidirectional brakes and a DC motor is proposed. The brakes are coupled to overrunning clutches and can apply a torque in only one rotational direction. The associated control laws, that are independent of the virtual environment model, calculate the control gains in real time in order limit the energy and the stiffness delivered by the motor to ensure stability. The reference torque is respected using the combination of the motor and the brake. Finally, an user experiment has been performed to evaluate the influence of passive and active torque differences in the perception of elasticity. The proposed actuator has a torque range of 0.03 Nm to 5.5 Nm with a 17.75 kNm (-2) torque density. PMID:25122593

  13. ANALYSIS OF POSSIBILITY TO AVOID A RUNNING-DOW ACCIDENT TIMELY BRAKING

    Directory of Open Access Journals (Sweden)

    Sarayev, A.

    2013-06-01

    Full Text Available Such circumstances under which the drive can stop the vehicle by applying timely braking before reaching the pedestrian crossing or decrease the speed to the safe limit to avoid a running-down accident is considered.

  14. Morgan Brake National Wildlife Refuge Deer Harvest Records from 2011 Season

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These harvest data are from Morgan Brake during the 2011 deer season. They measure weight, antler size, prevalence of milk, and number of deer harvested.

  15. Mathews Brake National Wildlife Refuge public use review and development plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document addresses the ten Public Use Requirements for Mathews Brake National Wildlife Refuge as well as General Impressions of the review team.

  16. STUDY ON THE CONTROL SYSTEM OF HYDRAULIC MOMENT-ADJUSTED BRAKE FOR DOWNWARD BELT CONVEYOR

    Institute of Scientific and Technical Information of China (English)

    孟国营; 徐志强; 霍森; 方佳雨

    1997-01-01

    Having analyzed the drawbacks on the design of control system of hydraulic momentadjusted brake system, the author presents a closed loop control system in the process of start and braking of the conveyer. On the basis of the concept of the critical time and the critical acceleration and its deductions, the working mode of the conveyer can be identified and controlled in feedback, furthermore, thus realize the process of soft start. In the deceleration process, the author points out the problems that exist in the present control system and sets forward the control process that acted by the combined function of brake moment of motor and the drag torque of hydraulic brake at the beginning of deceleration, it will further improved reliability of conveyor system.

  17. Mathews Brake National Wildlife Refuge Deer Harvest Records from 2011 Season

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These harvest data are from Mathews Brake during the 2011 deer season. They measure weight, antler size, prevalence of milk, and number of deer harvested.

  18. Upper Ouachita and Handy Brake National Wildlife Refuge: Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan CCP was written to guide management on Upper Ouachita and Handy Brake NWRs for the next 15 years. This plan outlines the...

  19. Dynamic Analysis of a Floating Vertical Axis Wind Turbine Under Emergency Shutdown Using Hydrodynamic Brake

    DEFF Research Database (Denmark)

    Wang, K.; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    Emergency shutdown is always a challenge for an operating vertical axis wind turbine. A 5-MW vertical axis wind turbine with a Darrieus rotor mounted on a semi-submersible support structure was examined in this study. Coupled non-linear aero-hydro-servo-elastic simulations of the floating vertical...... axis wind turbine were carried out for emergency shutdown cases over a range of environmental conditions based on correlated wind and wave data. When generator failure happens, a brake should be applied to stop the acceleration of the rotor to prevent the rotor from overspeeding and subsequent disaster....... In addition to the traditional mechanical brake, a novel hydrodynamic brake was presented to apply to the shutdown case. The effects of the hydrodynamic brake on the platform motions and structural loads under normal operating conditions and during the emergency shutdown events were evaluated. The...

  20. The Comparative Analysis and Evaluation of Ecological Characteristics of Drum and Disk Wheel Brakes

    Directory of Open Access Journals (Sweden)

    Aleksandr Revin

    2011-04-01

    Full Text Available It is well-known that automobile transport as well as industry are the main sources of air pollution. In addition to exhaust gases, the flow of traffic releases a cloud of dust, consisting of over 60% of micro- and ultramicroscopic particles with radius of 10.0–0.25 µm, which are formed due to wheel abrasion (caused by the road grip of a tyre and the use of the brake blocks (in braking. The products formed in the process of wearing of the wheel brake pads are also the sources of the mass of fine dispersed particles over an urban highway. The authors analyse and evaluate ecological characteristics of drum and disk wheel brakes of vehicles.Article in Russian

  1. Mobile Acoustical Bat Monitoring Annual Summary Report CY 2012 to 2015 - Morgan Brake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These reports summarize bat calls collected along transects at Morgan Brake National Wildlife Refuge between 2012 and 2015. Calls were classified using Bat Call ID...

  2. Mobile Acoustical Bat Monitoring Annual Summary Report CY 2012 to 2015 - Mathews Brake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These reports summarize bat calls collected along transects at Mathews Brake National Wildlife Refuge between 2012 and 2015. Calls were classified using Bat Call ID...

  3. Development of an Engine Air-Brake for Quiet Drag Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A novel quiet engine air-brake (EAB) is proposed in response to NASA's solicitation for active and passive noise control concepts for conventional and advanced...

  4. An analysis of the friction mechanism on brake gear of railway rolling stock

    Directory of Open Access Journals (Sweden)

    J. H. Barnard

    1985-03-01

    Full Text Available Friction energy dissipation at an interface involves a wide range of interdisciplinary concepts. As the demand for higher operating speeds increased, the limitations of cast iron as the traditional friction material for rail transport brakes became more apparent. Only through an intensive analysis of the interfacial interaction between the brake block and brake path could the problems encountered with other promising friction materials be solved. The article deals with the difficulties pertaining to the early composite materials, and indicates how these were overcome by the understanding and implementation of new techniques not previously associated with conventional systems connected with railway braking. Two composite materials, that is 840/N for locomotives and freight wagons where mass oriented momentum dominates, and high friction composite 655/C for passenger vehicles with a predominantly speed-oriented momentum, are presently used.

  5. Environmental Assessment of the Proposed Opening of Mathews Brake National Wildlife Refuge to Fishing

    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...

  6. Development of an Engine Air-Brake for Quiet Drag Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A novel quiet engine air-brake is proposed in response to NASA's solicitation for concepts for active and passive control of noise sources for conventional and...

  7. Laboratory testing of airborne brake wear particle emissions using a dynamometer system under urban city driving cycles

    Science.gov (United States)

    Hagino, Hiroyuki; Oyama, Motoaki; Sasaki, Sousuke

    2016-04-01

    To measure driving-distance-based mass emission factors for airborne brake wear particulate matter (PM; i.e., brake wear particles) related to the non-asbestos organic friction of brake assembly materials (pads and lining), and to characterize the components of brake wear particles, a brake wear dynamometer with a constant-volume sampling system was developed. Only a limited number of studies have investigated brake emissions under urban city driving cycles that correspond to the tailpipe emission test (i.e., JC08 or JE05 mode of Japanese tailpipe emission test cycles). The tests were performed using two passenger cars and one middle-class truck. The observed airborne brake wear particle emissions ranged from 0.04 to 1.4 mg/km/vehicle for PM10 (particles up to 10 μm (in size), and from 0.04 to 1.2 mg/km/vehicle for PM2.5. The proportion of brake wear debris emitted as airborne brake wear particles was 2-21% of the mass of wear. Oxygenated carbonaceous components were included in the airborne PM but not in the original friction material, which indicates that changes in carbon composition occurred during the abrasion process. Furthermore, this study identified the key tracers of brake wear particles (e.g., Fe, Cu, Ba, and Sb) at emission levels comparable to traffic-related atmospheric environments.

  8. Research of Testing Devices That Determine Friction Parameter and Wear Resistance of Brake Pads

    OpenAIRE

    Timur, Mustafa; Kılıç, Halil

    2013-01-01

    The testing devices used today handles the variables such as speed, temperature, pressure occuring in automobiles due to various factors, and examines the impacts of these variables on brake pads in automobiles. In these devices, following experimental studies, the friction paramters, erosion resistance and thermal contacts of brake pads can be easily determined. Although it is quite easy to obtain information about the states of the materials using test device, testing devices have provided ...

  9. Validity of Spontaneous Braking and Lane Changing with Scope of Awareness by Using Measured Traffic Flow

    OpenAIRE

    Kohei Arai; Steven Ray Sentinuwo

    2013-01-01

    This paper presents the validation method and its evaluation of the spontaneous braking and lane changing with scope awareness parameter. By using the real traffic flow data, the traffic cellular automaton model that accommodate these two driver behaviors, e.g., spontaneous braking and driver scope awareness has been compared and evaluated. The real traffic flow data have been observed via video-recording captured from real traffic situation. The validation results shown that by accommodate s...

  10. Rail temperature rise characteristics caused by linear eddy current brake of high-speed train

    OpenAIRE

    Xiaoshan Lu; Yunfeng Li; Mengling Wu; Jianyong Zuo; Wei Hu

    2014-01-01

    The rail temperature rises when the linear eddy current brake of high-speed train is working, which may lead to a change of rail physical characteristics or an effect on train operations. Therefore, a study concerning the characteristics of rail temperature rise caused by eddy current has its practical necessity. In the research, the working principle of a linear eddy current brake is introduced and its FEA model is established. According to the generation mechanism of eddy current, the theor...

  11. An approach of inertia compensation based on electromagnetic induction in brake test

    OpenAIRE

    Xiaowen Li; Han Que

    2016-01-01

    This paper briefly introduced the operational principle of the brake test bench, and points out the shortcomings when controlling the current of brake test, which means the reference measuring data is instantaneous. Aimed at this deficiency, a current control model based on electromagnetic induction and DC voltage is proposed. On the principle of electromagnetic induction, continuous data and automatic processes are realized. It significantly minimized errors owing to instantaneous data, and ...

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

    OpenAIRE

    Guo Lie; Ren Zejian; Ge Pingshu; Chang Jing

    2014-01-01

    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 cu...

  13. Magnetic Braking and Viscous Damping of Differential Rotation in Cylindrical Stars

    OpenAIRE

    Cook, James N.; Shapiro, Stuart L.; Stephens, Branson C.

    2003-01-01

    Differential rotation in stars generates toroidal magnetic fields whenever an initial seed poloidal field is present. The resulting magnetic stresses, along with viscosity, drive the star toward uniform rotation. This magnetic braking has important dynamical consequences in many astrophysical contexts. For example, merging binary neutron stars can form "hypermassive" remnants supported against collapse by differential rotation. The removal of this support by magnetic braking induces radial fl...

  14. Analysis of electrodynamic brake for utilization in systems with rotating shafts

    OpenAIRE

    Sokolov, Georgii

    2016-01-01

    The goal of this study was to conduct an analysis of an opportunity to apply eddy current brakes in dynamical systems containing rotating shafts. While conducting the research the general principles of deceleration, eddy currents’ origin, basics of magnetism and currently existing types of brakes were clarified and gathered briefly, but informatively. The theory which is explained in this thesis was taken from reliable secondary sources. The concepts of physics were investigated from sever...

  15. On a Flywheel-Based Regenerative Braking System for Regenerative Energy Recovery

    OpenAIRE

    Hsu, Tai-Ran

    2013-01-01

    This paper presents a unique flywheel-based regenerative energy recovery, storage and release system developed at the author's laboratory. It can recover and store regenerative energy produced by braking a motion generator with intermittent rotary velocity such as the rotor of a wind turbogenerator subject to intermittent intake wind and the axels of electric and hybrid gas-electric vehicles during frequent coasting and braking. Releasing of the stored regenerative energy in the flywheel is c...

  16. Physico-chemical characterization and oxidative reactivity evaluation of aged brake wear particles

    OpenAIRE

    Zhao Jiayuan; Lewinski Nastassja; Riediker Michael

    2015-01-01

    Brake wear dust is a significant component of traffic emissions and has been linked to adverse health effects. Previous research found a strong oxidative stress response in cells exposed to freshly generated brake wear dust. We characterized aged dust collected from passenger vehicles, using microscopy and elemental analyses. Reactive oxygen species (ROS) generation was measured with acellular and cellular assays using 2′7-dichlorodihydrofluorescein dye. Microscopy analyses revealed sam...

  17. Wear, friction, and temperature characteristics of an aircraft tire undergoing braking and cornering

    Science.gov (United States)

    Mccarty, J. L.; Yager, T. J.; Riccitiello, S. R.

    1979-01-01

    An investigation to evaluate the wear, friction, and temperature characteristics of aircraft tire treads fabricated from different elastomers is presented. The braking and cornering tests performed on aircraft tires retreaded with currently employed and experimental elastomers are described. The tread wear rate is discussed in relation to the slip ratio during braking and yaw angle during cornering. The extent of wear in either operational mode is examined in relation to the runway surface.

  18. Casting of Brake Disc and Impeller from Aluminium Scrap Using Silica Sand

    OpenAIRE

    Oladeji A. OGUNWOLE; Oluwafemi A. OLUGBOJI; Matthew S. ABOLARIN

    2007-01-01

    The impeller blade and the brake disc were produced using sand casting method. Wooden patterns of the two castings were constructed incorporating the necessary allowances. Green and moulding technique utilizing locally available materials were used for preparing the moulds. Aluminium scraps were used as the casting material. Melting of the Aluminium scraps was obtained using a crucible furnace and finally pouring the molten metal into the sand mould to obtain the impeller and the brake disc.A...

  19. Driver head displacement during (automatic) vehicle braking tests with varying levels of distraction

    OpenAIRE

    Rooij, L. van; Pauwelussen, J.; Camp, O.M.G.C. op den; Janssen, J. M.

    2013-01-01

    Vehicle occupant behavior in emergency driving conditions has a large effect on traffic safety. Distraction is estimated to be the cause of 15-20% of all crashes. Additionally, the posture of the occupants prior to the possibly unavoidable crash is known to have a large effect on the injury reducing performance of the restraint system. In this study it is investigated whether braking settings as well as driver distraction influence the kinematic response of an occupant during braking events, ...

  20. 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

  1. The Influence of Swirl Brakes on the Rotordynamic Forces Generated by Discharge-to-Suction Leakage Flows in Centrifugal Pumps

    OpenAIRE

    Sivo, Joseph M.; Allan J. Acosta; Brennen, Christopher E.; Caughey, Thomas K.

    1995-01-01

    Increasing interest has been given to swirl brakes as a means of reducing destabilizing rotordynamic forces due to leakage flows in new high speed rocket turbopumps. Although swirl brakes have been used successfully in practice (such as with the Space Shuttle HPOTP), no experimental tests until now have been performed to demonstrate their beneficial effect over a range of leakage flow rates. The present study investigates the effect of swirl brakes on rotordynamic forces generated by discha...

  2. Effect of coordination of optimal reclosing and fuzzy controlled braking resistor on transient stability during unsuccessful reclosing

    OpenAIRE

    Ali, Mohd.Hasan; Murata, Toshiaki; Tamura, Junji

    2006-01-01

    This paper analyzes the effect of the coordination of optimal reclosing and fuzzy logic-controlled braking resistor on the transient stability of a multimachine power system in case of an unsuccessful reclosing of circuit breakers. The transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is compared to that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor. The effectiveness of t...

  3. Big brake singularity is accommodated as an exotic quintessence field

    CERN Document Server

    Chimento, Luis P

    2015-01-01

    We describe a big brake singularity in terms of a modified Chaplygin gas equation of state $p=(\\ga_{m}-1)\\rho+\\al\\ga_{m}\\rho^{-n}$, accommodate this late-time event as an exotic quintessence model obtained from an energy-momentum tensor, and focus on the cosmological behaviour of the exotic field, its kinetic energy and the potential energy. At background level, the exotic field does not blow-up whereas its kinetic energy and potential both grow without limit near the future singularity. We evaluate the classical stability of this background solution by examining the scalar perturbations of the metric along with the inclusion of entropy perturbation in the perturbed pressure. Within the Newtonian gauge, the gravitational field approaches to a constant near the singularity plus additional regular terms. When the perturbed exotic field is associated with $\\al>0$, the perturbed pressure and contrast density both diverge whereas the perturbed exotic field and the divergence of exotic field's velocity go to zero e...

  4. Friction and wear behavior of carbon fiber reinforced brake materials

    Institute of Scientific and Technical Information of China (English)

    Du-qing CHENG; Xue-tao WANG; Jian ZHU; Dong-bua QIU; Xiu-wei CHENG; Qing-feng GUAN

    2009-01-01

    A new composite brake material was fabri-cated with metallic powders, barium sulphate and modified phenolic resin as the matrix and carbon fiber as the reinforced material. The friction, wear and fade character-istics of this composite were determined using a D-MS friction material testing machine. The surface structure of carbon fiber reinforced friction materials was analyzed by scanning electronic microscopy (SEM). Glass fiber-reinforced and asbestos fiber-reinforced composites with the same matrix were also fabricated for comparison. The carbon fiber-reinforced friction materials (CFRFM) shows lower wear rate than those of glass fiber- and asbestos fiber-reinforced composites in the temperature range of 100℃-300℃. It is interesting that the frictional coefficient of the carbon fiber-reinforced friction materials increases as frictional temperature increases from 100℃ to 300℃, while the frictional coefficients of the other two composites decrease during the increasing temperatures. Based on the SEM observation, the wear mechanism of CFRFM at low temperatures included fiber thinning and pull-out. At high temperature, the phenolic matrix was degraded and more pull-out enhanced fiber was demonstrated. The properties of carbon fiber may be the main reason that the CFRFM possess excellent tribological performances.

  5. Line short circuit detection by d.c. motor vehicles with regenerative braking equipment; Streckenkurzschlusserkennung in rueckspeisenden Gleichstromtriebfahrzeugen

    Energy Technology Data Exchange (ETDEWEB)

    Loesel, T.; Roehling, S. [elbas Elektrische Bahnsysteme Ingenieurgesellschaft mbH, Dresden (Germany)

    1996-12-31

    Line short circuits which occur during regenerative braking of traction vehicles cannot be detected reliably by conventional d.c. substation equipment. A method will be described how braking d.c. traction vehicles can detect a line short circuit and as a consequence interrupt regenerative braking. Unnecessary triggering can be detected and braking restored. Design and experiences will be presented. (orig.) [Deutsch] Die Erkennung von Streckenkurzschluessen, die waehrend des Einsatzes der Netzbremse auftreten, ist im Unterwerk nicht immer moeglich. Es wird ein Verfahren beschrieben, mit dem das bremsende Fahrzeug einen Kurzschluss selbst erkennt und die Netzbremsung daraufhin unterbricht. Das Verfahren kann Fehlausloesungen feststellen und zuruecknehmen. (orig.)

  6. Inclination angle and braking index evolution of pulsars with plasma-filled magnetosphere: application to high braking index of PSR J1640-4631

    CERN Document Server

    Ekşi, Kazım Yavuz; Çıkıntoğlu, Sercan; Gügercinoğlu, Erbil; Motlagh, Armin Vahdat; Kızıltan, Bülent

    2016-01-01

    The recently discovered rotationally powered pulsar PSR J1640-4631 is the first to have a braking index measured, with high enough precision, to be greater than three. An inclined magnetic rotator in vacuum or plasma would be subject to not only spin-down torque but also to an alignment torque. The vacuum model can address the braking index only for an almost orthogonal rotator which is incompatible with the single peaked pulse profile. We show that the magnetic dipole model with the corotating plasma predicts braking indices between $3-3.25$ and can explain the braking index of $3.15$ for two different inclination angles, $18.5\\pm 3$ degrees and $56 \\pm 4$ degrees. Of these the former is preferred given the pulse profile has a single peak. We infer the change in the inclination angle to be at the rate $-0.23$ degrees per century, three times smaller in absolute value than the rate recently observed from the Crab pulsar.

  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. Detection of braking intention in diverse situations during simulated driving based on EEG feature combination

    Science.gov (United States)

    Kim, Il-Hwa; Kim, Jeong-Woo; Haufe, Stefan; Lee, Seong-Whan

    2015-02-01

    Objective. We developed a simulated driving environment for studying neural correlates of emergency braking in diversified driving situations. We further investigated to what extent these neural correlates can be used to detect a participant's braking intention prior to the behavioral response. Approach. We measured electroencephalographic (EEG) and electromyographic signals during simulated driving. Fifteen participants drove a virtual vehicle and were exposed to several kinds of traffic situations in a simulator system, while EEG signals were measured. After that, we extracted characteristic features to categorize whether the driver intended to brake or not. Main results. Our system shows excellent detection performance in a broad range of possible emergency situations. In particular, we were able to distinguish three different kinds of emergency situations (sudden stop of a preceding vehicle, sudden cutting-in of a vehicle from the side and unexpected appearance of a pedestrian) from non-emergency (soft) braking situations, as well as from situations in which no braking was required, but the sensory stimulation was similar to stimulations inducing an emergency situation (e.g., the sudden stop of a vehicle on a neighboring lane). Significance. We proposed a novel feature combination comprising movement-related potentials such as the readiness potential, event-related desynchronization features besides the event-related potentials (ERP) features used in a previous study. The performance of predicting braking intention based on our proposed feature combination was superior compared to using only ERP features. Our study suggests that emergency situations are characterized by specific neural patterns of sensory perception and processing, as well as motor preparation and execution, which can be utilized by neurotechnology based braking assistance systems.

  9. New regenerative braking control strategy for rear-driven electrified minivans

    International Nuclear Information System (INIS)

    Highlights: • A regenerative braking system is designed for a rear-driven electric minivan. • A new control strategy coordinating energy efficiency and braking feel is proposed. • The control strategy is verified by simulation and hardware-in-loop (HIL) tests. • The proposed control strategy offers higher regeneration efficiency. - Abstract: As of to 2012, minivan ownership stood at 20 million units in China, accounting for 16% of the passenger car market. In this article, comprehensive research is carried out on the design and control of a regenerative braking system for a rear-driven electrified minivan. For improving the regeneration efficiency by as much as possible, a new regenerative braking control strategy called “modified control strategy” is proposed. Additionally, a control strategy called “baseline control strategy” is introduced as a comparative control strategy. Simulations and hardware-in-loop (HIL) tests are carried out. The results of the simulations and the HIL tests show that the modified control strategy offers considerably higher regeneration efficiency than the baseline control strategy. In normal deceleration braking, the regeneration efficiency of the modified control strategy reaches 47%, 15% higher than that of the baseline control strategy. In addition, improvement in the fuel economy of electric vehicles operating on the ECE driving cycle and enhanced with the modified control strategy is greater than 10%, which is 3% higher than that with the baseline control strategy

  10. End effect braking force reduction in high-speed single-sided linear induction machine

    International Nuclear Information System (INIS)

    Highlights: ► A new analytical equation to model the end effect braking force of SLIM is derived. ► Equations for efficiency, power factor and output thrust are analytically derived. ► The effect of design variables on the performance of the motor is analyzed. ► An optimization method is employed to minimize the end effect braking force (EEBF). ► The results show that EEBF is minimized by appropriate selection of motor parameters. - Abstract: Linear induction motors have been widely employed in industry because of their simple structure and low construction cost. However, they suffer from low efficiency and power factor. In addition, existence of so called end effect influences their performance especially in high speeds. The end effect deteriorates the performance of the motor by producing braking force. So, in this paper, by using Duncan equivalent circuit model, a new analytical equation is proposed to model end effect braking force. Employing the proposed equation and considering all phenomena involved in the single-sided linear induction motor, a simple design procedure is presented and the effect of different design variables on the performance of the motor is analyzed. A multi-objective optimization method based on genetic algorithm is introduced to maximize efficiency and power factor, as well as to minimize the end effect braking force, simultaneously. Finally, to validate the optimization results, 2D finite element method is employed.

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

    International Nuclear Information System (INIS)

    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. (paper)

  12. Intelligent control for braking-induced longitudinal vibration responses of floating-type railway bridges

    International Nuclear Information System (INIS)

    This paper presents an intelligent control method and its engineering application in the control of braking-induced longitudinal vibration of floating-type railway bridges. Equations of motion for the controlled floating-type railway bridges have been established based on the analysis of the longitudinal vibration responses of floating-type railway bridges to train braking and axle-loads of moving trains. For engineering applications of the developed theory, a full-scale 500 kN smart magnetorheologic (MR) damper has been designed, fabricated and used to carry out experiments on the intelligent control of braking-induced longitudinal vibration. The procedure for using the developed intelligent method in conjunction with the full-scale 500 kN MR dampers has been proposed and used to control the longitudinal vibration responses of the deck of floating-type railway bridges induced by train braking and axle-loads of moving trains. This procedure has been applied to the longitudinal vibration control of the Tian Xingzhou highway and railway cable-stayed bridge over the Yangtze River in China. The simulated results have shown that the intelligent control system using the smart MR dampers can effectively control the longitudinal response of the floating-type railway bridge under excitations of braking and axle-loads of moving trains

  13. Brake Failure from Residual Magnetism in the Mars Exploration Rover Lander Petal Actuator

    Science.gov (United States)

    Jandura, Louise

    2004-01-01

    In January 2004, two Mars Exploration Rover spacecraft arrived at Mars. Each safely delivered an identical rover to the Martian surface in a tetrahedral lander encased in airbags. Upon landing, the airbags deflated and three Lander Petal Actuators opened the three deployable Lander side petals enabling the rover to exit the Lander. Approximately nine weeks prior to the scheduled launch of the first spacecraft, one of these mission-critical Lander Petal Actuators exhibited a brake stuck-open failure during its final flight stow at Kennedy Space Center. Residual magnetism was the definitive conclusion from the failure investigation. Although residual magnetism was recognized as an issue in the design, the lack of an appropriately specified lower bound on brake drop-out voltage inhibited the discovery of this problem earlier in the program. In addition, the brakes had more unit-to-unit variation in drop-out voltage than expected, likely due to a larger than expected variation in the magnetic properties of the 15-5 PH stainless steel brake plates. Failure analysis and subsequent rework of two other Lander Petal Actuators with marginal brakes was completed in three weeks, causing no impact to the launch date.

  14. Regenerative braking systems with torsional springs made of carbon nanotube yarn

    Science.gov (United States)

    Liu, S.; Martin, C.; Lashmore, D.; Schauer, M.; Livermore, C.

    2014-11-01

    The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems.

  15. Regenerative braking systems with torsional springs made of carbon nanotube yarn

    International Nuclear Information System (INIS)

    The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems

  16. Road Identification for Anti-Lock Brake Systems Equipped with Only Wheel Speed Sensors

    Institute of Scientific and Technical Information of China (English)

    吴卫东; 尹用山

    2001-01-01

    Anti-lock brake systems (ABS) are now widely used on motor vehicles. To reduce product cost andto use currently available technologies, standard ABS uses only wheel speed sensors to detect wheel angularvelocities, which is not enough to directly obtain wheel slip ratios needed by the control unit, but can be usedto calculate reference slip ratios with measured wheel angular velocities and the estimated vehicle speed.Therefore, the road friction coefficient, which determines the vehicle deceleration during severe braking, is animportant parameter in estimating vehicle speed. This paper analyzes wheel acceleration responses insimulations of severe braking on different road surfaces and selects a pair of specific points to identify thewheel acceleration curve for each operating condition, such as road surface, pedal-braking torque and wheelvertical load. It was found that the curve using the selected points for each road surface clearly differs fromthat of the other road surfaces. Therefore, different road surfaces can be distinguished with these selectedpoints which represent their corresponding road surfaces. The analysis assumes that only wheel speed sensorsare available as hardware and that the road cohesion condition can be determined in the initial part of thesevere braking process.``

  17. Magnetic Braking and Viscous Damping of Differential Rotation in Cylindrical Stars

    CERN Document Server

    Cook, J N; Stephens, B C; Cook, James N.; Shapiro, Stuart L.; Stephens, Branson C.

    2003-01-01

    Differential rotation in stars generates toroidal magnetic fields whenever an initial seed poloidal field is present. The resulting magnetic stresses, along with viscosity, drive the star toward uniform rotation. This magnetic braking has important dynamical consequences in many astrophysical contexts. For example, merging binary neutron stars can form "hypermassive" remnants supported against collapse by differential rotation. The removal of this support by magnetic braking induces radial fluid motion, which can lead to delayed collapse of the remnant to a black hole. We explore the effects of magnetic braking and viscosity on the structure of a differentially rotating, compressible star, generalizing our earlier calculations for incompressible configurations. The star is idealized as a differentially rotating, infinite cylinder supported initially by a polytropic equation of state. The gas is assumed to be infinitely conducting and our calculations are performed in Newtonian gravitation. Though highly ideal...

  18. A New, Low Braking Index For the LMC Pulsar B0540-69

    CERN Document Server

    Marshall, F E; Harding, A K; Martin, P; Smith, D A

    2016-01-01

    We report the results of a 16-month monitoring campaign using the Swift satellite of PSR B0540-69, a young pulsar in the Large Magellanic Cloud. Phase connection was maintained throughout the campaign so that a reliable ephemeris could be determined, and the length of the campaign is adequate to accurately determine the spin frequency and its first and second derivatives. The braking index is 0.031 +/- 0.013 (90% confidence), a value much lower than previously reported for B0540-69 and almost all other young pulsars. We use data from the extensive monitoring campaign with RXTE to show that timing noise is unlikely to significantly affect the measurement. This is the first measurement of the braking index in the pulsar's recently discovered high spin-down state. We discuss possible mechanisms for producing the low braking index.

  19. Analysis of the minimum swerving distance for the development of a motorcycle autonomous braking system.

    Science.gov (United States)

    Giovannini, Federico; Savino, Giovanni; Pierini, Marco; Baldanzini, Niccolò

    2013-10-01

    In the recent years the autonomous emergency brake (AEB) was introduced in the automotive field to mitigate the injury severity in case of unavoidable collisions. A crucial element for the activation of the AEB is to establish when the obstacle is no longer avoidable by lateral evasive maneuvers (swerving). In the present paper a model to compute the minimum swerving distance needed by a powered two-wheeler (PTW) to avoid the collision against a fixed obstacle, named last-second swerving model (Lsw), is proposed. The effectiveness of the model was investigated by an experimental campaign involving 12 volunteers riding a scooter equipped with a prototype autonomous emergency braking, named motorcycle autonomous emergency braking system (MAEB). The tests showed the performance of the model in evasive trajectory computation for different riding styles and fixed obstacles. PMID:23792616

  20. On the second derivatives of periods and braking indices in radio pulsars

    CERN Document Server

    Malov, I F

    2016-01-01

    The analysis of some braking mechanisms for neutron stars was carried out to determine the sign of the second derivative of the pulsar period. This quantity is the important parameter for calculations of the braking index n. It is shown that this derivative can be positive and lead to decreasing of n. It is necessary to correct the methods of calculations of n used this moment because they are based as a rule on the suggestion on the constancy of pulsar parameters (magnetic fields, angles between some axes and so on). The estimations of corrections to braking indices are obtained. It is shown that these corrections can be marked for pulsars with long periods and their small derivatives.

  1. Research on motor rotational speed measurement in regenerative braking system of electric vehicle

    Science.gov (United States)

    Pan, Chaofeng; Chen, Liao; Chen, Long; Jiang, Haobin; Li, Zhongxing; Wang, Shaohua

    2016-01-01

    Rotational speed signals acquisition and processing techniques are widely used in rotational machinery. In order to realized precise and real-time control of motor drive and regenerative braking process, rotational speed measurement techniques are needed in electric vehicles. Obtaining accurate motor rotational speed signal will contribute to the regenerative braking force control steadily and realized higher energy recovery rate. This paper aims to develop a method that provides instantaneous speed information in the form of motor rotation. It addresses principles of motor rotational speed measurement in the regenerative braking systems of electric vehicle firstly. The paper then presents ideal and actual Hall position sensor signals characteristics, the relation between the motor rotational speed and the Hall position sensor signals is revealed. Finally, Hall position sensor signals conditioning and processing circuit and program for motor rotational speed measurement have been carried out based on measurement error analysis.

  2. Observer Based Traction/Braking Control Design for High Speed Trains Considering Adhesion Nonlinearity

    Directory of Open Access Journals (Sweden)

    Wenchuan Cai

    2014-01-01

    Full Text Available Train traction/braking control, one of the key enabling technologies for automatic train operation, literally takes its action through adhesion force. However, adhesion coefficient of high speed train (HST is uncertain in general because it varies with wheel-rail surface condition and running speed; thus, it is extremely difficult to be measured, which makes traction/braking control design and implementation of HSTs greatly challenging. In this work, force observers are applied to estimate the adhesion force or/and the resistance, based on which simple traction/braking control schemes are established under the consideration of actual wheel-rail adhesion condition. It is shown that the proposed controllers have simple structure and can be easily implemented from real applications. Numerical simulation also validates the effectiveness of the proposed control scheme.

  3. Compliant mechanism road bicycle brake: a rigid-body replacement case study

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Brian M [Los Alamos National Laboratory; Howell, Larry L [NON LANL; Magleby, Spencer P [NON LANL

    2011-01-19

    The design of high-performance bicycle brakes is complicated by the competing design objectives of increased performance and low weight. But this challenge also provides a good case study to demonstrate the design of compliant mechanisms to replace current rigid-link mechanisms. This paper briefly reviews current road brake designs, demonstrates the use of rigid-body replacement synthesis to design a compliant mechanism, and illustrates the combination of compliant mechanism design tools. The resulting concept was generated from the modified dual-pivot brake design and is a partially compliant mechanism where one pin has the dual role of a joint and a mounting pin. The pseudo-rigid-body model, finite element analysis, and optimization algorithms are used to generate design dimensions, and designs are considered for both titanium and E-glass flexures. The resulting design has the potential of reducing the part count and overall weight while maintaining a performance similar to the benchmark.

  4. Casting of Brake Disc and Impeller from Aluminium Scrap Using Silica Sand

    Directory of Open Access Journals (Sweden)

    Oladeji A. OGUNWOLE

    2007-01-01

    Full Text Available The impeller blade and the brake disc were produced using sand casting method. Wooden patterns of the two castings were constructed incorporating the necessary allowances. Green and moulding technique utilizing locally available materials were used for preparing the moulds. Aluminium scraps were used as the casting material. Melting of the Aluminium scraps was obtained using a crucible furnace and finally pouring the molten metal into the sand mould to obtain the impeller and the brake disc.After fettling and cleaning, the two casting were found to be good. The casting yield was found to be 73.59% for the impeller blade and 85.1% for the brake disc which indicate that sound casting was achieved.

  5. Comparison of Regenerative Braking Efficiencies of MY2012 and MY2013 Nissan Leaf

    Directory of Open Access Journals (Sweden)

    Albert Boretti

    2016-07-01

    Full Text Available The use of kinetic energy recovery systems (KERS is the best solution presently available to dramatically improve the energy economy of passenger cars. The paper presents an experimental analysis of the energy flow to and from the battery of a MY 2012 and a MY 2013 Nissan Leaf covering the Urban Dynamometer Driving Schedule (UDDS. The two vehicles differ for the integration of the electric drivetrain component, plus a different use of the electric motor and the regenerative brakes, in addition to a different weight. It is shown that while the efficiency propulsive power to vehicle / power from battery are basically unchanged, at about 87-89 %, the efficiency power to the battery / braking power to vehicle are significantly improved from values of about 70-80 % to values of 72-87 %. The analysis provides a state-of-the-art benchmark of the propulsion and regenerative braking efficiencies of electric vehicles.

  6. Development of a net shape manufacturing method for ventilated brake discs in single piece design

    Energy Technology Data Exchange (ETDEWEB)

    Zuber, Ch.; Heidenreich, B. [German Aerospace Center (DLR) Institute of Structures and Design, Pfaffenwaldring 38-40, 70569, Stuttgart (Germany)

    2006-04-15

    Carbon fibre reinforced ceramic matrix composites (CMC), originally developed for lightweight heat shields of spacecraft, are used for high performance brake discs in sports cars from different manufacturers. In contrast to the CMC materials for space applications, based on woven fabrics and costly manufacturing methods, these low cost friction materials are produced by liquid silicon infiltration of porous Carbon/Carbon (C/C) preforms, based on short fibre reinforced CFRP green bodies manufactured via warm press technique. In this work, different manufacturing methods for ventilated CMC brake discs are compared to each other, and the development of a new technology for the manufacture of single piece C/C-SiC brake discs in net shape technique is presented. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  7. Brake performance of core–shell structured carbonyl iron/silica based magnetorheological suspension

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Phuong-Bac; Do, Xuan-Phu; Jeon, Juncheol; Choi, Seung-Bok [Smart Structures and Systems Laboratory, Department of Mechanical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Liu, Ying Dan [Department of Polymer Science and Engineering, Inha University, Incheon 402-751 (Korea, Republic of); State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Choi, Hyoung Jin, E-mail: hjchoi@inha.ac.kr [Department of Polymer Science and Engineering, Inha University, Incheon 402-751 (Korea, Republic of)

    2014-10-01

    Chemically stable core–shell structured magnetic particles were synthesized by coating soft-magnetic carbonyl iron (CI) microspheres with silica through a sol–gel reaction, and applied as magnetorheological (MR) materials for a specially designed small-sized MR brake. The dynamic yield stress of the MR suspension containing the synthesized particles was also measured using a rotational rheometer under an applied magnetic field. The performance characteristics of the MR brake, including field dependent torque, hysteresis, time and torque tracking control responses were examined. The results showed that with the exception of the settling time, the other response times were faster than those of the pristine CI based MR fluid. - Highlights: • Silica coated magnetic particle was fabricated as magnetorheological (MR) material. • Small-sized MR brake of disc-type was specially designed. • MR fluid based on silica coated particles exhibited improved tracking accuracy.

  8. Evaluation of the deposition, translocation and pathological response of brake dust with and without added chrysotile in comparison to crocidolite asbestos following short-term inhalation: Interim results

    International Nuclear Information System (INIS)

    Chrysotile has been frequently used in the past in manufacturing brakes and continues to be used in brakes in many countries. This study was designed to provide an understanding of the biokinetics and potential toxicology following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake dust or crocidolite asbestos. No significant pathological response was observed at any time point in either the brake dust or chrysotile/brake dust exposure groups. The long chrysotile fibers (> 20 μm) cleared quickly with T1/2 estimated as 30 and 33 days, respectively in the brake dust and the chrysotile/brake dust exposure groups. In contrast, the long crocidolite fibers had a T1/2 > 1000 days and initiated a rapid inflammatory response in the lung following exposure resulting in a 5-fold increase in fibrotic response within 91 days. These results provide support that brake dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung following short term inhalation. - Highlights: • We evaluated brake dust w/wo added chrysotile in comparison to crocidolite asbestos. • Persistence, translocation, pathological response in the lung and pleural cavity. • Chrysotile cleared rapidly from the lung while the crocidolite asbestos persisted. • No significant pathology observed at any time point in the brake-dust groups. • Crocidolite produced pathological response - Wagner 4 interstitial fibrosis by 32d

  9. Energy-Regenerative Braking Control of Electric Vehicles Using Three-Phase Brushless Direct-Current Motors

    Directory of Open Access Journals (Sweden)

    Bo Long

    2013-12-01

    Full Text Available Regenerative braking provides an effective way of extending the driving range of battery powered electric vehicles (EVs. This paper analyzes the equivalent power circuit and operation principles of an EV using regenerative braking control technology. During the braking period, the switching sequence of the power converter is controlled to inverse the output torque of the three-phase brushless direct-current (DC motor, so that the braking energy can be returned to the battery. Compared with the presented methods, this technology can achieve several goals: energy recovery, electric braking, ultra-quiet braking and extending the driving range. Merits and drawbacks of different braking control strategy are further elaborated. State-space model of the EVs under energy-regenerative braking operation is established, considering that parameter variations are unavoidable due to temperature change, measured error, un-modeled dynamics, external disturbance and time-varying system parameters, a sliding mode robust controller (SMRC is designed and implemented. Phase current and DC-link voltage are selected as the state variables, respectively. The corresponding control law is also provided. The proposed control scheme is compared with a conventional proportional-integral (PI controller. A laboratory EV for experiment is setup to verify the proposed scheme. Experimental results show that the drive range of EVs can be improved about 17% using the proposed controller with energy-regeneration control.

  10. Toxicity and mutagenicity of low-metallic automotive brake pad materials.

    Science.gov (United States)

    Malachova, Katerina; Kukutschova, Jana; Rybkova, Zuzana; Sezimova, Hana; Placha, Daniela; Cabanova, Kristina; Filip, Peter

    2016-09-01

    Organic friction materials are standardly used in brakes of small planes, railroad vehicles, trucks and passenger cars. The growing transportation sector requires a better understanding of the negative impact related to the release of potentially hazardous materials into the environment. This includes brakes which can release enormous quantities of wear particulates. This paper addresses in vitro detection of toxic and mutagenic potency of one model and two commercially available low-metallic automotive brake pads used in passenger cars sold in the EU market. The model pad made in the laboratory was also subjected to a standardized brake dynamometer test and the generated non-airborne wear particles were also investigated. Qualitative "organic composition" was determined by GC/MS screening of dichloromethane extracts. Acute toxicity and mutagenicity of four investigated sample types were assessed in vitro by bioluminescence assay using marine bacteria Vibrio fischeri and by two bacterial bioassays i) Ames test on Salmonella typhimurium His(-) and ii) SOS Chromotest using Escherichia coli PQ37 strain. Screening of organic composition revealed a high variety of organic compounds present in the initial brake pads and also in the generated non-airborne wear debris. Several detected compounds are classified by IARC as possibly carcinogenic to humans, e. g. benzene derivatives. Acute toxicity bioassay revealed a response of bacterial cells after exposure to all samples used. Phenolic resin and wear debris were found to be acutely toxic; however in term of mutagenicity the response was negative. All non-friction exposed brake pad samples (a model pad and two commercial pad samples) were mutagenic with metabolic activation in vitro. PMID:27179608

  11. A parametric FE modeling of brake for non-linear analysis

    OpenAIRE

    Ibrahim Ahmed, Yasser Fatouh, Wael Aly

    2014-01-01

    A parametric modeling of a drum brake based on 3-D Finite Element Methods (FEM) for non-contact analysis is presented. Many parameters are examined during this study such as the effect of drum-lining interface stiffness, coefficient of friction, and line pressure on the interface contact. Firstly, the modal analysis of the drum brake is also studied to get the natural frequency and instability of the drum to facilitate transforming the modal elements to non-contact elements. It is shown that ...

  12. Boric acid effect in phenolic composites on tribological properties in brake linings

    International Nuclear Information System (INIS)

    In the present work, using a pad-on-disc-type wear tester, the tribological properties of the pad next to the disk made of cast iron were investigated with changing the substance of the components. As well, micro-structural characterisation of braking pads was performed using scanning electron microscopy and also temperature outcome of the pads was examined at the temperatures of 50-400 oC in the pressure of 1050 and 3000 kPa. Finally, the effect of environment to the pads was studied in water, salty water, oil and braking liquid media

  13. 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

  14. Classical and quantum Big Brake cosmology for scalar field and tachyonic models

    OpenAIRE

    Kamenshchik, Alexander Y.; Manti, Serena

    2012-01-01

    We study a relation between the cosmological singularities in classical and quantum theory, comparing the classical and quantum dynamics in some models possessing the Big Brake singularity - the model based on a scalar field and two models based on a tachyon-pseudo-tachyon field . It is shown that the effect of quantum avoidance is absent for the soft singularities of the Big Brake type while it is present for the Big Bang and Big Crunch singularities. Thus, there is some kind of a classical ...

  15. Classical and quantum Big Brake cosmology for scalar field and tachyonic models

    OpenAIRE

    Kamenshchik, A.; Manti, S.

    2013-01-01

    We study a relation between the cosmological singularities in classical and quantum theory, comparing the classical and quantum dynamics in some models possessing the Big Brake singularity - the model based on a scalar field and two models based on a tachyon-pseudo-tachyon field . It is shown that the effect of quantum avoidance is absent for the soft singularities of the Big Brake type while it is present for the Big Bang and Big Crunch singularities. Thus, there is some kind of a classical ...

  16. Assessment and preliminary design of an energy buffer for regenerative braking in electric vehicles

    Science.gov (United States)

    Buchholz, R.; Mathur, A. K.

    1979-01-01

    Energy buffer systems, capable of storing the vehicle energy during braking and reusing this stored energy during acceleration, were examined. Some of these buffer systems when incorporated in an electric vehicle would result in an improvement in the performance and range under stop and go driving conditions. Buffer systems considered included flywheels, hydropneumatic, pneumatic, spring, and regenerative braking. Buffer ranking and rating criteria were established. Buffer systems were rated based on predicted range improvements, consumer acceptance, driveability, safety, reliability and durability, and initial and life cycle costs. A hydropneumatic buffer system was selected.

  17. 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.

  18. A new strategy for transient stability using augmented generator control and local dynamic braking

    Energy Technology Data Exchange (ETDEWEB)

    Dorsey, J.; Jiang, H.; Habetler, T. [Georgia Inst. of Tech., Atlanta, GA (United States); Qu, Z. [University of Central Florida, Orlando, FL (United States)

    1994-12-31

    A decentralized automatic control strategy for significantly improving the transient stability of a large power system is introduced. The strategy combines local dynamic braking and a straightforward augmentation of the existing turbine / governor control system that uses only local feedback. The brake resistor, which employs thick film, metal oxide technology, has no inductance and is of very low resistance, allowing its use during fault to show a generator`s acceleration. Simulation results using the 39 Bus New England system show that the strategy dramatically increases the global stability of a power system. (author) 15 refs., 7 figs., 1 tab.

  19. Control strategy for electro-mechanical braking based on curves of ECE regulations and ideal braking force%基于ECE法规和Ⅰ曲线的机电复合制动控制策略

    Institute of Scientific and Technical Information of China (English)

    刘丽君; 姬芬竹; 杨世春; 徐斌

    2013-01-01

    具有再生制动功能的电动汽车制动系统与传统燃油汽车的摩擦制动系统不同,在回收部分制动能量的同时其制动稳定性会发生变化.在保证安全制动距离的前提下,制动能量回收率的提高受到制动稳定性的制约和限制.针对电制动和常规摩擦制动组成的机电复合制动系统,建立了电制动力、电制动力矩和电池充电功率计算模型.考虑到电机转矩特性和电池充电功率限制,以最大化回收制动能量为目标,设计3种不同的机电复合制动控制策略.通过在ADVISOR软件中建立嵌入式仿真模块对制动能量回收率、电池荷电状态和纯电动模式的续驶里程进行了仿真计算和分析.计算结果表明:Ⅰ曲线和ECE(Economic Commissionof Europe safety regulations)法规边界线都不是理想的制动力分配曲线,所提出的制动力分配曲线OABCD综合性能较好,制动能量回收率达到59.56%,且一个循环的荷电状态变化很小,仅降低了4.29%.实车试验表明能量回收能够提高续驶里程.%The braking system of electric vehicle with regenerative braking is different from friction braking system of conventional fuel vehicle. Regenerative braking system makes braking stability of electric vehicles change when it recovers braking energy of vehicles. The improvement of braking energy recovery ration was restricted by the braking stability under the precondition of safe braking distance. Aiming at the electromechanical hybrid braking system composed of electric braking and conventional friction braking, the calculation models of electric braking force, electric braking torque and battery charging power were established. In view of the motor torque characteristics and battery charging power limit, three kinds of control strategies for e-lectro-mechanical hybrid braking were designed for recovering the maximal braking energy. The baking energy recovery ration, state of charge and driving range in

  20. Coordinated vehicle traction control based on engine torque and brake pressure under complicated road conditions

    Science.gov (United States)

    Kang, Mingxin; Li, Liang; Li, Hongzhi; Song, Jian; Han, Zongqi

    2012-09-01

    Vehicle traction control system has been developed to enhance the traction capability and the direction stability of the driving wheels through the tyre slip ratio regulation. Under normal situations, if the tyre slip ratio exceeds a certain threshold, the slip ratio of the driving wheel is regulated by the coupled interaction of the engine torque and the active brake pressure. In order to obtain the best driving performance on a road under complicated friction conditions, the driving torque and the active brake pressure, need to be decoupled and adjusted to avoid penalisation of each other. In this paper, a coordinated cascade control method with two sliding-mode variable structure controllers is presented. In this control method, the driving wheel slip ratio is regulated by adjusting the engine torque and the wheel brake pressure. Through the sliding-mode controller, the engine torque is tuned to achieve the maximum driving acceleration and then the active brake pressure is applied to the slipped wheel for further modification of the wheel slip ratio. The advantage of this control method is that through proper regulation, the conflict between the two control inputs could be avoided. Finally, the simulation results validate the effectiveness of the proposed method.

  1. BRAKING PRECISION, THE CAR NUMBER IN THE TRAILER AND THE HUMP''S PERFORMANCE

    Directory of Open Access Journals (Sweden)

    V. V. Zhuravel

    2009-06-01

    Full Text Available A form of regression equations is determined, which adequately describe a correlation between the error of braking of cuts and the average speed of their collision on hump tracks, the average length of «window» and the average quantity of setting operations per processed wagon taking into account an influence of quantity of wagons in a cut.

  2. On Airborne Nano/Micro-Sized Particles Released from Low-Metallic Automotive Brakes

    Czech Academy of Sciences Publication Activity Database

    Kukutschová, J.; Moravec, Pavel; Tomášek, V.; Matějka, V.; Smolík, Jiří; Schwarz, Jaroslav; Seidlerová, J.; Šafářová, K.; Filip, P.

    2011-01-01

    Roč. 159, č. 4 (2011), s. 998-1006. ISSN 0269-7491 Institutional research plan: CEZ:AV0Z40720504 Keywords : brake wear debris * nano particles * oxidative wear Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.746, year: 2011

  3. 49 CFR 393.47 - Brake actuators, slack adjusters, linings/pads and drums/rotors.

    Science.gov (United States)

    2010-10-01

    ... drums/rotors. 393.47 Section 393.47 Transportation Other Regulations Relating to Transportation..., slack adjusters, linings/pads and drums/rotors. (a) General requirements. Brake components must be... on the lining shall not exceed 1.6 mm (1/16 inch). (g) Drums and rotors. The thickness of the...

  4. Asymmetric Barrier Lyapunov Function-Based Wheel Slip Control for Antilock Braking System

    Directory of Open Access Journals (Sweden)

    Xiaolei Chen

    2015-01-01

    Full Text Available As an important device of the aircraft landing system, the antilock braking system (ABS has a function to avoid aircraft wheels self-locking. To deal with the strong nonlinear characteristics, complex nonlinear control schemes are applied in ABS. However, none of existing control schemes focus on the braking operating status, which directly reflects wheels self-locking degree. In this paper, the braking operating status region is divided into three regions: the healthy region, the light slip region, and the deep slip region. An ABLF-based wheel slip controller is proposed for ABS to constrain the braking system operating status in the healthy region and the light slip region. Therefore the ABS will be prevented from operating in the deep slip region. Under the proposed control scheme, self-locking is avoided completely and zero steady state error tracking of the wheel optimal slip ratio is implemented. The Hardware-In-Loop (HIL experiments have validated the effectiveness of the proposed controller.

  5. 49 CFR 571.122 - Standard No. 122; Motorcycle brake systems.

    Science.gov (United States)

    2010-10-01

    ... fluid as specified in 49 CFR 571.116, e.g., DOT 3.) The lettering shall be: (a) Permanently affixed... authority at 49 CFR 1.50 and 49 CFR 501.8) ... 49 Transportation 6 2010-10-01 2010-10-01 false Standard No. 122; Motorcycle brake systems....

  6. Tribological characteristics of C/C-SiC braking composites under dry and wet conditions

    Institute of Scientific and Technical Information of China (English)

    LI Zhuan; XIAO Peng; XIONG Xiang; ZHU Su-hua

    2008-01-01

    C/C-SiC braking composites, based on reinforcement of carbon fibers and rnatrices of carbon and silicon carbide, were fabricated by warm compaction and in situ reaction process. The tribological characteristics of C/C-SiC braking composites under dry and wet conditions were investigated by means of MM-1000 type of friction testing machine. The influence of dry and wet conditions on the tribological characteristics of the C/C-SiC composites was ascertained. Under dry condition, C/C-SiC braking composites show superior tribological characteristics, including high coefficient of friction (0.38), good abrasive resistance (thickness loss is 1.10 μm per cycle) and steady breaking. The main wear mechanism is plastic deformation and abrasion caused by plough. Under wet condition, frictional films form on the worn surface. The coefficient of friction (0.35) could maintain mostly, and the thickness loss (0.70 μm per cycle) reduces to a certain extent. Furthermore, braking curves are steady and adhesion and oxidation are the main wear mechanisms.

  7. Particle Acceleration in Collapsing Magnetic Traps with a Braking Plasma Jet

    Science.gov (United States)

    Borissov, Alexei; Neukirch, Thomas; Threlfall, James

    2016-05-01

    Collapsing magnetic traps (CMTs) are one proposed mechanism for generating non-thermal particle populations in solar flares. CMTs occur if an initially stretched magnetic field structure relaxes rapidly into a lower-energy configuration, which is believed to happen as a by-product of magnetic reconnection. A similar mechanism for energising particles has also been found to operate in the Earth's magnetotail. One particular feature proposed to be of importance for particle acceleration in the magnetotail is that of a braking plasma jet, i.e. a localised region of strong flow encountering stronger magnetic field which causes the jet to slow down and stop. Such a feature has not been included in previously proposed analytical models of CMTs for solar flares. In this work we incorporate a braking plasma jet into a well studied CMT model for the first time. We present results of test particle calculations in this new CMT model. We observe and characterise new types of particle behaviour caused by the magnetic structure of the jet braking region, which allows electrons to be trapped both in the braking jet region and the loop legs. We compare and contrast the behaviour of particle orbits for various parameter regimes of the underlying trap by examining particle trajectories, energy gains and the frequency with which different types of particle orbit are found for each parameter regime.

  8. 78 FR 21189 - Agency Requests for Approval of a New Information Collection: Motor Vehicle Brake Fluids

    Science.gov (United States)

    2013-04-09

    ..., Washington, DC, 20590. SUPPLEMENTARY INFORMATION: OMB Control Number: 2127-0521 Title: 49 CFR 571.116, Motor... performance and design requirements for motor vehicle brake fluids and hydraulic system mineral oils. Section... packagers of hydraulic system mineral oils. The information on the label of a container of motor...

  9. Detection of brake wear aerosols by aerosol time-of-flight mass spectrometry

    Science.gov (United States)

    Beddows, D. C. S.; Dall'Osto, M.; Olatunbosun, O. A.; Harrison, Roy M.

    2016-03-01

    Brake dust particles were characterised using an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) operated using two inlet configurations, namely the aerodynamic lens (AFL) inlet and countersunk nozzle inlet. Laboratory studies show that dust particles are characterised by mass spectra containing ions deriving from Fe and Ba and although highly correlated to each other, the Fe and Ba signals were mostly detected using the nozzle inlet with relatively high laser desorption energies. When using the AFL, only [56Fe] and [-88FeO2] ions were observed in brake dust spectra generated using lower laser desorption pulse energies, and only above 0.75 mJ was the [138Ba] ion detected. When used with the preferred nozzle inlet configuration, the [-88FeO2] peak was considered to be the more reliable tracer peak, because it is not present in other types of dust (mineral, tyre, Saharan etc). As shown by the comparison with ambient data from a number of locations, the aerodynamic lens is not as efficient in detecting brake wear particles, with less than 1% of sampled particles attributed to brake wear. Five field campaigns within Birmingham (background, roadside (3) and road tunnel) used the nozzle inlet and showed that dust particles (crustal and road) accounted for between 3.1 and 65.9% of the particles detected, with the remaining particles being made up from varying percentages of other constituents.

  10. Toroidal rotation braking with n = 1 magnetic perturbation field on JET

    DEFF Research Database (Denmark)

    Sun, Y; Liang, Y; Koslowski, H R;

    2010-01-01

    A strong toroidal rotation braking has been observed in plasmas with application of an n = 1 magnetic perturbation field on the JET tokamak. Calculation results from the momentum transport analysis show that the torque induced by the n = 1 perturbation field has a global profile. The maximal value...

  11. Design and research on the electronic parking brake system of the medium and heavy duty vehicles

    Directory of Open Access Journals (Sweden)

    Hongliang WANG

    2015-04-01

    Full Text Available Focusing on auto control of parking brake system of the medium and heavy duty vehicles, the key problems are studied including the system design and control strategies. The structure and working principle of the parking brake system of the medium and heavy duty vehicles are analyzed. The functions of EPB are proposed. The important information of the vehicle are analyzed which could influence the EPB system. The overall plan of the pneumatic EPB system is designed, which adopts the two-position three-way electromagnetic valve with double coil as actuator. The system could keep the vehicle parking brake status or parking release status for a long time without power supply. The function modules of the system are planned, and the control strategies of automatic parking brake and parking release are made. The experiment is performed on a medium-sized commercial vehicle which is experimentally modified. The overall plan of the pneumatic EPB system and the automatic parking function are proved through real vehicle tests.

  12. DISTRIBUTION OF TRACTION AND BRAKING FORCES ON VEHICLE’S UNDER DIFFERENT RIDING CYCLES

    OpenAIRE

    Ivanov, A; А. Timkov

    2011-01-01

    The method calculation wich can been used to determine the distribution of traction and braking force of the vehicle in different driving cycles and use it when choosing characteristics of a hybrid vehicle deviced. The differential equation of vehicle’s motion basis of Newton’s second law lies in the basis of the given methodology.

  13. Design and preliminary validation of a tool for the simulation of train braking performance

    Institute of Scientific and Technical Information of China (English)

    Luca Pugi; Monica Malvezzi; Susanna Papini; Gregorio Vettori

    2013-01-01

    Train braking performance is important for the safety and reliability of railway systems. The availability of a tool that allows evaluating such performance on the basis of the main train features can be useful for train system designers to choose proper dimensions for and optimize train’s subsystems. This paper presents a modular tool for the prediction of train braking performance, with a par-ticular attention to the accurate prediction of stopping distances. The tool takes into account different loading and operating conditions, in order to verify the safety require-ments prescribed by European technical specifications for interoperability of high-speed trains and the corresponding EN regulations. The numerical results given by the tool were verified and validated by comparison with experi-mental data, considering as benchmark case an Ansaldo EMU V250 train-a European high-speed train-currently developed for Belgium and Netherlands high-speed lines, on which technical information and experimental data directly recorded during the preliminary tests were avail-able. An accurate identification of the influence of the braking pad friction factor on braking performances allowed obtaining reliable results.

  14. Braking, steering, and wear performance of radial-belted and bias-ply aircraft tires

    Science.gov (United States)

    Yager, Thomas J.; Davis, Pamela A.; Stubbs, Sandy M.; Martinson, Veloria J.

    1992-01-01

    Preliminary steering, braking, and tread wear performance results from testing of radial-belted and bias-ply aircraft tires at NASA Langley are described. An overview of the joint NASA/FAA/industry START program is presented. Attention is given to the Langley Test Facility, equipment and future activities.

  15. THE ASSESSMENT OF BASIC TECHNICAL PARAMETERS OF THE COOLING SYSTEM OF THE LOCOMOTIVE DISK BRAKE

    Directory of Open Access Journals (Sweden)

    I. M. Biloborodova

    2009-04-01

    Full Text Available In the article a thermal (constructive calculation of the liquid-air recuperative heat exchanger is executed. Its purpose was an estimation of the areas of heat-exchange surfaces and the consumption of heat carriers necessary for dissipation of thermal energy generated by a locomotive disk brake.

  16. Frictional couplings of wheel with a rail in a brake control system of rail vehicles

    Directory of Open Access Journals (Sweden)

    A. Baier

    2011-06-01

    Full Text Available Purpose: Discussion on use of frictional coupling of wheel with a rail for detection of surface condition of track ways in coal mine undergrounds is the paper objective.Design/methodology/approach: The method for detection of surface condition of track ways is based on using of dedicated converter installed on the locomotive chassis with active part in a form of “tracking wheel” that moves on the rail surface together with the locomotive. The converter is equipped with a system for torque load and a sensor measuring its rotational speed. Change of track surface is determined by momentary changes in rotational speed of “tracking wheel” due to its slippage.Findings: The described method for detection of track ways surface condition enables to generate information signal which transferred to master braking control system of the locomotive eliminates excessive slippage during braking.Research limitations/implications: The presented results confirm rightness of accepted method for detection of track ways surface condition indicating for necessity of modification of developed test rig to get repeatable information about current track surface.Originality/value: The method for detection of track ways surface condition is the novelty approach to braking of rail locomotives used in the mining industry. It is also an alternative option to the present solutions based on known ABS (Anti-Lock Braking System system used in automotive industry.

  17. 49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.

    Science.gov (United States)

    2010-10-01

    ... word, words or abbreviation, in accordance with the requirements of Standard No. 101 (49 CFR 571.101... of brake fluid as specified in 49 CFR 571.116, e.g., “DOT 3”). The lettering shall be— (a... 49 Transportation 6 2010-10-01 2010-10-01 false Standard No. 105; Hydraulic and electric...

  18. MR-fluid yield surface determination in disc-type MR rotary brakes

    International Nuclear Information System (INIS)

    Magneto-rheological (MR) fluids are currently attracting a great deal of attention because of their unique rheological behavior. Many devices have been designed using MR fluids, and of potential interest here are disc-type MR rotary brakes. The plug flow region in MR devices is defined as the region where the fluid is not flowing. The plug flow region plays an important role in design and analysis of MR devices. In MR dampers, the damping coefficient is a function of the plug thickness. In MR valves, the plug thickness is used to control the flow rate through, and the pressure drop across, the MR valve. A MR clutch is performing at the highest efficiency when the entire MR gap is the plug region. For an MR rotary brake, the highest restraining torque is obtained when the entire gap is the plug region as far as there are no wall slip effects. In this paper, using the Bercovier and Engelman constitutive model, the MR fluid flow in disc-type MR brakes is modeled to determine the plug flow region. The resulting system of equations is solved numerically. It is shown that the existence of a plug flow region in the brake will affect the control torque ratio. Better estimation of the plug flow region results in better estimation of the viscous torque

  19. 发动机制动技术运用分析%The car engine braking technology application research

    Institute of Scientific and Technical Information of China (English)

    陈东照

    2014-01-01

    当今汽车逐渐向大功率、高速度等方向发展,对汽车制动性能提出了越来越高的要求。为了减少交通事故,保证行车安全,有效利用发动机辅助制动技术显得尤为重要。本文通过分析发动机制动工作原理及其对汽车制动性能的影响,发动机缓速器和发动机排气辅助制动装置的结构特点、工作特性,提出了实施发动机制动的必要性和发动机制动技术运用要领。%The car of high power, high speed development, put forward higher request for the automobile braking performance. In order to reduce traffic accidents, ensure the safety of driving, the effective use of auxiliary engine brake technology is very important. In this paper, by analyzing the braking principle of engine and its effect on the automobile braking performance, structure characteristics, engine retarder and engine exhaust auxiliary braking device operating characteristics, put forward the necessity of engine brake and engine braking technology essentials.

  20. 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.

  1. 发动机辅助制动性能仿真研究%Performance Simulation of Engine Supplementary Brake

    Institute of Scientific and Technical Information of China (English)

    龚金科; 颜胜; 黄张伟; 贾国海

    2014-01-01

    通过对发动机辅助制动工作过程进行理论分析,建立了发动机辅助制动计算模型,根据辅助制动相关参数(包括排气门开度、发动机转速和排气背压等),对发动机辅助制动进行了单因素和多因素条件下的仿真研究及试验验证。结果表明:随着发动机转速的升高,缸内压力增大,且压力峰值更靠近上止点;制动扭矩随转速的升高而增大,减压制动时制动扭矩最大,发动机制动时制动扭矩最小;发动机转速一定时,泄漏制动和减压制动分别有一对应的最佳排气门开度值,并且转速越高,排气门开度最佳值越大,排气背压越高,制动扭矩越大。%A mathematical model of the engine supplementary brake was set up through discussing the working processes of engine supplementary brake.According to reference parameters of the sup-plementary brake (including the exhaust valve lash,engine speed,exhaust back pressure,etc.),the engine supplementary brake was analyzed with univariate and multivariate conditions by the method of numerical simulations and experimental tests.The results show that the cylinder pressure increases with speed and the peak pressure phase is more near the top dead center(TDC)under the higher speed conditions.The brake torque increases with the engine speed increase.The de-compressure brake has a maximum brake torque while the engine brake has the minimum brake torque.When the engine speed is constant,the bleeding brake and the de-compressure brake have a corresponding optimal ex-haust valve lash,respectively.The higher the speed is,the bigger the exhaust valve lash is.The higher the exhaust back pressure is,the more the brake torque is.

  2. Collapse of massive magnetized dense cores using radiation-magneto-hydrodynamics: early fragmentation inhibition

    CERN Document Server

    Commercon, Benoit; Henning, Thomas

    2011-01-01

    We report the results of radiation-magneto-hydrodynamics calculations in the context of high mass star formation, using for the first time a self-consistent model for photon emission (i.e. via thermal emission and in radiative shocks) and with the high resolution necessary to resolve properly magnetic braking effects and radiative shocks on scales <100 AU. We investigate the combined effects of magnetic field, turbulence, and radiative transfer on the early phases of the collapse and the fragmentation of massive dense cores. We identify a new mechanism that inhibits initial fragmentation of massive dense cores, where magnetic field and radiative transfer interplay. We show that this interplay becomes stronger as the magnetic field strength increases. Magnetic braking is transporting angular momentum outwards and is lowering the rotational support and is thus increasing the infall velocity. This enhances the radiative feedback owing to the accretion shock on the first core. We speculate that highly magnetiz...

  3. Magnetic braking of stellar cores in red giants and supergiants

    CERN Document Server

    Maeder, Andre

    2014-01-01

    Magnetic configurations, stable on the long term, appear to exist in various evolutionary phases, from Main-Sequence stars to white dwarfs and neutron stars. The large scale ordered nature of these fields, often approximately dipolar, and their scaling according to the flux conservation scenario favor the model of a fossil field (Duez et al. 2010). We make some first estimates of the magnetic coupling between the stellar cores and the outer layers in red giants and supergiants. Analytical expressions of the truncation radius of the field coupling are established for a convective envelope and for a rotating radiative zone with horizontal turbulence. The timescales of the internal exchanges of angular momentum are considered. Numerical estimates are made on the basis of recent model grids. The direct magnetic coupling of the core to the extended convective envelope of red giants and supergiants appears unlikely. However, we find that the intermediate radiative zone is fully coupled to the core during the He-bur...

  4. Sustainable urban rail systems: Strategies and technologies for optimal management of regenerative braking energy

    International Nuclear Information System (INIS)

    Highlights: • Review of principal regenerative braking strategies and technologies for urban rail. • Different energy storage technologies are assessed for use in urban rail. • Optimising timetables is a preferential measure to improve energy efficiency. • Energy storage systems improve efficiency and reliability of urban rail systems. • Reversible substations allow for a complete recovery of braking energy. - Abstract: In a society characterised by increasing rates of urbanisation and growing concerns about environmental issues like climate change, urban rail transport plays a key role in contributing to sustainable development. However, in order to retain its inherent advantages in terms of energy consumption per transport capacity and to address the rising costs of energy, important energy efficiency measures have to be implemented. Given that numerous and frequent stops are a significant characteristic of urban rail, recuperation of braking energy offers a great potential to reduce energy consumption in urban rail systems. This paper presents a comprehensive overview of the currently available strategies and technologies for recovery and management of braking energy in urban rail, covering timetable optimisation, on-board and wayside Energy Storage Systems (ESSs) and reversible substations. For each measure, an assessment of their main advantages and disadvantages is provided alongside a list of the most relevant scientific studies and demonstration projects. This study concludes that optimising timetables is a preferential measure to increase the benefits of regenerative braking in any urban rail system. Likewise, it has been observed that ESSs are a viable solution to reuse regenerative energy with voltage stabilisation and energy saving purposes. Electrochemical Double Layer Capacitors has been identified as the most suitable technology for ESSs in general, although high specific power batteries such as Li-ion may become a practical option for on

  5. Friction and wear studies on the temperature dependence of brake-pad materials containing brass

    Directory of Open Access Journals (Sweden)

    Eddoumy Fatima

    2013-11-01

    Full Text Available Brake pad materials for automobile applications are basically polymer matrix composites. Various reinforcing constituents used in brake pads are organic, metallic and ceramic fillers which play among others an important role on the mechanical and thermal properties, and the wear resistance at high temperature. Friction and wear depend on various parameters such as the micro-chemical structure of the pad and of the metallic counter-face, the rotation speed, the pressure, and the contact surface temperature (M.G. Jacko 1983. This latter parameter can be locally as high as 600 up to 1.500 ∘C depending on the brake type (M.G. Jacko 1983; Blau 2001. Thermal models have been developed to study interface effects at contacting surfaces (Majcherczak, Dufrenoy et al. 2007. Frictional energy can be dissipated through different mechanisms such as oxidation, rise in temperature, formation of wear particles, entropy changes associated to viscoelastic and viscoplastic deformation, and noise generation (Eddoumy, Addiego et al. 2011. Studies of friction brake show that more than 95% of the dissipated energy is transformed into heat (Kasem, Thevenet et al.; Majcherczak, Dufrenoy et al. 2007. Thermal analysis is therefore a primordial step in the study of brake systems since it provides thermo-mechanical properties (Majcherczak, Dufrenoy et al. 2007. The influence of the addition of metallic fibers on the performance of organic friction composites has been investigated using friction tests (Qu, Zhang et al. 2004. Benefits or limitations of the different fibers have been reported, however the issues of thermo-mechanical properties or effect of temperature on friction and wear behavior were not yet investigated (Bijwe, Kumar et al. 2008. No effort was done to correlate the thermo-mechanical and thermal properties with the friction and wear behavior. An important prerequisite is to get a good understanding on how brake materials behave. However, a link

  6. DETERMINATION OF STOPPING DISTANCE OF UNPOWERED ROLLING STOCK BY METHOD OF SEQUENTIAL BRAKING

    Directory of Open Access Journals (Sweden)

    O. H. Reidemeister

    2015-09-01

    Full Text Available Purpose. In the paper it is necessary to estimate the determination accuracy of a car stopping distance during the test by the method of sequential braking. The method of sequential braking is applied for experimental evaluation of the stopping distances. Unlike the abandonment method when a sample car is disconnected from the tractive connection and they record the stopping distance of a single car from the moment of uncoupling to the moment of stop, the method of sequential braking involves stopping distance measurement of the tractive connection, the integrity of which in the course of the test is not affected, but its set (locomotive, locomotive with the track test car or with a sample car at the different stages of the test is changed. Direct measuring of the stopping distance of a sample car is not possible using this way, it requires calculating of the stopping distance values of the tractive connection. This adversely affects the accuracy of the result, but it can increase the safety level of the test. Methodology. To evaluate the accuracy researches have conducted the numerical experiment, which simulated experimental processing of stopping distance values. An error was found by giving disturbance of basic data (stopping distance of tractive connection of different configuration and analyzing the resulted scatter of readings (stopping distance of a single car. Findings. The study proved: 1 the relative error of car stopping distances value, with relative error of basic data 1%, made 3.3-19.7% (depending on the tractive connection variant. 2 the proposed ways of error reduction (without track test car, less-weighed-locomotive use allowed declining the error to 2.15-5.1%. Originality. The methodology of error estimation of car stopping distances determination under tests by the method of sequential braking was proposed. Practical value. Work results make it possible to replace the running brake tests by the abandonment method, under which

  7. Contribution of MoS{sub 2} additives to the microstructure and properties of PM copper based brake material

    Energy Technology Data Exchange (ETDEWEB)

    Uzunsoy, Deniz; Kelesoglu, Erguen; Erarslan, Yaman [Yildiz Technical Univ. (Turkey). Metallurgical and Materials Engineering Dept.

    2009-07-01

    The effect of a MoS{sub 2} additive on the microstructural evolution and properties of copper based brake linings has been investigated in this study. It was found that the quantity of additive as well as sintering cycle has significant effect on the density and hardness values of the produced material. The microstructure of designed brake lining materials showed that copper based matrix was surrounded by MoS{sub 2} particles. The microstructural investigation also proved that the lower boiling point elements such as Pb in the as-supplied powder vaporise during sintering from the structure, and this result in an increase in the porosity amount by lowering the overall density of brake linings. The Vickers hardness of brake linings decreased with the addition of molybdenum disulphide particles. MoS{sub 2} addition reduces wear rate of samples due to the solid lubrication effect. (orig.)

  8. Dynamic analysis and control of an anti-lock brake system for a motorcycle with a camber angle

    Science.gov (United States)

    Huang, C. K.; Shih, M. C.

    2011-04-01

    This paper analyses the dynamic response of a motorcycle with an anti-lock brake system (ABS) and camber or steering angle. Most studies have assumed that motorcycles brake in a straight line - that is, without a steering or camber angle. In this work, the performance of an ABS modulator is designed and analysed at first. Then, a controller is designed for motorcycle turning. The controller uses angular acceleration and the pressure value in brake calipers on the front and rear wheels, camber angle and lateral acceleration as commands to control brake pressure on each wheel to prevent wheel locking. The equation of motion for a motorcycle is based on Weir's equations. This motorcycle model combines a mathematical equation of the ABS modulator, tyre model and controller in simulations.

  9. Analysis of torque transmitting behavior and wheel slip prevention control during regenerative braking for high speed EMU trains

    Science.gov (United States)

    Xu, Kun; Xu, Guo-Qing; Zheng, Chun-Hua

    2016-03-01

    The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability, improving the adhesion utilization, and achieving deep energy recovery. There remain technical challenges mainly because of the nonlinear, uncertain, and varying features of wheel-rail contact conditions. This research analyzes the torque transmitting behavior during regenerative braking, and proposes a novel methodology to detect the wheel-rail adhesion stability. Then, applications to the wheel slip prevention during braking are investigated, and the optimal slip ratio control scheme is proposed, which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control. The proposed methodology achieves the optimal braking performance without the wheel-rail contact information. Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.

  10. Analysis of torque transmitting behavior and wheel slip prevention control during regenerative braking for high speed EMU trains

    Science.gov (United States)

    Xu, Kun; Xu, Guo-Qing; Zheng, Chun-Hua

    2016-04-01

    The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability, improving the adhesion utilization, and achieving deep energy recovery. There remain technical challenges mainly because of the nonlinear, uncertain, and varying features of wheel-rail contact conditions. This research analyzes the torque transmitting behavior during regenerative braking, and proposes a novel methodology to detect the wheel-rail adhesion stability. Then, applications to the wheel slip prevention during braking are investigated, and the optimal slip ratio control scheme is proposed, which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control. The proposed methodology achieves the optimal braking performance without the wheel-rail contact information. Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.

  11. 计算机数据采集系统在提升机闸瓦制动工况分析中的应用%Application of Computer Data Acquisition System in Hoist Brake Shoe Braking Condition Analysis

    Institute of Scientific and Technical Information of China (English)

    潘武敏

    2013-01-01

    随着计算机数据处理技术的发展,数据采集系统应用到各大生产企业中。文章以矿井提升机制动问题为研究基础,提出了提升机闸瓦制动工况采集系统,通过对该系统的温度、压力以及速度传感器的选择及通信问题设计,实现了提升机闸瓦制动工况的实时数据采集,为今后的提升机制动问题分析提供了可靠的理论依据。%Along with the computer data processing technology development, data acquisition system is applied to the major work of enterprise.This article of mine hoist braking problems as the research foundation, developed to hoist brake shoe braking system.The system of temperature, pressure and speed sensor selection and communication design, realization of hoist brake shoe braking mode of the real-time data collection, for the future of the hoist braking problem analysis provides a reliable theoretical basis.

  12. Pathogenesis of tropical sprue: A pilot study of antroduodenal manometry, duodenocaecal transit time & fat-induced ileal brake

    OpenAIRE

    Uday C Ghoshal; Sunil KUMAR; Misra, Asha; Choudhuri, Gourdas

    2013-01-01

    Background & objectives: Small intestinal bacterial overgrowth (SIBO) due to ileal brake-induced hypomotility may cause tropical sprue (TS). We evaluated effect of infusion of fat or placebo in duodenum randomly in patients with TS and healthy controls on antroduodenal manometry (ADM) and mediators of ileal brake, and duodenocaecal transit time (DCTT). Methods: ADM and DCTT (lactulose hydrogen breath test, HBT) were evaluated with placebo and fat in eight controls and 13 patients with TS (dia...

  13. Pathogenesis of tropical sprue: A pilot study of antroduodenal manometry, duodenocaecal transit time & fat-induced ileal brake

    OpenAIRE

    Uday C Ghoshal; Sunil Kumar; Asha Misra; Gourdas Choudhuri

    2013-01-01

    Background & objectives: Small intestinal bacterial overgrowth (SIBO) due to ileal brake-induced hypomotility may cause tropical sprue (TS). We evaluated effect of infusion of fat or placebo in duodenum randomly in patients with TS and healthy controls on antroduodenal manometry (ADM) and mediators of ileal brake, and duodenocaecal transit time (DCTT). Methods: ADM and DCTT (lactulose hydrogen breath test, HBT) were evaluated with placebo and fat in eight controls and 13 patients with TS ...

  14. Engineering report. Part 2: NASA wheel and brake material tradeoff study for space shuttle type environmental requirements

    Science.gov (United States)

    Bok, L. D.

    1973-01-01

    The study included material selection and trade-off for the structural components of the wheel and brake optimizing weight vs cost and feasibility for the space shuttle type application. Analytical methods were used to determine section thickness for various materials, and a table was constructed showing weight vs. cost trade-off. The wheel and brake were further optimized by considering design philosophies that deviate from standard aircraft specifications, and designs that best utilize the materials being considered.

  15. An Exploration of the Offset Hypothesis Using Disaggregate Data:The Case of Airbags and Antilock Brakes

    OpenAIRE

    Maheshri, Vikram; Mannering, Fred; Winston, Clifford

    2006-01-01

    The offset hypothesis predicts consumers adapt to innovations that improve safety by becoming less vigilant about safety. Previous tests have used aggregate data that may confound the effect of a safety policy with those consumers who are most affected by it. We test the hypothesis using disaggregate data to analyze the effects of airbags and antilock brakes on automobile safety. We find that safety-conscious drivers are more likely than other drivers to acquire airbags and antilock brakes bu...

  16. Traction system for electric vehicles using a variable frequency three-phase induction motor driver with regenerative braking

    OpenAIRE

    Neves, Pedro; Afonso, João L.

    2006-01-01

    This paper describes the development and implementation of a traction system, based in the utilization of a three-phase induction motor controlled by a Power Electronics Inverter, to be used in electric vehicles. This system allows the speed control of the vehicle, forwards and backwards, and also permits regenerative braking. The induction motor is fed, through the inverter, by a set of batteries. During the operation in the regenerative braking mode, the induction motor returns, through the...

  17. Parameter Analysis on Torque Stabilization for the Eddy Current Brake: A Developed Model, Simulation, and Sensitive Analysis

    Directory of Open Access Journals (Sweden)

    Quan Zhou

    2015-01-01

    Full Text Available Eddy current brake (ECB is an attractive contactless brake whereas it suffers from braking torque attenuation when the rotating speed increases. To stabilize the ECB’s torque generation property, this paper introduces the concept of anti-magneto-motive force to develop the ECB model on the fundamental of magnetic circles. In the developed model, the eddy current demagnetization and the influence of temperature which make the braking torque attenuation are clearly presented. Using the developed model of ECB, the external and internal characteristics of the ECB are simulated through programming by MATLAB. To find the sensibility of the influences on ECB’s torque generation stability, the stability indexes are defined and followed by a sensibility analysis on the internal parameters of an ECB. Finally, this paper indicates that (i the stability of ECB’s torque generating property could be enhanced by obtaining the optimal combination of “demagnetization speed point and the nominal maximum braking torque.” (ii The most remarkable influencing factor on the shifting the demagnetization speed point of ECB was the thickness of the air-gap. (iii The radius of pole shoe’s cross section area and the distance from the pole shoe center to the rotation center are both the most significant influences on the nominal maximum braking torque.

  18. Using ABS Vehicle Braking Performance Analysis%装用ABS车辆的制动性能分析

    Institute of Scientific and Technical Information of China (English)

    王德江

    2012-01-01

    汽车制动系统在汽车的安全方面起着至关重要的作用,ABS在保持汽车制动时的方向稳定性并有限度地缩短制动距离、提高汽车制动安全性方面作用明显,使得全世界对ABS的应用都非常重视。在介绍ABS基本原理的基础上,对车辆制动进行受力分析,通过对有无ABS时的性能进行分析对比,说明有ABS工作时汽车制动力的变化频率大,对工程实践具有指导意义。%The automobile brake system in vehicle safety plays a crucial role in keeping the car,ABS braking directional stability and limit to shorten the braking distance,improve the automobile braking safety aspects of the role,making the whole world for ABS applications are very seriously.On the introduction of ABS on the basis of the basic principle,the vehicle braking force analysis,by contrast with or without ABS performance analysis,illustrates the ABS work of the automobile braking force changes in frequency,the project has guiding significance.

  19. Radiative, magnetic and numerical feedbacks on small-scale fragmentation

    CERN Document Server

    Commercon, Benoit; Audit, Edouard; Chabrier, Gilles; Teyssier, Romain

    2010-01-01

    Radiative feedback and magnetic field are understood to have a strong impact on the protostellar collapse. We present high resolution numerical calculations of the collapse of a 1 solar mass dense core in solid body rotation, including both radiative transfer and magnetic field. Using typical parameters for low-mass cores, we study thoroughly the effect of radiative transfer and magnetic field on the first core formation and fragmentation. We show that including the two aforementioned physical processes does not correspond to the simple picture of adding them separately. The interplay between the two is extremely strong, via the magnetic braking and the radiation from the accretion shock.

  20. Feasibility of controlling speed-dependent low-frequency brake vibration amplification by modulating actuation pressure

    Science.gov (United States)

    Sen, Osman Taha; Dreyer, Jason T.; Singh, Rajendra

    2014-12-01

    In this article, a feasibility study of controlling the low frequency torque response of a disc brake system with modulated actuation pressure (in the open loop mode) is conducted. First, a quasi-linear model of the torsional system is introduced, and analytical solutions are proposed to incorporate the modulation effect. Tractable expressions for three different modulation schemes are obtained, and conditions that would lead to a reduction in the oscillatory amplitudes are identified. Second, these conditions are evaluated with a numerical model of the torsional system with clearance nonlinearity, and analytical solutions are verified in terms of the trends observed. Finally, a laboratory experiment with a solenoid valve is built to modulate actuation pressure with a constant duty cycle, and time-frequency domain data are acquired. Measurements are utilized to assess analytical observations, and all methods show that the speed-dependent brake torque amplitudes can be altered with an appropriate modulation of actuation pressure.

  1. IN-SITU MEASUREMENTS OF VIBRATIONS OF ELASTICALLY SUPPORTED STEEL REINFORCED CONCRETE BRIDGE DURING CAR BRAKING

    Directory of Open Access Journals (Sweden)

    S. Yu. Gridnev

    2011-02-01

    Full Text Available Problem statement. Dynamic effect of increasing transport flows is produced not only on bearing structures of bridges but also on supports, which leads to their uniform non-steady state deformation.Results and conclusions. An optical displacement controller is proposed to be used for remote record of vibrations of elastically supported steel reinforced concrete bridge and supporting part's deformation. Device structure, scheme of its calibration and of determination of maximum accuracy are described, as well as technique and results of dynamic tests of vibrations of elastically supported span of steel reinforced concrete bridge during single car braking with different accelerations in the beginning of braking in different cross-sections. The analysis of the results is performed.

  2. Nonlinear time series analysis of vibration data from a friction brake: SSA, PCA, and MFDFA

    International Nuclear Information System (INIS)

    We use the methodology of singular spectrum analysis (SSA), principal component analysis (PCA), and multi-fractal detrended fluctuation analysis (MFDFA), for investigating characteristics of vibration time series data from a friction brake. SSA and PCA are used to study the long time-scale characteristics of the time series. MFDFA is applied for investigating all time scales up to the smallest recorded one. It turns out that the majority of the long time-scale dynamics, that is presumably dominated by the structural dynamics of the brake system, is dominated by very few active dimensions only and can well be understood in terms of low dimensional chaotic attractors. The multi-fractal analysis shows that the fast dynamical processes originating in the friction interface are in turn truly multi-scale in nature

  3. Robust Switched Predictive Braking Control for Rollover Prevention in Wheeled Vehicles

    Directory of Open Access Journals (Sweden)

    Martín Antonio Rodríguez Licea

    2014-01-01

    Full Text Available The aim of this paper is to propose a differential braking rollover mitigation strategy for wheeled vehicles. The strategy makes use of a polytopic (piecewise linear description of the vehicle and includes translational and rotational dynamics, as well as suspension effects. The braking controller is robust and the system states are predicted to estimate the rollover risk up to a given time horizon. In contrast to existing works, the switched predictive nature of the control allows it to be applied only when risk of rollover is foreseen, interfering a minimum with driver’s actions. The stability of the strategy is analyzed and its robustness is illustrated via numerical simulations using CarSim for a variety of vehicles.

  4. 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

  5. A modified approach to transient stability enhancement with fast valving and braking resistor applications

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Ramnarayan [Indian Institute of Technology, Roorkee, Uttaranchal (India). Department of Electrical Engineering; Bhatti, T.S.; Kothari, D.P. [Indian Institute of Technology, Delhi, New Delhi (India). Centre for Energy Studies

    2006-12-15

    Fast valving and braking resistor are two important members of the family of the discrete supplementary controllers (DISCOS). Both of these are very effective and economic means of transient stability enhancement under extreme contingencies. Being stationed at the similar end of a power system the two schemes carry a very good potential of an effective coordination. Such a coordinated control is helpful not only in obtaining an improved gain in stability, but also in overcoming the limitations and avoiding excessive duty on the part of an individual controller. In this work, a detailed study has been carried out to evaluate the scope and limitations of fast valving and dynamic braking resistor controls in enhancing the transient stability of power systems. Improvements have been suggested over the conventional schemes of control so as to improve their adaptability under different conditions of fault and loading or with different types of generating units. (author)

  6. Development of Quasi-3DOF upper limb rehabilitation system using ER brake: PLEMO-P1

    International Nuclear Information System (INIS)

    In recent years, many researchers have studied the potential of using robotics technology to assist and quantify the motor functions for neuron-rehabilitation. Some kinds of haptic devices have been developed and evaluated its efficiency with clinical tests, for example, upper limb training for patients with spasticity after stroke. However, almost all the devices are active-type (motor-driven) haptic devices and they basically require high-cost safety system compared to passive-type (brake-based) devices. In this study, we developed a new practical haptic device 'PLEMO-P1'; this system adopted ER brakes as its force generators. In this paper, the mechanism of PLEMO-P1 and its software for a reaching rehabilitation are described.

  7. C/C composite brake disk nondestructive evaluation by IR thermography

    Science.gov (United States)

    Chu, Tsuchin P.; Poudel, Anish; Filip, Peter

    2012-06-01

    This paper discusses the non-destructive evaluation of thick Carbon/Carbon (C/C) composite aircraft brake disks by using transient infrared thermography (IRT) approach. Thermal diffusivity measurement technique was applied to identify the subsurface anomalies in thick C/C brake disks. In addition, finite element analysis (FEA) modeling tool was used to determine the transient thermal response of the C/C disks that were subjected to flash heating. For this, series of finite element models were built and thermal responses with various thermal diffusivities subjected to different heating conditions were investigated. Experiments were conducted to verify the models by using custom built in-house IRT system and commercial turnkey system. The analysis and experimental results showed good correlation between thermal diffusivity value and anomalies within the disk. It was demonstrated that the step-heating transient thermal approach could be effectively applied to obtain the whole field thermal diffusivity value of C/C composites.

  8. Signal Processing for MoC brake rattle noise of moving vehicles using prony analysis

    International Nuclear Information System (INIS)

    To verify the possibility of generating rattling noise from a motor on caliper brake system, a test was conducted using a caliper excited with vibrations similar to that in a vehicle running on actual roads; this test was conducted using a quiet shaker installed in an anechoic room. After several hours of external excitation, the test assembly was loosened, and the frequency of rattling noise generation increased. A microphone was used to record the generated noise. The measured signals were analyzed by conventional spectrum analysis. Since the noise is generated as an impact response, the advantages of employing Prony analysis was discussed, and the results were compared to those obtained using conventional fast Fourier transforms. The accuracy of Prony analysis was through endurance tests on different brake systems

  9. Signal Processing for MoC brake rattle noise of moving vehicles using prony analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Cheol; Kwak, Yun Sang; Park, Jun Hong [Dept. of Mechanical Convergence Engineering, Hanyang University, Seoul (Korea, Republic of)

    2015-08-15

    To verify the possibility of generating rattling noise from a motor on caliper brake system, a test was conducted using a caliper excited with vibrations similar to that in a vehicle running on actual roads; this test was conducted using a quiet shaker installed in an anechoic room. After several hours of external excitation, the test assembly was loosened, and the frequency of rattling noise generation increased. A microphone was used to record the generated noise. The measured signals were analyzed by conventional spectrum analysis. Since the noise is generated as an impact response, the advantages of employing Prony analysis was discussed, and the results were compared to those obtained using conventional fast Fourier transforms. The accuracy of Prony analysis was through endurance tests on different brake systems.

  10. Magnetic braking of stellar cores in red giants and supergiants

    Energy Technology Data Exchange (ETDEWEB)

    Maeder, André; Meynet, Georges, E-mail: andre.maeder@unige, E-mail: georges.meynet@unige.ch [Geneva Observatory, Geneva University, CH-1290 Sauverny (Switzerland)

    2014-10-01

    Magnetic configurations, stable on the long term, appear to exist in various evolutionary phases, from main-sequence stars to white dwarfs and neutron stars. The large-scale ordered nature of these fields, often approximately dipolar, and their scaling according to the flux conservation scenario favor a fossil field model. We make some first estimates of the magnetic coupling between the stellar cores and the outer layers in red giants and supergiants. Analytical expressions of the truncation radius of the field coupling are established for a convective envelope and for a rotating radiative zone with horizontal turbulence. The timescales of the internal exchanges of angular momentum are considered. Numerical estimates are made on the basis of recent model grids. The direct magnetic coupling of the core to the extended convective envelope of red giants and supergiants appears unlikely. However, we find that the intermediate radiative zone is fully coupled to the core during the He-burning and later phases. This coupling is able to produce a strong spin down of the core of red giants and supergiants, also leading to relatively slowly rotating stellar remnants such as white dwarfs and pulsars. Some angular momentum is also transferred to the outer convective envelope of red giants and supergiants during the He-burning phase and later.

  11. [An automatic torque control system for a bicycle ergometer equipped with an eddy current brake].

    Science.gov (United States)

    Kikinev, V V

    2007-01-01

    The main elements of the loading device of a bicycle ergometer, including an eddy current brake and a torque sensor, are described. The automatic torque control system, which includes the loading device, is equipped with a stabilizing feedback controller that optimally approximates the closed-loop transfer function of the target model. The reduced transfer function model of the controller is of the fourth order. A method featuring a modulation-demodulation loop is suggested for implementation of the control system. PMID:17598478

  12. Nonequilibrium tribology friction interaction of friction pairs of braking devices (part two)

    OpenAIRE

    ЖУРАВЛЕВ, Д. Ю.; Івано - Франківський національний технічний університет нафти і газу

    2016-01-01

    A robust approach to the analysis and design of band-shoe brake friction units of lifting andtransportation equipment is based on forecasting processes, phenomena and effects accompanyingtheir friction pairs. It includes the state of their surface and subsurface layers relating tothe quality of friction surfaces, durability and stabilization of operating parameters. In addition,it is observed regulation and control of operating parameters at electro-thermo-mechanicalfriction. The paper examin...

  13. On Airborne Wear Particles Emissions ofCommercial Disc Brake Materials– A Pin on Disc Simulation

    OpenAIRE

    Söderberg, Anders; Wahlström, Jens; Olander, Lars; Jansson, Anders; Olofsson, Ulf

    2008-01-01

    A novel test method was used to study the concentration and size distribution of airborne wear particles from disc brake materials. A pin-on-disc tribometer equipped with particle counting instruments was used as test equipment. Four different nonasbestoses-organic (NAO) linings for the U.S. market and four different low metallic linings for the EU market were tested against material from gray cast iron rotors. The result indicates that the low metallic linings are more aggressive to the roto...

  14. Inverter-fed induction motor simulation under overloading for regenerative braking management in electric vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Papazacharopoulos, Z; Tatis, K.; Kladas, A.; Manias, S.; Tegopoulos, J. [National Technical University of Athens, Electric Power Division, Laboratory of Electrical Machines, Athens (Greece)

    2000-08-01

    The paper introduces a dynamic model for inverter-fed induction motor drive system, enabling accurate simulation under limited motor overloading during regenerative braking. This model includes a conveniently modified equivalent circuit for the motor analysis and has been checked by measurements on a 20 kW experimental set-up. The considered motor overloading may provide substantial energy savings in the domain of electromotion, in traction systems such as electric vehicles and relevant industrial applications. (orig.)

  15. Automotive Brake Materials: Characterization of Wear Products and Relevant Mechanisms at High Temperature

    OpenAIRE

    Verma, Piyush Chandra

    2016-01-01

    Wear is an ubiquitous phenomenon affecting an extremely wide number of technological system, often determining their premature failure. In this regard, wear and friction behavior of friction materials and the characterization of wear debris from brake disc system is an important step to understand the dominant wear mechanisms active in a given tribological system, in order to improve its performances and to increase the expected lifetime. In the thesis, four tribological task has been perform...

  16. An Investigation of Maximum Brake Torque Timing based on Ionization Current Feedback

    OpenAIRE

    Magnusson, Janek

    2007-01-01

    For every operating condition of an internal combustion engine there exists an optimal spark timing, called maximum brake torque (MBT), which maximises the output torque and the efficiency of the engine. Traditionally MBT timing is implemented as an open-loop control where the ignition timing is found by using a combination of static lookup tables and sensor information. With a direct closed-loop control from the combustion process the performance of internal combustion engines could be impro...

  17. Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers.

    OpenAIRE

    Dumortier, P; De Vuyst, P; Strauss, P.; Yernault, J C

    1990-01-01

    Asbestos body (AB) concentrations in bronchoalveolar lavage samples of 15 brake lining (BL) workers exposed only to chrysotile have been determined and compared with those from 44 asbestos cement (AC) workers extensively exposed to amphiboles. The mean AB concentrations (263 +/- 802 and 842 +/- 2086 AB/ml respectively) for those groups did not differ significantly but were much higher than those found in control groups. Analytical electron microscopy of asbestos body cores showed that in the ...

  18. Investigation of the relationship between damping and mode-coupling patterns in case of brake squeal

    OpenAIRE

    Fritz, Guillaume; Sinou, Jean-Jacques; Duffal, Jean-Marc; Jezequel, Louis

    2007-01-01

    International audience Brake squeal is a friction induced instability phenomenon that has to be addressed during the development process. The mechanism is considered a mode coupling phenomenon also referred to as coalescence. The system eigenvalues have been computed using a technique based on the finite element method. The coalescence patterns were then determined in relation to the friction coefficient. The effects of damping on the coalescence patterns have been investigated. If the two...

  19. Development of eco-friendly brake friction composites containing flax fibers

    OpenAIRE

    Fu, Zhezhen; Suo, Baoting; Yun, Rongping; Lu, Yimei; Wang, Hui; Qi, Shicheng; Jiang, Shengling; Lu, Yafei; MATĚJKA, Vlastimil

    2012-01-01

    Eco-friendly brake friction composites with good friction performance were developed. The raw materials utilized were selected according to eco-friendly criterion that natural products should be preferably chosen. The formulations are composed of plant flax fiber, mineral basalt fiber, and wollastonite as reinforcements, natural graphite as solid lubricant, zircon as abrasive, vermiculite and baryte as functional and space fillers, and cardanol-based benzoxazine-toughened phenolic resin as bi...

  20. Solubility and accumulation of metals in Chinese brake fern, vetiver and rostrate sesbania using chelating agents.

    Science.gov (United States)

    Lou, L Q; Ye, Z H; Wong, M H

    2007-01-01

    Greenhouse experiments were conducted to study the effects of chelating agents on the growth and metal accumulation of Chinese brake fern (Pteris vittata L.), vetiver (Vetiveria zizanioides L.), and rostrate sesbania (Sesbania rostrata L.) in soil contaminated with arsenic (As), Cu, Pb, and Zn. Among the five chelating agents used [ethylenediaminetriacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), oxalic acid (OA), and phytic acid (PA)], OA was the best to mobilize As, EDTA to mobilize Cu and Pb, and HEDTA to mobilize Zn from soil, respectively. The biomass of vetiver was the highest, followed by rostrate sesbania. All chelating agents inhibited the growth of Chinese brake fern and rostrate sesbania, but HEDTA significantly increased the aboveground biomass of vetiver. Dry weights of both Chinese brake fern and rostrate sesbania decreased with increasing EDTA concentrations amended in the soil, especially in treatments with high EDTA concentrations. EDTA and HEDTA enhanced Cu, Zn, and Pb, but lowered As accumulation in all three plant species, except for As in vetiver, while OA significantly enhanced As accumulation in the aboveground part of vetiver. Concentrations of Cu, Zn, and Pb in the aboveground parts of plants increased significantly with the increase of EDTA concentrations and treatment time. In addition to As, Chinese brake fern also accumulated the highest Cu, Pb, and Zn in its aboveground parts among the three plant species grown in metal-contaminated soil with EDTA/HEDTA treatments. This species, therefore, can be used to simultaneously clean up As, Cu, Pb, and Zn from contaminated soils with the aid of EDTA or HEDTA. PMID:18246709

  1. Desperately Driven and No Brakes: Developmental Stress Exposure and Subsequent Risk for Substance Abuse

    OpenAIRE

    Andersen, Susan L.; Teicher, Martin H.

    2008-01-01

    ANDERSEN, S.L. and TEICHER, M.H. Desperately driven and no brakes: Developmental stress exposure and subsequent risk for substance abuse. NEUROSCI BIOBEHAV REV XX(X) XXX-XXX, 2008. Adverse life events are associated with a wide range of psychopathology, including an increased risk for substance abuse. In this review, we focus on the inter-relationship between exposure to adversity and brain development, and relate this to enhanced windows of vulnerability. This review encompasses clinical and...

  2. Determination Of Correlation Between Road Pavement Skid Resistance And Braking Deceleration

    OpenAIRE

    KOKOT, D; Rijavec, R.; Ambroz, M.

    2012-01-01

    There are many situations when road pavement surface skid resistance drops to unacceptable levels. Skid resistance is an essential pavement property for road safety, but drivers are not able to assess its degree by visual means, although in the end they must be able to stop their vehicles safely within the stopping sight distance. In our research normalized braking deceleration was related to SCRIMTEX SFC values and analyzed for different driving conditions (wet/dry), vehicle systems, skid re...

  3. Study of Influence of Operating Parameters on Braking Friction and Rolling Resistance

    OpenAIRE

    KASBERGEN, Cohr; SCARPAS, Tom; Cerezo, Véronique; SRIRANGAM, Santosh; Anupam, Kumar

    2015-01-01

    Tire-road interaction addresses safety in the context of braking friction and energy efficiency in the context of rolling resistance. These two phenomena are interrelated and their engineering solutions can sometimes be contradictory to each other. For example, high skid resistant surfaces may not be ideal for fuel economy while low rolling resistant surfaces may be prone to skidding. Several past experimental and numerical studies have investigated the individual phenomenon, nevertheless not...

  4. Hardware-in-the-loop of Simulation for a Hydraulic Antilock Brake System

    OpenAIRE

    Ayman A. Aly

    2013-01-01

    Hardware-In-the-Loop (HIL) of simulation policy is used as a rapid and economical tool for developing automotive systems effectively and for dangerous situations tests such as extreme road conditions or high travelling speeds. A method for building a HIL of simulation a hydraulic Antilock Braking System (ABS) based on MATLAB/Simulink is presented in this paper. The system is implemented for research purposes as well as for the application in educational process. It can help the user heighteni...

  5. Stability and Transient Analysis in the Modelling of Railway Disc Brake Squeal

    OpenAIRE

    LORANG, X; CHIELLO, O

    2008-01-01

    The paper deals with friction induced vibrations and especially with railway disc brake squeal. The first part of the paper is devoted to the strategy used to model the general problem of self-excited vibrations of a rotating disc in frictional contact with two pads. Unilateral contact conditions with Coulomb friction and constant friction coefficient are considered. In order to predict the occurrence of self-excited vibrations, a classical stability analysis is performed, which consists on ...

  6. Design And Implementation of Dsp-Based Intelligent Controller For Automobile Braking System

    OpenAIRE

    S.N. Sidek and M.J.E. Salami

    2012-01-01

    An intelligent braking system has great potential applications especially, in developed countries where research on smart vehicle and intelligent highways are receiving ample attention. The system when integrated with other subsystems like automatic traction control, intelligent throttle, and auto cruise systems, etc will result in smart vehicle maneuver. The driver at the end of the day will become the passenger, safety accorded the highest priority and the journey optimized in term of time ...

  7. DOES MAGNETIC-FIELD-ROTATION MISALIGNMENT SOLVE THE MAGNETIC BRAKING CATASTROPHE IN PROTOSTELLAR DISK FORMATION?

    International Nuclear Information System (INIS)

    Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. In the simplest case of a laminar (non-turbulent) core with the magnetic field aligned with the rotation axis, both analytic considerations and numerical simulations have shown that the formation of a large, 102 AU scale, rotationally supported protostellar disk is suppressed by magnetic braking in the ideal MHD limit for a realistic level of core magnetization. This theoretical difficulty in forming protostellar disks is termed the ''magnetic braking catastrophe''. A possible resolution to this problem, proposed by Hennebelle and Ciardi and Joos et al., is that misalignment between the magnetic field and rotation axis may weaken the magnetic braking enough to enable disk formation. We evaluate this possibility quantitatively through numerical simulations. We confirm the basic result of Joos et al. that the misalignment is indeed conducive to disk formation. In relatively weakly magnetized cores with dimensionless mass-to-flux ratio ∼> 4, it enabled the formation of rotationally supported disks that would otherwise be suppressed if the magnetic field and rotation axis are aligned. For more strongly magnetized cores, disk formation remains suppressed, however, even for the maximum tilt angle of 90°. If dense cores are as strongly magnetized as indicated by OH Zeeman observations (with a mean dimensionless mass-to-flux ratio ∼2), it would be difficult for the misalignment alone to enable disk formation in the majority of them. We conclude that, while beneficial to disk formation, especially for the relatively weak field case, misalignment does not completely solve the problem of catastrophic magnetic braking in general

  8. Non-exhaust traffic related emissions – Brake and tyre wear PM

    OpenAIRE

    GRIGORATOS THEODOROS; Martini, Giorgio

    2014-01-01

    Traffic related sources are a significant contributor of particulate matter, particularly in urban environments and major cities. Traffic related particles can be distinguished into: exhaust traffic related particles, which are emitted as a result of incomplete fuel combustion and lubricant volatilization during the combustion procedure, and non-exhaust traffic related particles, which are either generated from non-exhaust traffic related sources such as brake, tyre, clutch and road surface w...

  9. Respiratory impairment due to asbestos exposure in brake-lining workers

    International Nuclear Information System (INIS)

    There is extensive evidence that exposure to asbestos causes pulmonary parenchyma fibrosis, pleural disease, and malignant neoplasm in asbestos-exposed workers. However, few data concerning brake-lining workers are available in the literature. In this study, we aimed to assess the long-term effects of chrysotile asbestos exposure on lung function and the risk of asbestos-related diseases in brake-lining workers. Seventy-four asbestos-exposed workers who processed brake-lining products and 12 unexposed office workers were offered pulmonary function tests (spirometry and transfer actor) in 1992 and 1999. In 1999, the mean duration of asbestos exposure was 0.00±4.07 and 11.02±4.81 years (7-31 years) in non smoking and smoking asbestos workers, respectively. Transfer factor (TL, CO) and transfer coefficient (KCO) decline were significant in the 7-year follow-up in both smoking and non smoking asbestos workers. However, lung function indices of he control group, whom were all current smokers; were also found to be decreased, including FEF75, TL, CO and KCO. We found minimal reticular changes in 10 asbestos workers who were all current smokers, they underwent high-resolution computed tomography scans of the chest and we found that they ad peri bronchial thickening resulting from smoking. As a conclusion, even in the absence of radiographic asbestosis, TL, CO and KCO may decrease after mean 10-year duration of exposure to asbestos in brake-lining workers and this is more noticeable with cigarette burden

  10. Energy Efficiency in Heavy Vehicle Tires, Drivetrains, and Braking Systems; FINAL

    International Nuclear Information System (INIS)

    This document was prepared to support the primary goals of the Department of Energy, Office of Heavy Vehicle Technologies. These were recently stated as follows: ''Develop by 2004 the enabling technologies for a class 7-8 truck with a fuel efficiency of 10 mpg (at 65 mph) which will meet prevailing emission standards. For Class 3-6 trucks operating on an urban driving cycle, develop by 2004 commercially viable vehicles that achieve at least double the fuel economy of comparable current vehicles (1999), and as a research goal, reduce criteria pollutants to 30% below EPA standards. Develop by 2004 the diesel engine enabling technologies to support large-scale industry dieselization of Class 1 and 2 trucks, achieving a 35% fuel efficiency improvement over comparable gasoline-fueled trucks, while meeting applicable emissions standards.'' The enabling technologies for improving the fuel efficiency of trucks, include not only engine technologies but also technologies involved with lowering the rolling resistance of tires, reducing vehicle aerodynamic drag, improving thermal management, and reducing parasitic frictional losses in drive train components. Opportunities also exist for making better use of the energy that might ordinarily be dissipated during vehicle braking. Braking systems must be included in this evaluation since safety in truck operations is vital, and braking requirements are greater for vehicles having lowered resistance to rolling. The Office of Heavy Vehicle Technologies has initiated a program to improve the aerodynamics of heavy vehicles through wind tunnel testing, computational modeling, and on-road evaluations. That activity is described in a separate multi-year plan; therefore, emphasis in this document will be on tires, drive trains, and braking systems. Recent, dramatic fluctuations in diesel fuel prices have emphasized the importance of effecting savings in truck fuel economy by implementing new component designs and materials

  11. PROBABILISTIC APPROACH FOR THE DETERMINATION OF CUTS PERMISSIBLE BRAKING MODES ON THE GRAVITY HUMPS

    Directory of Open Access Journals (Sweden)

    Volodymyr BOBROVSKYI

    2016-03-01

    Full Text Available The paper presents the research results of cuts braking modes on the gravity humps. The objective of this paper is developing the methods for assessment of braking modes of cuts under conditions of fuzziness of their rolling properties, as well as selecting the permissible starting speed range of cuts from retardant positions. As a criterion for assessing the modes of target control of cut rolling speed, it was proposed to use an average gap size on a classification track at the established norms of probable exceeding of permissible speed of cars collision and their stop in retarders. As a criterion for evaluating the modes of interval control of cuts rolling speed, using the risk of their non-separation on the switches was proposed. Using the simulation modeling and mathematical statistics, the configuration of the range of permissible speed of cuts coming out from retardant positions has been set. The conducted researches allow simplifying the choice of cut braking modes in systems of automatic control of cut rolling speed.

  12. Airborne brake wear debris: size distributions, composition, and a comparison of dynamometer and vehicle tests.

    Science.gov (United States)

    Sanders, Paul G; Xu, Ning; Dalka, Tom M; Maricq, M Matti

    2003-09-15

    Particle size distributions of light-duty vehicle brake wear debris are reported with careful attention paid to avoid sampling biases. Electrical low-pressure impactor and micro-orifice uniform deposit impactor measurements yield consistent size distributions, and the net particulate matter mass from each method is in good agreement with gravimetric filter measurements. The mass mean diameter of wear debris from braking events representative of urban driving is 6 microm, and the number-weighted mean is 1-2 microm for three currently used classes of lining materials: low metallic, semimetallic, and non-asbestos organic (NAO). In contrast, the wear rates are very material dependent, both in number and mass of particles, with 3-4 times higher emissions observed from the low metallic linings as compared to the semimetallic and NAO linings. Wind tunnel and test track measurements demonstrate the appearance of micron size particles that correlate with braking events, with approximately 50% of the wear debris being airborne for the test vehicle in this study. Elemental analysis of the wear debris reveals a consistent presence of the elements Fe, Cu, and Ba in both dynamometer and test track samples. PMID:14524436

  13. Synthesis and characterization of magneto-rheological (MR fluids for MR brake application

    Directory of Open Access Journals (Sweden)

    Bhau K. Kumbhar

    2015-09-01

    Full Text Available Magneto rheological (MR fluid technology has been proven for many industrial applications like shock absorbers, actuators, etc. MR fluid is a smart material whose rheological characteristics change rapidly and can be controlled easily in presence of an applied magnetic field. MR brake is a device to transmit torque by the shear stress of MR fluid. However, MR fluids exhibit yield stress of 50–90 kPa. In this research, an effort has been made to synthesize MR fluid sample/s which will typically meet the requirements of MR brake applications. In this study, various electrolytic and carbonyl iron powder based MR fluids have been synthesized by mixing grease as a stabilizer, oleic acid as an antifriction additive and gaur gum powder as a surface coating to reduce agglomeration of the MR fluid. MR fluid samples based on sunflower oil, which is bio-degradable, environmentally friendly and abundantly available have also been synthesized. These MR fluid samples are characterized for determination of magnetic, morphological and rheological properties. This study helps identify most suitable localized MR fluid meant for MR brake application.

  14. Modeling and Simulation of integrated steering and braking control for vehicle active safety system

    Directory of Open Access Journals (Sweden)

    Beibei Zhang

    2011-03-01

    Full Text Available Active chassis systems like braking, steering, suspension and propulsion systems are increasingly entering the market. In addition to their basic functions, these systems may be used for functions of integrated vehicle dynamics control. An experimental platform which aims to study the integration control of steering and braking is designed due to the research requirement of vehicle active safety control strategy in this paper. A test vehicle which is equipped with the systems of steer-by-wire and brake-bywire is provided and the Autobox, combined with Matlab/simulink and MSCCarsim, is used to fulfill the RCP (Rapid Control Prototyping and HIL (Hardware-in-loop. The seven-freedom vehicle model is constructed first and the approach of vehicle parameters estimation based on the Extended Kalman Filter (EKF is proposed. Testing the vehicle state through the sensor has its own disadvantage that the cost is high and easily affected by environment outside. To find a actual method of receiving the vehicle state using the ready-made sensors in vehicle, the researchers put forward various estimation method, of which have advantages and disadvantages. Based on the above, this paper applies the EKF to estimate the vehicle state, making the actual estimation come true. The primary control methods and controller designment is carried out to prove the validation of the platform.

  15. Braking of tearing mode rotation by ferromagnetic conducting walls in tokamaks

    International Nuclear Information System (INIS)

    An in-depth investigation of the braking of tearing mode rotation in tokamak plasmas via eddy currents induced in external ferromagnetic conducting structures is performed. In general, there is a “forbidden band” of tearing mode rotation frequencies that separates a branch of high-frequency solutions from a branch of low-frequency solutions. When a high-frequency solution crosses the upper boundary of the forbidden band, there is a bifurcation to a low-frequency solution, and vice versa. The bifurcation thresholds predicted by simple torque-balance theory (which takes into account the electromagnetic braking torque acting on the plasma, as well as the plasma viscous restoring torque, but neglects plasma inertia) are found to be essentially the same as those predicted by more complicated time-dependent mode braking theory (which takes inertia into account). Significant ferromagnetism causes otherwise electromagnetically thin conducting structures to become electromagnetically thick and also markedly decreases the critical tearing mode amplitude above which the mode “locks” to the conducting structures (i.e., the high-frequency to low-frequency bifurcation is triggered). On the other hand, if the ferromagnetism becomes too large, then the forbidden band of mode rotation frequencies is suppressed, and the mode frequency consequently varies smoothly and reversibly with the mode amplitude

  16. Active vibration control of multibody system with quick startup and brake based on active damping

    Institute of Scientific and Technical Information of China (English)

    TANG Hua-ping; TANG Yun-jun; TAO Gong-an

    2006-01-01

    A kind of active vibration control method was presented based on active damping and optimization design for driving load of multibody system with quick startup and brake. Dynamical equation of multibody system with quick startup and brake and piezoelectric actuators intelligent structure was built. The optimum driving load was calculated by applying the presented method. The self-sensing and self-tuning closed-loop active vibration control in quick startup and brake process was realized. The control algorithm, using local velocity negative feedback, i.e. the output of a sensor only affects the output of the actuator collocated, can induce damping effectively to actively suppress the system vibration. Based on the optimization design for driving load of multibody system with quick startup and bake, the active damping of piezoelectric actuators intelligent structure was used to farther suppress the vibration of system. Theoretical analysis and calculation of numerical show that the proposed method makes the vibration of system decrease more than the optimal design method for driving load of multibody system.

  17. 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.

  18. Rail temperature rise characteristics caused by linear eddy current brake of high-speed train

    Directory of Open Access Journals (Sweden)

    Xiaoshan Lu

    2014-12-01

    Full Text Available The rail temperature rises when the linear eddy current brake of high-speed train is working, which may lead to a change of rail physical characteristics or an effect on train operations. Therefore, a study concerning the characteristics of rail temperature rise caused by eddy current has its practical necessity. In the research, the working principle of a linear eddy current brake is introduced and its FEA model is established. According to the generation mechanism of eddy current, the theoretical formula of the internal energy which is produced by the eddy current is deduced and the thermal load on the rail is obtained. ANSYS is used to simulate the rail temperature changes under different conditions of thermal loads. The research result shows the main factors which contribute to the rising of rail temperature are the train speed, brake gap and exciting current. The rail temperature rises non-linearly with the increase of train speed. The rail temperature rise curve is more sensitive to the exciting current than the air gap. Moreover, the difference stimulated by temperature rising between rails of 60 kg/m and 75 kg/m is presented as well.

  19. Braking of Tearing Mode Rotation by Ferromagnetic Conducting Walls in Tokamaks

    Science.gov (United States)

    Fitzpatrick, Richard

    2015-11-01

    An in-depth investigation of the braking of tearing mode rotation in tokamak plasmas via eddy currents induced in external ferromagnetic conducting structures is performed. In general, there is a ``forbidden band'' of tearing mode rotation frequencies that separates a branch of high-frequency solutions from a branch of low-frequency solutions. When a high-frequency solution crosses the upper boundary of the forbidden band there is a bifurcation to a low-frequency solution, and vice versa. The bifurcation thresholds predicted by simple torque-balance theory (which takes into account the electromagnetic braking torque acting on the plasma, as well as the plasma viscous restoring torque, but neglects plasma inertia) are found to be essentially the same as those predicted by more complicated time-dependent mode braking theory (which takes inertia into account). Significant ferromagnetism causes otherwise electromagnetically thin conducting structures to become electromagnetically thick, and also markedly decreases the critical tearing mode amplitude above which the mode ``locks'' to the conducting structures (i.e., the high-frequency to low-frequency bifurcation is triggered). This research was funded by the U.S. Department of Energy under contract DE-FG02-04ER-54742.

  20. Electrophysiology-based detection of emergency braking intention in real-world driving

    Science.gov (United States)

    Haufe, Stefan; Kim, Jeong-Woo; Kim, Il-Hwa; Sonnleitner, Andreas; Schrauf, Michael; Curio, Gabriel; Blankertz, Benjamin

    2014-10-01

    Objective. The fact that all human action is preceded by brain processes partially observable through neuroimaging devices such as electroencephalography (EEG) is currently being explored in a number of applications. A recent study by Haufe et al (2011 J. Neural Eng. 8 056001) demonstrates the possibility of performing fast detection of forced emergency brakings during driving based on EEG and electromyography, and discusses the use of such neurotechnology for braking assistance systems. Since the study was conducted in a driving simulator, its significance regarding real-world applicability needs to be assessed. Approach. Here, we replicate that experimental paradigm in a real car on a non-public test track. Main results. Our results resemble those of the simulator study, both qualitatively (in terms of the neurophysiological phenomena observed and utilized) and quantitatively (in terms of the predictive improvement achievable using electrophysiology in addition to behavioral measures). Moreover, our findings are robust with respect to a temporary secondary auditory task mimicking verbal input from a fellow passenger. Significance. Our study serves as a real-world verification of the feasibility of electrophysiology-based detection of emergency braking intention as proposed in Haufe et al (2011 J. Neural Eng. 8 056001).

  1. 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.

  2. Application of Anti-slip/skid Re-adhesion Control System Based on Disturbance Observer to a Skid Control Considering Cooperation Control of Air Bake and Electric Brake

    Science.gov (United States)

    Kadowaki, Satoshi; Ohishi, Kiyoshi; Sano, Takashi; Yasukawa, Shinobu

    We have already proposed the anti-slip re-adhesion control based on disturbance observer and sensor-less vector control at acceleration mode. This paper proposes a new anti-skid re-adhesion control based on disturbance observer at braking mode. The numerical simulation and experimental results point out that the proposed anti-skid re-adhesion control system has the desired driving wheel torque response for the tested bogie system of electric train. An actual train uses both electric brake and air brake in the high-speed range. Hence, this paper proposes a new anti-skid re-adhesion control considering the air brake, which carries out the cooperation control of electric brake and air brake in order to realize a fine re-adhesion control. The numerical simulation results point out that the proposed system has the desired driving wheel torque response and a fine anti-skid re-adhesion control.

  3. THEORETICAL AND EXPERIMENTAL ANALYSIS OF LOADING IMPACT FROM THE PROGRESSIVE GEAR ON THE LIFT BRAKING DISTANCE WITH THE USE OF THE FREE FALL METHOD

    OpenAIRE

    Paweł Lonkwic; Patryk Różyło

    2016-01-01

    The gear which is the central safety element of the friction drive lift during braking is exposed to overloading connected with changeable weight which loads the lift braking system. In the article the results of numerical analysis for braking process of CHP 2000 type progressive gear distinguished by an innovative design have been presented. The numerical analysis was conducted with the use of a simulation of the gear roller displacement depending on changeable loading with the support of Ab...

  4. Constraining t-T conditions during palaeoseismic events - constraining the viscous brake phenomena in nature.

    Science.gov (United States)

    Dobson, Katherine J.; Kirkpatrick, James D.; Mark, Darren F.; Stuart, Finlay M.

    2010-05-01

    Melt generated by frictional heating during an earthquake is generally assumed to act as a lubricant, and decrease the frictional resistance to sliding. However, recent experimental [1] and theoretical [2] studies indicate that this might not always be the case. When the earthquake starts, melts form in isolated small patches along the fault, and only later coalesce into more extensive sheets. While the pockets of melt are isolated they have a high resistance to viscous shear and increase the overall strength of the fault: an effect known as the ‘viscous brake'. The experimental and theoretical data suggest that the melt pockets can actually stop an earthquake. The crucial parameter that controls if the viscous brake can operate is the normal stress working on the system, which is a function of the mass (i.e. the thickness) of rock above the rupture. It is impossible to directly observe or sample the earthquake source in active faults, and natural examples of the viscous brake have yet to be identified. We present a novel study that uses a combination of low temperature thermochronometry techniques to investigate the viscous brake in nature, by taking advantage of exhumed faults that preserve a record of ancient earthquakes; i.e pseudotachylytes. Pseudotachylytes are chilled frictional melts and are the only accepted indicator of ancient seismicity along faults. Pseudotachylytes found in the central part of the Sierra Nevada mountain range, California, are thin (indicate that the pseudotachylytes formed at temperatures of time-temperature cooling path of the host rock to be determined and the geothermal gradient to be assessed, which in turn allows us calculate the depth at which rupture occurred. We use these results to test the hypothesis that the Sierra Nevada pseudotachylyte acted as a viscous brake. This will ultimately improve understanding of earthquake ruptures by identifying an intrinsic control on the magnitude of earthquakes. References 1. Di Toro et

  5. Test Study on Assistant Braking Performance of Bus/Coach%客车辅助制动性能试验研究

    Institute of Scientific and Technical Information of China (English)

    周科

    2013-01-01

    The classification, function and principle of the assistant braking system of some coach are introduced. Through doing deceleration test to the assistant braking system of a coach based on the relative standard, the test data show that the braking performance of the retarder is superior to the engine braking system and the engine exhaust braking system, and the engine braking system or the engine exhaust braking system combined with the retarder can improve the braking performance of the coach braking in the high speed condition.%介绍客车辅助制动系统的分类、作用及原理。以某型客车为例,依据相关标准,采用减速度测定试验方法来测试样车的辅助制动性能。结果表明,缓速器制动的制动效能要优于发动机制动和发动机排气制动;采用发动机制动、发动机排气制动与缓速器联合工作的方式,能够有效地改善高速行车时的制动效能。

  6. Automotive airborne brake wear debris nanoparticles and cytokinesis-block micronucleus assay in peripheral blood lymphocytes: A pilot study.

    Science.gov (United States)

    Kazimirova, Alena; Peikertova, Pavlina; Barancokova, Magdalena; Staruchova, Marta; Tulinska, Jana; Vaculik, Miroslav; Vavra, Ivo; Kukutschova, Jana; Filip, Peter; Dusinska, Maria

    2016-07-01

    Motor vehicle exhaust and non-exhaust processes play a significant role in environmental pollution, as they are a source of the finest particulate matter. Emissions from non-exhaust processes include wear-products of brakes, tires, automotive hardware, road surface, and traffic signs, but still are paid little attention to. Automotive friction composites for brake pads are composite materials which may consist of potentially hazardous materials and there is a lack of information regarding the potential influence of the brake wear debris (BWD) on the environment, especially on human health. Thus, we focused our study on the genotoxicity of the airborne fraction of BWD using a brake pad model representing an average low-metallic formulation available in the EU market. BWD was generated in the laboratory by a full-scale brake dynamometer and characterized by Raman microspectroscopy, scanning electron microscopy, and transmission electron microscopy showing that it contains nano-sized crystalline metal-based particles. Genotoxicity tested in human lymphocytes in different testing conditions showed an increase in frequencies of micronucleated binucleated cells (MNBNCs) exposed for 48h to BWD nanoparticles (NPs) (with 10% of foetal calf serum in culture medium) compared with lymphocytes exposed to medium alone, statistically significant only at the concentration 3µg/cm(2) (p=0.032). PMID:27131798

  7. Diagnostic procedure on brake pad assembly based on Young's modulus estimation

    International Nuclear Information System (INIS)

    Quality control of brake pads is an important issue, since the pad is a key component of the braking system. Typical damage of a brake pad assembly is the pad–backing plate detachment that affects and modifies the mechanical properties of the whole system. The most sensitive parameter to the damage is the effective Young's modulus, since the damage induces a decrease of the pad assembly stiffness and therefore of its effective Young's modulus: indeed its variation could be used for diagnostic purposes. The effective Young's modulus can be estimated from the first bending resonance frequency identified from the frequency response function measured on the pad assembly. Two kinds of excitation methods, i.e. conventional impulse excitation and magnetic actuation, will be presented and two different measurement sensors, e.g. laser Doppler vibrometer and microphone, analyzed. The robustness of the effective Young's modulus as a diagnostic feature will be demonstrated in comparison to the first bending resonance frequency, which is more sensitive to geometrical dimensions. Variability in the sample dimension, in fact, will induce a variation of the resonance frequency which could be mistaken for damage. The diagnostic approach has been applied to a set of undamaged and damaged pad assemblies showing good performance in terms of damage identification. The environmental temperature can be an important interfering input for the diagnostic procedure, since it influences the effective Young's modulus of the assembly. For that reason, a test at different temperatures in the range between 15 °C and 30 °C has been performed, evidencing that damage identification technique is efficient at any temperature. The robustness of the Young's modulus as a diagnostic feature with respect to damping is also presented. (paper)

  8. Optimization of plastic injection molding process parameters for manufacturing a brake booster valve body

    International Nuclear Information System (INIS)

    Highlights: • PIM process parameters have been optimized for a brake booster valve body. • The Taguchi method and computer-aided engineering have been integrated and used. • Seven key parameters of PIM process have been considered. • A nearly 12% improvement have been found by using the optimal PIM process parameters. • The efficient improvement can improve the safety performance of a vehicle. - Abstract: The plastic injection molding (PIM) process parameters have been investigated for manufacturing a brake booster valve body. The optimal PIM process parameters is determined with the application of computer-aided engineering integrating with the Taguchi method to improve the compressive property of the valve body. The parameters considered for optimization are the following: number of gates, gate size, molding temperature, resin temperature, switch over by volume filled, switch over by injection pressure, and curing time. An orthogonal array of L18 is created for the statistical design of experiments based on the Taguchi method. Then, Mold-Flow analyses are performed by using the designed process parameters based on the L18 orthogonal array. The signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) are used to find the optimal PIM process parameters and to figure out the impact of the viscosity of resin, curing percentage, and compressive strength on a brake booster valve body. When compared with the average compression strength out of the 18 design experiments, the compression strength of the valve body produced using the optimal PIM process parameters showed a nearly 12% improvement

  9. Probability of failure of the waste hoist brake system at the Waste Isolation Pilot Plant (WIPP)

    International Nuclear Information System (INIS)

    In its most recent report on the annual probability of failure of the waste hoist brake system at the Waste Isolation Pilot Plant (WIPP), the annual failure rate is calculated to be 1.3E(-7)(1/yr), rounded off from 1.32E(-7). A calculation by the Environmental Evaluation Group (EEG) produces a result that is about 4% higher, namely 1.37E(-7)(1/yr). The difference is due to a minor error in the US Department of Energy (DOE) calculations in the Westinghouse 1996 report. WIPP's hoist safety relies on a braking system consisting of a number of components including two crucial valves. The failure rate of the system needs to be recalculated periodically to accommodate new information on component failure, changes in maintenance and inspection schedules, occasional incidents such as a hoist traveling out-of-control, either up or down, and changes in the design of the brake system. This report examines DOE's last two reports on the redesigned waste hoist system. In its calculations, the DOE has accepted one EEG recommendation and is using more current information about the component failures rates, the Nonelectronic Parts Reliability Data (NPRD). However, the DOE calculations fail to include the data uncertainties which are described in detail in the NPRD reports. The US Nuclear Regulatory Commission recommended that a system evaluation include mean estimates of component failure rates and take into account the potential uncertainties that exist so that an estimate can be made on the confidence level to be ascribed to the quantitative results. EEG has made this suggestion previously and the DOE has indicated why it does not accept the NRC recommendation. Hence, this EEG report illustrates the importance of including data uncertainty using a simple statistical example

  10. Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

    Science.gov (United States)

    Conti, R.; Galardi, E.; Meli, E.; Nocciolini, D.; Pugi, L.; Rindi, A.

    2015-05-01

    Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.

  11. Synthesis and characterization of magneto-rheological (MR) fluids for MR brake application

    OpenAIRE

    Bhau K. Kumbhar; Satyajit R. Patil; Suresh M. Sawant

    2015-01-01

    Magneto rheological (MR) fluid technology has been proven for many industrial applications like shock absorbers, actuators, etc. MR fluid is a smart material whose rheological characteristics change rapidly and can be controlled easily in presence of an applied magnetic field. MR brake is a device to transmit torque by the shear stress of MR fluid. However, MR fluids exhibit yield stress of 50–90 kPa. In this research, an effort has been made to synthesize MR fluid sample/s which will typical...

  12. Energy Management and Control of Electric Vehicles, Using Hybrid Power Source in Regenerative Braking Operation

    OpenAIRE

    Bo Long; Shin Teak Lim; Zhi Feng Bai; Ji Hyoung Ryu; Kil To Chong

    2014-01-01

    Today’s battery powered electric vehicles still face many issues: (1) Ways of improving the regenerative braking energy; (2) how to maximally extend the driving-range of electric vehicles (EVs) and prolong the service life of batteries; (3) how to satisfy the energy requirements of the EVs both in steady and dynamic state. The electrochemical double-layer capacitors, also called ultra-capacitors (UCs), have the merits of high energy density and instantaneous power output capability, and are...

  13. High torque, high impact braking system by using Hot Melt Adhesive (HMA)

    OpenAIRE

    Fernandez Bocanegra, Juan José

    2011-01-01

    When designing a new legged robot it is important to think about what the robot has to do. It is not the same a non-stop walking robot than a legged robot which has to be at the same position much longer than moving. For the second kind of robot, it could be a great improvement to add a break in each actuated joint, so it is not necesary to wasted energy during the stoped time. And not only that, thanks to the brake, it is possible to achive heavier loads using a speci c wal...

  14. Solitary Density Waves for Improved Traffic Flow Model with Variable Brake Distances

    Institute of Scientific and Technical Information of China (English)

    朱文兴; 丁瑞玲

    2012-01-01

    Traffic flow model is improved by introducing variable brake distances with varying slopes. Stability of the traffic flow on a gradient is analyzed and the neutral stability condition is obtained. The KdV (Korteweg-de Vries) equation is derived the use of nonlinear analysis and soliton solution is obtained in the meta-stable region. Solitary density waves are reproduced in the numerical simulations. It is found that as uniform headway is less than the safety distance solitary wave exhibits upward form, otherwise it exhibits downward form. In general the numerical results are in good agreement with the analytical results.

  15. A New, Low Braking Index For the LMC Pulsar B0540-69

    OpenAIRE

    Marshall, F. E.; Guillemot, L.; Harding, 39 A. K.; Martin, P.; Smith, D. A.

    2016-01-01

    We report the results of a 16-month monitoring campaign using the Swift satellite of PSR B0540-69, a young pulsar in the Large Magellanic Cloud. Phase connection was maintained throughout the campaign so that a reliable ephemeris could be determined, and the length of the campaign is adequate to accurately determine the spin frequency and its first and second derivatives. The braking index is 0.031 +/- 0.013 (90% confidence), a value much lower than previously reported for B0540-69 and almost...

  16. 车辆制动储能系统设计%Design of Vehicle Braking Energy Storage System

    Institute of Scientific and Technical Information of China (English)

    张玉宝; 金猛

    2013-01-01

    简述液压混合动力技术的产生背景、应用范围,提出基于汽车的制动性能设计混合动力液压系统的方案,设计储能系统,并对主要元件参数进行计算.通过仿真分析可以看出:制动过程平稳、制动能量回收好,系统设计与元件参数的计算合理.%The background and application scope of hydraulic hybrid technology were described.The idea of hybrid hydraulic system design based on car's braking performance was put forward.The main elements parameters were calculated.Simulation results show that the braking process is smooth,brake energy is recovered better,the system design and parameter calculation are reasonable.

  17. A METHOD OF CONSTRUCTING A MATRIX OF STATES OF THE DIAGNOSTIC PARAMETERS OF BRAKE SYSTEM OF A CAR

    Directory of Open Access Journals (Sweden)

    Uspensky I. A.

    2014-05-01

    Full Text Available The article describes the method of determining the list of rational diagnostic parameters of the brake system of a vehicle using the theory of probability and mathematical statistics. The problems determining the statistical probabilities of failures on objects considered a run; mathematical models (regression dependence the probability of failure of run; A statistical evaluation of the significance of the coefficients of regression models; verification has been made on the adequacy of the regression models; the probabilities of possible states of objects. On the basis of the construction and analysis of structural- effect model brake system information and calculates the importance of each monitored parameter using the notion of information entropy, determine the parameters to be diagnostic, and builds a matrix condition of brake systems for non-destructive testing, in order to move on maintenance and repair of the actual state

  18. Review of auxiliary braking technologies of Rigid%重型载货汽车辅助制动应用综述

    Institute of Scientific and Technical Information of China (English)

    侯永红; 王海金; 王瑞鑫; 黄建华; 郭成杰

    2015-01-01

    in order to improve the service life and braking ability of main brake for commercial rigid during frequent or prolonged braking, Using the auxiliary braking.Then the structure, working principle and braking performance of exhaust brake, engine brake, eddy current retarder and hydraulic retarder are expounded, and their advantages and disadvantages are compared, which is helpful to the development of rigid braking technology and the improvement of overall performance of rigid.%在重型载货汽车在频繁制动或长时间持续制动时,为了提高车桥制动器使用寿命和制动效能,采用了辅助制动系统。本文就目前在载货车上常用的发动机排气制动、发动机制动和液力缓速器辅助制动系统的结构与工作原理进行了介绍,并对比了几种辅助系统的优劣性,可以为后续载货车使用辅助制动系统性能的改进提供帮助。

  19. 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.

  20. Spontaneous-braking and lane-changing effect on traffic congestion using cellular automata model applied to the two-lane traffic

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2012-08-01

    Full Text Available In the real traffic situations, vehicle would make a braking as the response to avoid collision with another vehicle or avoid some obstacle like potholes, snow, or pedestrian that crosses the road unexpectedly. However, in some cases the spontaneous-braking may occur even though there are no obstacles in front of the vehicle. In some country, the reckless driving behaviors such as sudden-stop by public-buses, motorcycle which changing lane too quickly, or tailgating make the probability of braking getting increase. The new aspect of this paper is the simulation of braking behavior of the driver and presents the new Cellular Automata model for describing this characteristic. Moreover, this paper also examines the impact of lane-changing maneuvers to reduce the number of traffic congestion that caused by spontaneous-braking behavior of the vehicles.

  1. The new Mercedes-Benz decompression valve engine brake (DVB); Die neue Dekompressionsventil-Motorbremse (DVB) von Mercedes-Benz

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, T.; Holloh, K.D.; Fleckenstein, G.; Juergens, R.

    1995-07-01

    During recent years there has been a continuing increase in the demands for higher braking performance of commercial vehicle engines. Mercedes-Benz developed the engine brake with continuously open decompression valve (`Konstantdrossel`) and introduced it into series production in 1989 as an option. For the use on engines developed by Mercedes-Benz for foreign markets and for further improvements of vehicle safety investigations were made to increase the engine braking power even more. The further increase of braking power had to be achieved while retaining the additional decompression valve in the cylinder head. For this, the decompression valve was no longer kept open during the whole working cycle (continueously open decompression valve), but only for a short period from just before compression TDC to about 90 .. 120 crank angle after compression TDC (pulsed decompression valve). The hydraulic actuating system which opens and closes the decompression valves was developed in cooperation with Mannesmann-Rexroth GmbH, Lohr, Germany. The engine braking performance attainable with this system is shown in comparison to other known engine braking systems. The effects of the engine braking system on the downhill performance of commercial vehicles compared to other continuous braking systems are presented. (orig.) [Deutsch] In den letzten Jahren sind generell die Forderungen nach hoeherer Motorbremsleistung immer weiter gestiegen. Mercedes-Benz entwickelte die Konstantdrossel-Motorbremse und fuehrte sie 1989 in die Serie ein. Fuer den Einsatz an von Mercedes-Benz fuer aussereuropaeische Maerkte entwickelten Motoren und zur weiteren Erhoehung der Fahrzeugsicherheit wurde nach weiteren Moeglichkeiten zur Steigerung der Motorbremsleistung gesucht. Die Steigerung sollte unter Beibehaltung des zusaetzlichen Dekompressionsventils ermoeglicht werden. Dies wurde dadurch erreicht, dass das Dekompressionsventil nicht mehr waehrend des gesamten Arbeitsspiels konstant offen gehalten

  2. THE MOMENT OF UNSAFETY FOR DRIVING IN CONDITIONS OF POOR VISIBILITY TAKING INTO ACCOUNT THE EVALUATION OF VEHICLE BRAKING EFFICIENCY

    Directory of Open Access Journals (Sweden)

    A. Sarayev

    2014-02-01

    Full Text Available This study is aimed at investigation of a car collision with a pedestrian under limited visibility condi-tions. For this purpose an expert has to analyze the accident details and determine the critical time at which the car driver must take an action to avoid the collision. The analysis is complicated due to the fact that the vehicle is equipped with an anti-blocking braking system and does not leave a braking trace on the pavement. In this case, a relevant expert analysis technique does not exist. The development of such techniques as the basis of this scientific work is given.

  3. Towards Quark Deconfinement in Neutron Stars via Spindown: Gravitational Waves or Magnetic Braking?

    CERN Document Server

    Staff, Jan; Ouyed, Rachid

    2011-01-01

    A phase of interacting quark matter can arise inside the dense core of isolated neutron stars when they have been sufficiently spun down from their initial rapidly rotating configuration. In this work, we investigate the role of magnetic braking alongside r-mode driven gravitational wave emission in spinning down the neutron star towards quark deconfinement densities in its core. Employing different equations of state for the matter inside the star, we track its rotational evolution from birth and determine the minimum initial gravitational mass required to admit the subsequent appearance of quark matter in the core. Compared to earlier work by Staff et al. (2006), we find that r-mode driven spin-down begins to dominate magnetic braking for magnetic fields B<10^(14) Gauss, possibly leading to a faster transition to quark matter in these neutron stars. This effect is more pronounced for equations of state that are relatively stiff at high density. Using a prescribed approximate model for the r-mode evolutio...

  4. Weakened magnetic braking as the origin of anomalously rapid rotation in old field stars

    Science.gov (United States)

    van Saders, Jennifer L.; Ceillier, Tugdual; Metcalfe, Travis S.; Silva Aguirre, Victor; Pinsonneault, Marc H.; García, Rafael A.; Mathur, Savita; Davies, Guy R.

    2016-01-01

    A knowledge of stellar ages is crucial for our understanding of many astrophysical phenomena, and yet ages can be difficult to determine. As they become older, stars lose mass and angular momentum, resulting in an observed slowdown in surface rotation. The technique of ‘gyrochronology’ uses the rotation period of a star to calculate its age. However, stars of known age must be used for calibration, and, until recently, the approach was untested for old stars (older than 1 gigayear, Gyr). Rotation periods are now known for stars in an open cluster of intermediate age (NGC 6819; 2.5 Gyr old), and for old field stars whose ages have been determined with asteroseismology. The data for the cluster agree with previous period-age relations, but these relations fail to describe the asteroseismic sample. Here we report stellar evolutionary modelling, and confirm the presence of unexpectedly rapid rotation in stars that are more evolved than the Sun. We demonstrate that models that incorporate dramatically weakened magnetic braking for old stars can—unlike existing models—reproduce both the asteroseismic and the cluster data. Our findings might suggest a fundamental change in the nature of ageing stellar dynamos, with the Sun being close to the critical transition to much weaker magnetized winds. This weakened braking limits the diagnostic power of gyrochronology for those stars that are more than halfway through their main-sequence lifetimes.

  5. Modeling the Exo-Brake and the Development of Strategies for De-Orbit Drag Modulation

    Science.gov (United States)

    Murbach, M. S.; Papadopoulos, P.; Glass, C.; Dwyer-Cianciolo, A.; Powell, R. W.; Dutta, S.; Guarneros-Luna, A.; Tanner, F. A.; Dono, A.

    2016-01-01

    The Exo-Brake is a simple, non-propulsive means of de-orbiting small payloads from orbital platforms such as the International Space Station (ISS). Two de-orbiting experiments with fixed surface area Exo-Brakes have been successfully conducted in the last two years on the TechEdSat-3 and -4 nano-satellite missions. The development of the free molecular flow aerodynamic data-base is presented in terms of angle of attack, projected front surface area variation, and altitude. Altitudes are considered ranging from the 400km ISS jettison altitude to 90km. Trajectory tools are then used to predict de-orbit/entry corridors with the inclusion of the key atmospheric and geomagnetic uncertainties. Control system strategies are discussed which will be applied to the next two planned TechEdSat-5 and -6 nano-satellite missions - thus increasing the targeting accuracy at the Von Karman altitude through the proposed drag modulation technique.

  6. Mechanical braking system for the pulsed power supply system of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Highlights: ► Compact and innovative solution for dumping of large kinetic energy. ► Small mass of energy converter at the shaft due to circulating storage medium. ► Design of the active parts ensures flat torque/power characteristics. ► Also suitable for spending a great part of operating life in “Freewheeling” mode. -- Abstract: A few years ago, IPP reviewed the safety of the ASDEX Upgrade pulsed power supply system. Two critical sub-systems had been identified: The (electrical) braking system for the flywheel generators and the oil lubrication system for the shaft bearings. A simultaneous failure of these two systems may lead to severe damages and could have consequences for the safety of operating personnel. Therefore a second, independent braking possibility for every generator was stipulated. Especially the challenges adapting a dynamometer, originally designed for motor test benches, towards a plant safety system for generator EZ4 will be described in the paper. Further on, the paper will present the problems, implementing such a system into an existing installation, including the calculation of the required supporting structure, balancing of the extended shaft line and required water cooling and control. Finally it will report on the performance achieved during operation

  7. Mechanical braking system for the pulsed power supply system of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Käsemann, C.-P., E-mail: c.p.kaesemann@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Huart, M. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Michel Huart Personal Coaching and Consulting, Georgenschwaigstraße 23 RG, 80807 München (Germany); Stobbe, F.; Goldstein, I.; Sigalov, A. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Sachs, E. [Siemens AG, Industrial Automation Systems, Gleiwitzer Straße 555, 90475 Nürnberg (Germany); Perk, E. [Piper Test and Measurement Ltd., The Barn, Bilsington, Ashford, Kent TN25 7JT, England (United Kingdom)

    2013-10-15

    Highlights: ► Compact and innovative solution for dumping of large kinetic energy. ► Small mass of energy converter at the shaft due to circulating storage medium. ► Design of the active parts ensures flat torque/power characteristics. ► Also suitable for spending a great part of operating life in “Freewheeling” mode. -- Abstract: A few years ago, IPP reviewed the safety of the ASDEX Upgrade pulsed power supply system. Two critical sub-systems had been identified: The (electrical) braking system for the flywheel generators and the oil lubrication system for the shaft bearings. A simultaneous failure of these two systems may lead to severe damages and could have consequences for the safety of operating personnel. Therefore a second, independent braking possibility for every generator was stipulated. Especially the challenges adapting a dynamometer, originally designed for motor test benches, towards a plant safety system for generator EZ4 will be described in the paper. Further on, the paper will present the problems, implementing such a system into an existing installation, including the calculation of the required supporting structure, balancing of the extended shaft line and required water cooling and control. Finally it will report on the performance achieved during operation.

  8. Determination of aerobic work and power on a rope-braked cycle ergometer by direct measurement.

    Science.gov (United States)

    Gordon, Rae S; Franklin, Kathryn L; Baker, Julien S; Davies, Bruce

    2006-08-01

    The purpose of this study was to compare the power and work outputs of a cycle ergometer using the manufacturer's guidelines, with calculations using direct flywheel velocity and brake torque. A further aim was to compare the values obtained with those supplied by the manufacturer. A group of 10 male participants were asked to pedal a Monark 824E ergometer at a constant cadence of 60 r/min for a period of 3 min against a resistive mass of 3 kg. The flywheel velocity was measured using a tachometer. The brake force was determined by measuring the tension in the rope on either side of the flywheel. The calculated mean power was 147.45 +/- 6.5 W compared with the Monark value of 183 +/- 3.7 W. The difference between the methods for power estimation was 18% and was statistically significant (p < 0.01). The mean work done by the participants during the 3 min period was found to be 26 460 +/- 1145 J compared with the Monark value of 33,067 +/- 648 J (p < 0.01). The Monark formulae currently used to determine the power and work done by a participant overestimates the actual values required to overcome the resistance. There findings have far-reaching implications in the physiological assessment of athletic, sedentary, and diseased populations. PMID:16900228

  9. Particle Acceleration in Collapsing Magnetic Traps with a Braking Plasma Jet

    CERN Document Server

    Borissov, Alexei; Threlfall, James

    2016-01-01

    Collapsing magnetic traps (CMTs) are one proposed mechanism for generating non-thermal particle populations in solar flares. CMTs occur if an initially stretched magnetic field structure relaxes rapidly into a lower-energy configuration, which is believed to happen as a by-product of magnetic reconnection. A similar mechanism for energising particles has also been found to operate in the Earth's magnetotail. One particular feature proposed to be of importance for particle acceleration in the magnetotail is that of a braking plasma jet, i.e. a localised region of strong flow encountering stronger magnetic field which causes the jet to slow down and stop. Such a feature has not been included in previously proposed analytical models of CMTs for solar flares. In this work we incorporate a braking plasma jet into a well studied CMT model for the first time. We present results of test particle calculations in this new CMT model. We observe and characterise new types of particle behaviour caused by the magnetic stru...

  10. Real-time monitoring of brake shoe keys in freight cars

    Institute of Scientific and Technical Information of China (English)

    Rong ZOU; Zhen-ying XU; Jin-yang LI; Fu-qiang ZHOU

    2015-01-01

    Condition monitoring ensures the safety of freight railroad operations. With the development of machine vision technology, visual inspection has become a principal means of condition monitoring. The brake shoe key (BSK) is an important component in the brake system, and its absence will lead to serious accidents. This paper presents a novel method for automated visual inspection of the BSK condition in freight cars. BSK images are first acquired by hardware devices. The subsequent in-spection process is divided into three stages:first, the region-of-interest (ROI) is segmented from the source image by an im-proved spatial pyramid matching scheme based on multi-scale census transform (MSCT). To localize the BSK in the ROI, cen-sus transform (CT) on gradient images is developed in the second stage. Then gradient encoding histogram (GEH) features and linear support vector machines (SVMs) are used to generate a BSK localization classifier. In the last stage, a condition classifier is trained by SVM, but the features are extracted from gray images. Finally, the ROI, BSK localization, and condition classifiers are cascaded to realize a completely automated inspection system. Experimental results show that the system achieves a correct inspection rate of 99.2%and a speed of 5 frames/s, which represents a good real-time performance and high recognition accuracy.

  11. Stationary super-capacitor energy storage system to save regenerative braking energy in a metro line

    International Nuclear Information System (INIS)

    Highlights: ► Super-capacitors are used to store regenerative braking energy in a metro network. ► A novel approach is proposed to model easily and accurately the metro network. ► An efficient approach is proposed to calculate the required super-capacitors. ► Maximum energy saving is around 44% at off-peak period and 42% at peak period. ► Benefit/cost analyses are performed for the suggested ESS. - Abstract: In this paper, the stationary super-capacitors are used to store a metro network regenerative braking energy. In order to estimate the required energy storage systems (ESSs), line 3 of Tehran metro network is modeled through a novel approach, in peak and off-peak conditions based on the real data obtained from Tehran metro office. A useful method is proposed to predict the maximum instantaneous regenerative energy which is delivered to each station before applying ESS and based on that the ESS configuration for each station is determined. Finally, the effectiveness of the proposed ESS is confirmed by economic evaluations and benefit/cost analyses on line 3 of Tehran metro network.

  12. The effect of runway surface and braking on Shuttle Orbiter main gear tire wear

    Science.gov (United States)

    Daugherty, Robert H.; Stubbs, Sandy M.

    1992-10-01

    In 1988, a 1067 m long touchdown zone on each end of the Kennedy Space Center (KSC) Shuttle Landing Facility (SLF) was modified from its original heavy-broom finish with transverse grooves configuration to a longitudinal corduroy surface texture with no transverse grooves. The intent of this modification was to reduce the spin-up wear on the Orbiter main gear tires and provide for somewhat higher crosswind capabilities at that site. The modification worked well, so it was proposed that the remainder of the runway be modified as well to permit even higher crosswind landing capability. Tests were conducted at the NASA Langley Aircraft Landing Dynamics Facility (ALDF) to evaluate the merit of such a modification. This paper discusses the results of these tests, and explains why the proposed modification did not provide the expected improvement and thus was not implemented. Also, in an ongoing program to evaluate the origin of various tire wear phenomenon, a series of tests was conducted to evaluate the effect of braking on tire wear. Finally, a modified tire is discussed in terms of its wear performance under rollout and braking operations.

  13. Regression Test on the Rotational Speed between Two Loads as the Preparation for Braking System

    Science.gov (United States)

    Purwanti, B. S. R.; Yusivar, F.; K, I. Garniwa M.

    2013-04-01

    This paper is preparing the mathematic model of braking control, continuously of determination the error (e), delta error (de) of speed reduction [9]. Load-1 and Load-2 are driven by an electric motor located on the same shaft. Both loads are driven clock wise (CW), counter clock wise (CCW) by an asynchronous three-phase motor (M3). The mass of each load is also differentiated to simulate slip phenomena. Rotational speed of M3 is equal to Load-1, detected by Sensor-1, while speed rotation of Load-2 is detected by Sensor-2. The rotation for Load-1 and Load-2 can be adjusted on several position Hj (j = 1, 2, 3). Once Load-1 and Load-2 reach a constant speed, current source will be disconnected. Speed reduction from (ω±1475 rpm) to stagnant (ω=0 rpm) on Load-1 and Load-2 is considered time function. Data collected from both load (ω (t)) known as e, de; on each position of Hj. It uses covariance analysis to make sure that both loads are concurrent with each other against time difference. The objective of this research is to determine slip phenomena of speed reduction of each load. The expectations are to generate smoother braking and minimize the time needed when implemented with ANFIS.

  14. Regression Test on the Rotational Speed between Two Loads as the Preparation for Braking System

    International Nuclear Information System (INIS)

    This paper is preparing the mathematic model of braking control, continuously of determination the error (e), delta error (de) of speed reduction [9]. Load-1 and Load-2 are driven by an electric motor located on the same shaft. Both loads are driven clock wise (CW), counter clock wise (CCW) by an asynchronous three-phase motor (M3). The mass of each load is also differentiated to simulate slip phenomena. Rotational speed of M3 is equal to Load-1, detected by Sensor-1, while speed rotation of Load-2 is detected by Sensor-2. The rotation for Load-1 and Load-2 can be adjusted on several position Hj (j = 1, 2, 3). Once Load-1 and Load-2 reach a constant speed, current source will be disconnected. Speed reduction from (ω±1475 rpm) to stagnant (ω=0 rpm) on Load-1 and Load-2 is considered time function. Data collected from both load (ω (t)) known as e, de; on each position of Hj. It uses covariance analysis to make sure that both loads are concurrent with each other against time difference. The objective of this research is to determine slip phenomena of speed reduction of each load. The expectations are to generate smoother braking and minimize the time needed when implemented with ANFIS.

  15. Ergonomic assessment of brake and accelerator mechanisms of MF285 and MF399 tractors using electromyography method

    Directory of Open Access Journals (Sweden)

    A Nikkhah

    2016-04-01

    Full Text Available Introduction: Too many people are working in the agricultural sector and therefore, pay more attention to the safety and health at work in the agricultural sector is important. This issue is more important in developing industrial countries where the level of the ergonomic working condition is less than that of developed countries. Attention to ergonomic condition of agricultural machinery drivers is one of the goals of agricultural mechanization. Therefore, in this study the ergonomic conditions of brake and accelerator mechanisms for MF285 and MF399 tractor's drivers were investigated using a new method. Materials and Methods: 25 people were selected for experiment. The electrical activity of Medialis gastrocnemius, Lateralis gastrocnemius, Vastus medialis, Vastus lateralis, Quadratus Lumborum and Trapezius muscles of drivers before and during pressing the pedal and after rest time were recorded using Biovision device. Measurements were performed for each person on each muscle 30 seconds before pressing the pedal, 60 seconds after pressing the pedal and after 60 seconds of rest. For all drivers, the muscles on the right side (brake and accelerator side have been selected and tested. The measurements were performed in compliance with appropriate time intervals between the measurements. Results and Discussion: Ergonomic assessment of brake pedal: The results showed that the RMS electrical activity of muscles of Vastus medialis and Medial gastrocnemius, during 60 seconds braking were 2.47 and 1.97. So, Vastus medialis and Medial gastrocnemius had the highest stress during pressing the MF399 tractor's brake pedal. Moreover, the Medial gastrocnemius and Lateral gastrocnemius with RMS electrical activity ratio of 2.47 and 1.74 had the highest RMS electrical activity ratio respectively, during 60 seconds braking compared to before braking of MF285 tractor. The comparison of results showed that the Vastus medialis and Trapezius had the higher stress

  16. Effects of cooling rate on vermicular graphite percentage in a brake drum produced by one-step cored wire injection

    Directory of Open Access Journals (Sweden)

    Yu-shuang Feng

    2015-09-01

    Full Text Available In this research, a vermicular graphite cast iron brake drum was produced by cored wire injection in a one-step method. Silica sand and low-density alumina-silicate ceramic were used as molding materials in order to investigate the effect of cooling rate on percentage of vermicular graphite and mechanical properties of the brake drum casting. Several thermocouples were inserted into the casting in the desired positions to measure the temperature change. By means of one-step cored wire injection, the two residual concentrations of Mg and RE were effectively controlled in the ranges of 0.013%-0.017% and 0.019%-0.025%, respectively, which are crucial for the production of vermicular graphite cast iron and the formation of vermicular graphite. In addition, the cooling rate had a significant effect on the vermicular graphite percentage. In the case of the silica mold brake drum casting, there was an obvious difference in the cooling rate with the wall change, leading to a change in vermicular graphite percentage from 70.8% to 90%. In the low-density alumina-silicate ceramic mold casting, no obvious change in temperature was detected by the thermocouples and the percentage of the vermicular graphite was stable at 85%. Therefore, the vermicular graphite cast iron brake drum with a better combination of mechanical properties could be obtained.

  17. EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study.

    Science.gov (United States)

    Sonnleitner, Andreas; Treder, Matthias Sebastian; Simon, Michael; Willmann, Sven; Ewald, Arne; Buchner, Axel; Schrauf, Michael

    2014-01-01

    Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers' mental states during a primary driving task. N=20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers' mental states. Results show that reaction times and alpha spindle rate increased with time-on-task. Moreover, brake reaction times and alpha spindle rate were significantly higher while driving with auditory secondary task opposed to driving only. In single-trial classification, a combination of spindle parameters yielded a median classification error of about 8% in discriminating the distracted from the alert driving. Reduced driving performance (i.e., prolonged brake reaction times) during increased cognitive load is assumed to be indicated by EEG alpha spindles, enabling the quantification of driver distraction in experiments on public roads without verbally assessing the drivers' mental states. PMID:24144496

  18. Quantification of brake creep groan in vehicle tests and its relation with stick-slip obtained in laboratory tests

    Science.gov (United States)

    Neis, P. D.; Ferreira, N. F.; Poletto, J. C.; Matozo, L. T.; Masotti, D.

    2016-05-01

    This paper describes the development of a methodology for assessing and correlating stick-slip and brake creep groan. For doing that, results of tribotests are compared to data obtained in vehicle tests. A low velocity and a linear reduction in normal force were set for the tribotests. The vehicle tests consisted of subjecting a sport utility vehicle to three different ramp slopes. Creep groan events were measured by accelerometers placed on the brake calipers. The root mean square of the acceleration signal (QRMS parameter) was shown to be able to measure the creep groan severity resulting from the vehicle tests. Differences in QRMS were observed between front-rear and left-right wheels for all tested materials. Frequency spectrum analysis of the acceleration revealed that the wheel side and material type do not cause any significant shift in the creep groan frequency. QRMS measured in the vehicle tests presented good correlation with slip power (SP) summation. For this reason, SP summation may represent the "creep groan propensity" of brake materials. Thus, the proposed tribotest method can be utilized to predict the creep groan severity of brake materials in service.

  19. Arsenic bioavailability in the soil amended with leaves of arsenic hyperaccumulator, Chinese brake fern (Pteris vittata L.)

    NARCIS (Netherlands)

    Du, X.; Cui, Y.S.; Weng, L.P.; Cao, Q.; Yang Zhu, Yang

    2008-01-01

    An incubation experiment was carried out to better understand the fate of As during the decomposition of As-rich Chinese brake fern (Pteris vittata L.) leaves and to assess As bioavailability in soil. Dried fern leaves with an As concentration of 1,150 +/- 14 microg/g were amended with unpolluted so

  20. Model problem about evaluation of the temperature field in the uniformly rotating wheel at interaction with the disk brake

    OpenAIRE

    Anatolii I. Zadorozhnyi; Igor V. Kolesnikov

    2011-01-01

    In the article the axially symmetric mixed problem of heat conduction for a system «a wheel-disk brake» is considered. The solution is obtained by Fox method of average and method of joining of the solutions on a demarcation line between the boundary conditions.

  1. Model problem about evaluation of the temperature field in the uniformly rotating wheel at interaction with the disk brake

    Directory of Open Access Journals (Sweden)

    Anatolii I. Zadorozhnyi

    2011-05-01

    Full Text Available In the article the axially symmetric mixed problem of heat conduction for a system «a wheel-disk brake» is considered. The solution is obtained by Fox method of average and method of joining of the solutions on a demarcation line between the boundary conditions.

  2. An Insight to High Humidity-Caused Friction Modulation of Brake by Numerical Modeling of Dynamic Meniscus under Shearing

    Directory of Open Access Journals (Sweden)

    Liangbiao Chen

    2015-05-01

    Full Text Available To obtain an insight to high humidity-caused friction modulation in brake pad-rotor interface, the adhesion phenomenon due to a liquid bridge is simulated using an advanced particle method by varying the shearing speed of the interface. The method, called generalized interpolation material point for fluid-solid interactions (GIMP-FSI, was recently developed from the material point method (MPM for fluid-solid interactions at small scales where surface tension dominates, thus suitable for studying the partially wet brake friction due to high humidity at a scale of 10 m. Dynamic capillary effects due to surface tension and contact angles are simulated. Adhesion forces calculated by GIMP-FSI are consistent with those from the existing approximate meniscus models. Moreover, the numerical results show that capillary effects induce modulations of adhesion as slip speed changes. In particular, the adhesion modulation could be above 30% at low speed. This finding provides insights into how the high humidity-caused friction could cause modulations of brake, which are unable to be achieved by conventional models. Therefore, the numerical analysis helps to elucidate the complex friction mechanisms associated with brakes that are exposed to high humidity environments.

  3. SELF-REGULATION AND INTERNAL AND EXTERNAL PARAMETERS IN METAL BAND FRICTION PAIRS-SHOE BRAKES (PART 1

    Directory of Open Access Journals (Sweden)

    Volchenko N. A.

    2014-09-01

    Full Text Available We've illustrated self-regulation (based on the work function of the metal friction element and the regula-tion by quasiconstant unit loads on the contact patch of micropoints of metal-polymer friction pairs of band-block brake for the evaluation of process of their normal wear

  4. The braking force in walking: age-related differences and improvement in older adults with exergame training.

    Science.gov (United States)

    Maillot, Pauline; Perrot, Alexandra; Hartley, Alan; Do, Manh-Cuong

    2014-10-01

    The purposes of this present research were, in the first study, to determine whether age impacts a measure of postural control (the braking force in walking) and, in a second study, to determine whether exergame training in physically-simulated sport activity would show transfer, increasing the braking force in walking and also improving balance assessed by clinical measures, functional fitness, and health-related quality of life in older adults. For the second study, the authors developed an active video game training program (using the Wii system) with a pretest-training-posttest design comparing an experimental group (24 1-hr sessions of training) with a control group. Participants completed a battery comprising balance (braking force in short and normal step conditions), functional fitness (Senior Fitness Test), and health-related quality of life (SF-36). Results show that 12 weeks of video game-based exercise program training improved the braking force in the normal step condition, along with the functional fitness of lower limb strength, cardiovascular endurance, and motor agility, as measured by the Senior Fitness Test. Only the global mental dimension of the SF-36 was sensitive to exergame practice. Exergames appear to be an effective way to train postural control in older adults. Because of the multimodal nature of the activity, exergames provide an effective tool for remediation of age-related problems. PMID:24231655

  5. 汽车主动空气阻力制动系统仿真研究%Simulation study on initiative sir power brake system of the vehicle

    Institute of Scientific and Technical Information of China (English)

    付强; 赵立杰; 孙雪玲

    2012-01-01

    针对汽车防抱制动时地面制动力存在极限值无法更有效的缩减制动距离问题,提出了新型汽车主动空气阻力制动(APB)系统,分析其工作原理并进行控制模型基础仿真研究.阐述主动空气阻力制动系统理论可行性,依据压缩空气喷气助力原理的反作用应用于汽车制动系统,利用MATLAB/Simulink建立新型汽车制动系统动力学模型和APB仿真模型.设计了仿真试验,对比实施APB控制的车速与轮速曲线,试验结果表明APB控制达到缩减制动距离和制动时间的目的.%A new vehicle air power brake system (APB)is put forwarded in this paper to resolve that the braking distance can t be effective curtailed because of the maximum ground braking force during vehicle braking.Then its working principle and research on the basic simulation of control model is analyzed, in which the academic feasibility of initiative air power brake system is expatiatedAccording to the principle of compressed air power reaction against the brake system,a dynamics model of a new automotive brake system and simulation model of ABS+APB are established based on MATLAB/Simulink.i4/ierw/a/Y the simulated tests are designed to compare with the curve of vehicle speed and wheel velocity with APB, which result indicates that the cehicle speed and wheel velcocity controlled by APB can reduce braking distances and braking time.

  6. Design and Improvement of Automobile Exhaust Brake Valve%商用车排气制动阀设计改进

    Institute of Scientific and Technical Information of China (English)

    王钦明; 闫伟; 孙建军; 张志伟

    2016-01-01

    Based on the failure model effectiveness analysis of automobile exhaust brake valve products, this paper introduces the existing problems of the exhaust valve structure. The structure and function of the exhaust brake are effectively improved to ensure the reliability of the exhaust brake and working life.%通过对量产装车排气制动阀产品的失效模式分析,找到现有结构存在的问题,通过结构与功能改善,有效提高排气制动阀产品的寿命及可靠性。

  7. 动车组电空制动协调控制优化研究%Research on Optimization of Electro-pneumatic Braking Cooperative Control for EMU

    Institute of Scientific and Technical Information of China (English)

    朱琴跃; 包世炯; 谭喜堂; 王东响

    2013-01-01

    分析现有动车组电空制动控制系统中的制动力分配策略,针对动车与拖车电空制动力施加不均的问题,提出一种电空制动协调控制优化策略。采用动车电制动优先的控制原则,并根据载重反比分配拖车与动车所需施加的空气制动力。以 CRH2型动车组中一动一拖为基本单元,利用Matlab/Simulink软件对列车在不同制动工况进行仿真,结果表明,基于载重反比分配制动力的电空制动协调优化控制策略可有效提高列车制动效率,减小动车与拖车的车轮踏面磨损。%On analysis of the braking force distribution strategy in existing Electric Multiple Unit(EMU) electro-pneumatic braking control system, an optimization strategy of electro-pneumatic braking cooperative control is proposed, which aims at solving the imbalance problem of the motor car and trailer car’s electro-pneumatic braking. It uses electro-pneumatic braking priority control principle in EMU, and distributes air braking force of motor car and trailer car in inverse ratio on the basic of load. By modeling the EMU electro-pneumatic cooperative braking control and braking force distribution optimized algorithm while taking one motor car and one trailer car in CRH2 EMU as the basic unit, the Matlab/Simulink software is used to simulate different braking condition. The results indicate that the electro-pneumatic cooperative braking control optimization strategy which based on the load inverse-proportion for braking force distribution has the significant effect on improving brake efficiency, reducing wheel tread wear of the motor car and the trailer car.

  8. Estimation of the vehicle's centre of gravity based on a braking model

    Science.gov (United States)

    Yue, Hongwei; Zhang, Libin; Shan, Hongying; Liu, Huanfeng; Liu, Yicai

    2015-10-01

    A vehicle's centre of gravity (CG) is an important property that affects the vehicle's handing stability, ride comfort and safety. For example, a high CG may lead to a serious traffic accident due to the adverse effects it may have on roll and handling stability. In this paper, we develop a dynamic detection method to obtain vehicle's height that uses a simulation model based on a dynamic analysis during braking. Simulations show that the dynamic detection method is feasible. Experiments with three different vehicles are performed to verify the proposed method. The previously established prediction detection and lifting detection (LD) methods are used for comparison. The experimental results demonstrate that the proposed method has higher accuracy and efficiency than the LD method. Thus, the proposed method is useful for the vehicle detection.

  9. Collapse of Magnetized Singular Isothermal Toroids: II. Rotation and Magnetic Braking

    CERN Document Server

    Allen, A; Shu, F H

    2003-01-01

    We study numerically the collapse of rotating, magnetized molecular cloud cores, focusing on rotation and magnetic braking during the main accretion phase of isolated star formation. Motivated by previous numerical work and analytic considerations, we idealize the pre-collapse core as a magnetized singular isothermal toroid, with a constant rotational speed everywhere. The collapse starts from the center, and propagates outwards in an inside-out fashion, satisfying exact self-similarity in space and time. For rotation rates and field strengths typical of dense low-mass cores, the main feature remains the flattening of the mass distribution along field lines -- the formation of a pseudodisk, as in the nonrotating cases. The density distribution of the pseudodisk is little affected by rotation. On the other hand, the rotation rate is strongly modified by pseudodisk formation. Most of the centrally accreted material reaches the vicinity of the protostar through the pseudodisk. The specific angular momentum can b...

  10. 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...

  11. Discovery of Rotational Braking in the Magnetic Helium-Strong Star Sigma Orionis E

    CERN Document Server

    Townsend, R H D; Cohen, D H; Owocki, S P; ud-Doula, A

    2010-01-01

    We present new U-band photometry of the magnetic Helium-strong star Sigma Ori E, obtained over 2004-2009 using the SMARTS 0.9-m telescope at Cerro Tololo Inter-American Observatory. When combined with historical measurements, these data constrain the evolution of the star's 1.19 d rotation period over the past three decades. We are able to rule out a constant period at the p_null = 0.05% level, and instead find that the data are well described (p_null = 99.3%) by a period increasing linearly at a rate of 77 ms per year. This corresponds to a characteristic spin-down time of 1.34 Myr, in good agreement with theoretical predictions based on magnetohydrodynamical simulations of angular momentum loss from magnetic massive stars. We therefore conclude that the observations are consistent with Sigma Ori E undergoing rotational braking due to its magnetized line-driven wind.

  12. The Role of Magnetic Braking Effects on the Rotation of Subgiant and Giant Stars

    Science.gov (United States)

    Maciel, S. C.; de Freitas, D. B.; de Medeiros, J. R.

    2010-04-01

    The evolution of stars largely driven by rotation, controls a large number of internal and atmospheric stellar phenomena. In the present work we study the evolutionary behavior of stellar rotation along the HR Diagram, taking into account constraint conditions issued from recent observational survey of rotational velocity carried out with high precision procedures and new evolutionary codes. Theoretical predictions are presented for the evolutionary behavior of rotational velocity of solar-type giant and subgiant stars. We show that those simulations taking into account only the stellar evolutionary effects (increasing of moment of inertia) are unable to reproduce the observed rotational velocity of giant and subgiant stars. Different levels of magnetic braking appear to be acting on the rotation of evolved stars.

  13. DYNAMICS OF FREE STRAIGHT SWIMMING OF ANGULLA ANGULLA INCLUDING FORWARD, BRAKING AND BACKWARD LOCOMOTION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Eels can swim backward by reversing the direction of the traveling wave along the body. The propulsive mechanism of an eel, angulla angulla, during its self-propelled straight swimming, including forward swimming, braking and switching direction to backward swimming was numerically studied. The problem was reasonably simplified to a loose-coupling problem of fish swimming dynamics and hydrodynamics only in the swimming direction. The approach involved the simulation of the flow by solving the two-dimensional unsteady incompressible N-S equations and the fish motion dynamic problem with Newton's second law. Visualizations of flow fields and vortex structures were performed. The propulsive mechanism and dynamics during each process were investigated and the effects of controllable factors on forward free swimming were discussed.

  14. Steering Stability of a Bus Powered by Natural Gas While Braking

    Directory of Open Access Journals (Sweden)

    Ivan Ivković

    2011-03-01

    Full Text Available The use of natural gas as bus propellant presupposes the application of a driving unit adjusted to the use of natural gas in addition to the application of a corresponding gas facility. The first part of the paper describes the distinguishing features related to the storage of compressed natural gas tanks as the main carriers of additional mass due to the use of this energy substance for the propulsion of buses, as well as their effect on the structural features of vehicles. The second part of the paper covers the formulation and analysis of differential equations in terms of the steering system’s stability, and the equations depict the motion of the natural gas bus with its structural features, according to the defined models for instances of bus braking with locked front, rear and all wheels.

  15. MAGNETIC BRAKING FORMULATION FOR SUN-LIKE STARS: DEPENDENCE ON DIPOLE FIELD STRENGTH AND ROTATION RATE

    International Nuclear Information System (INIS)

    We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide range of relative magnetic field strengths and rotation rates, extending from the slow- and approaching the fast-magnetic-rotator regimes. Using the simulations to compute the angular momentum loss, we derive a semi-analytic formulation for the external torque on the star that fits all of the simulations to a precision of a few percent. This formula provides a simple method for computing the magnetic braking of Sun-like stars due to magnetized stellar winds, which properly includes the dependence on the strength of the magnetic field, mass loss rate, stellar radius, surface gravity, and spin rate, and which is valid for both slow and fast rotators.

  16. Optimization of actuator/sensor position of multi-body system with quick startup and brake

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new method was put forward to optimize the position of actuator/sensor of multi-body system with quick startup and brake. Dynamical equation was established for the system with intelligent structure of piezoelectric actuators. According to the property of the modes varying with time, the performance index function was developed based on the optimal configuration principle of energy maximal dissipation, and the relevant optimal model was obtained. According to its characteristic, a float-encoding genetic algorithm, which is efficient, simple and excellent for solving the global-optimal solution of this problem, was adopted. Taking the plane manipulator as an example, the result of numerical calculation shows that, after the actuator/sensor position being optimized,the vibration amplitude of the multi-body system is reduced by 35% compared with that without optimization.

  17. Arsenic speciation for the phytoremediation by the Chinese brake fern, Pteris vittata

    Institute of Scientific and Technical Information of China (English)

    R. Shoji; R. Yajima; Y. Yano

    2008-01-01

    Arsenic (As) speciation for the phytoremediation by the Chinese brake fern was studied. In particular, the mechanism of how plants induce compounds containing thiol (SH) and proteins by As exposure in terms of the relationship between As and phosphate uptaken into plant cells was examined. Pteris vittata callus could efficiently reduce As(V) to As(Ill) by the rapid introduction of reductase and synthesize thiols leading to phytoehelatins production. Furthermore, Pteris vittata could control phosphate concentration in the cells corresponding to the concentration of arsenite and arsenate. To our best knowledge, this is the first report to show the mechanisms of such high As tolerance of Pteris vittata using their callus in terms of in vitro approach for the analysis of As speciation and metabolism route.

  18. Effectiveness of low speed autonomous emergency braking in real-world rear-end crashes.

    Science.gov (United States)

    Fildes, B; Keall, M; Bos, N; Lie, A; Page, Y; Pastor, C; Pennisi, L; Rizzi, M; Thomas, P; Tingvall, C

    2015-08-01

    This study set out to evaluate the effectiveness of low speed autonomous emergency braking (AEB) technology in current model passenger vehicles, based on real-world crash experience. The validating vehicle safety through meta-analysis (VVSMA) group comprising a collaboration of government, industry consumer organisations and researchers, pooled data from a number of countries using a standard analysis format and the established MUND approach. Induced exposure methods were adopted to control for any extraneous effects. The findings showed a 38 percent overall reduction in rear-end crashes for vehicles fitted with AEB compared to a comparison sample of similar vehicles. There was no statistical evidence of any difference in effect between urban (≤60 km/h) and rural (>60 km/h) speed zones. Areas requiring further research were identified and widespread fitment through the vehicle fleet is recommended. PMID:25935427

  19. Ceramics for use in brakes and clutches; Keramik fuer den Einsatz in Bremsen und Kupplungen

    Energy Technology Data Exchange (ETDEWEB)

    Albers, A.; Arslan, A.; Herbst, D. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Maschinenkonstruktionslehre und Kraftfahrzeugbau

    2001-05-01

    A further increase in the power density of clutches and brakes is hardly possible using conventional friction materials. Although friction linings on the basis of sintered metals allow higher power densities than organic linings, they have serious disadvantages with regard to comfort, which means that they cannot be used in vehicles. The use of innovative ceramic materials here is promising, as is shown by the following article from the Institute of Machine Design and Automotive Engineering of the University of Karlsruhe. (orig.) [German] Eine weitere Steigerung der Leistungsdichte von Kupplungen und Bremsen ist mit herkoemmlichen Reibewerkstoffen fast nicht mehr moeglich. Reibbelaege auf der Basis von Sintermetallen erlauben eine hoehere Leistung als organische Reibbelaege, jedoch haben sie gravierende Nachteile in Bezug auf Komforteigenschaften, so dass sie im Pkw nicht eingesetzt werden koennen. Erfolg verspricht die Anwendung von neuartigen keramischen Werkstoffen, mit denen sich der folgende Aufsatz des Instituts fuer Maschinenkonstruktionslehre und Kraftfahrzeugbau der Universitaet Karlsruhe naeher befasst. (orig.)

  20. Evolution of intermediate-mass X-ray binaries driven by magnetic braking of Ap/Bp stars: I. ultracompact X-ray binaries

    CERN Document Server

    Chen, Wen-Cong

    2016-01-01

    It is generally believed that Ultracompact X-ray binaries (UCXBs) evolved from binaries consisting of a neutron star accreting from a low-mass white dwarf or helium star where mass transfer is driven by gravitational radiation. However, the standard white-dwarf evolutionary channel cannot produce the relatively long-period ($40 - 60$\\,min) UCXBs with high time-averaged mass-transfer rate. In this work, we explore an alternative evolutionary route toward UCXBs where the companions evolve from intermediate-mass Ap/Bp stars with an anomalously strong magnetic field ($100 - 10000$\\,G). Including the magnetic braking caused by the coupling between the magnetic field and an irradiation-driven wind induced by the X-ray flux from the accreting component, we show that intermediate-mass X-ray binaries (IMXBs) can evolve into UCXBs. Using the \\emph{MESA} code, we have calculated evolutionary sequences for a large number of IMXBs. The simulated results indicate that, for a small wind-driving efficiency $f=10^{-5}$, the a...