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Journal articles on the topic 'Brake friction coefficient'
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1
Sawczuk, Wojciech, Armando Miguel Rilo Cañás, Dariusz Ulbrich, and Jakub Kowalczyk. "Modeling the Average and Instantaneous Friction Coefficient of a Disc Brake on the Basis of Bench Tests." Materials 14, no. 16 (August 23, 2021): 4766. http://dx.doi.org/10.3390/ma14164766.
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This article presents the results of tests conducted on the average and instantaneous friction coefficients of railway vehicle disc brakes. The tests were carried out independently of various states of wear on the friction linings and the brake disc. The requirements of the International Union of Railways (UIC) regarding the approval of brake linings for use were taken into account. Based on many years of research using a brake bench to test railway disc brakes, the authors developed multiple regression models for the average friction coefficient and fluctuations (tolerances) in the instantaneous friction coefficient and achieved 870 results. The models proposed three types of variables: the input braking parameters (speed, pressure, and mass to be braked), operational parameters (the wear on the friction linings and the brake disc), and design parameters (perforations in the form of holes on the disc surface). The above two models were validated on the basis of 384 brakes, and in subsequent stages a further evaluation was performed. The coefficients were determined to be, respectively, 0.99 for the model of the average friction coefficient and 0.71 for the model of tolerance (fluctuations) of the instantaneous friction coefficient.
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Krivosheya, Yuriy Vladimirovich, and Tatyana Leonidovna Ripol-Saragosi. "Construct and energy reserves improvement of exploitative properties rail friction brake." Transport of the Urals, no. 2 (2020): 26–30. http://dx.doi.org/10.20291/1815-9400-2020-2-26-30.
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The paper gives an assessment of the design and energy reserves for improving the operational properties of the railway friction brake under the existing mass-dimensional restrictions and the growth of braking energy. The criterion for assessing the operational properties of the friction brake is the friction coefficient and contact energy load. The results of experimental studies of the relationship between the frictional characteristics of the disc brake and the affecting structural and loadspeed factors are presented. Design options for railway friction brakes are proposed that provide improved performance. A comparative analytical assessment of the contact energy load of new friction brake and classic disc brake options has been performed.
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Feier, Ioan, Joseph Way, and Rob Redfield. "Bicycle Disc Brake Thermal Performance: Combining Dynamometer Tests, Bicycle Experiments, and Modeling." Proceedings 49, no. 1 (June 15, 2020): 100. http://dx.doi.org/10.3390/proceedings2020049100.
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High-power bicycle disc braking can create excessive temperatures and boiling brake fluid, resulting in performance degradation and damage. The goal of this work is to understand brake friction performance and thermal behavior for bicycle disc brakes. A previously described disc braking dynamometer is used to assess brake pad performance of sintered metallic brake pads, organic brake pads, and ‘power’ organic pads in up to 400 W of braking power. The friction coefficient is found to be dependent on both temperature and normal force. Friction curve fits are provided for temperatures between 300 K and 550 K. Organic and ‘power’ organic pads are found to have similar behavior, and have higher friction coefficients compared to metallic pads. Further, brakes on an instrumented bicycle are tested in outdoor field trials during downhill descent. A MATLAB thermal model successfully predicts the downhill field brake disc temperatures when using the friction data curve fits.
4
Lee, Kwangjin. "Frictionally Excited Thermoelastic Instability in Automotive Drum Brakes." Journal of Tribology 122, no. 4 (December 29, 1999): 849–55. http://dx.doi.org/10.1115/1.1286207.
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Thermoelastic instability in automotive drum brake systems is investigated using a finite layer model with one-sided frictional heating. With realistic material properties of automotive brakes, the stability behavior of the one-sided heating mode is similar to that of the antisymmetric mode of two-sided heating but the critical speed of the former is higher than that of the latter. The effects of the friction coefficient and brake material properties on the critical speeds are examined and the most influential properties are found to be the coefficient of friction and the thermal expansion coefficient of drum materials. Vehicle tests were performed to observe the critical speeds of the drum brake systems with aluminum drum materials. Direct comparisons are made between the calculation and measurement for the critical speed and hot spot spacing. Good agreement is achieved when the critical speeds are calculated using the temperature-dependent friction material properties and the reduced coefficient of friction to account for the effect of intermittent contact. [S0742-4787(00)01503-4]
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Orłowicz, A. W., M. Mróz, G. Wnuk, O. Markowska, W. Homik, and B. Kolbusz. "Coefficient of Friction of a Brake Disc-Brake Pad Friction Couple." Archives of Foundry Engineering 16, no. 4 (December 1, 2016): 196–200. http://dx.doi.org/10.1515/afe-2016-0109.
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Abstract The paper concerns evaluation of the coefficient of friction characterising a friction couple comprising a commercial brake disc cast of flake graphite grey iron and a typical brake pad for passenger motor car. For the applied interaction conditions, the brake pressure of 0.53 MPa and the linear velocity measured on the pad-disc trace axis equalling 15 km/h, evolution of the friction coefficient μ values were observed. It turned out that after a period of 50 minutes, temperature reached the value 270°C and got stabilised. After this time interval, the friction coefficient value also got stabilised on the level of μ = 0.38. In case of a block in its original state, stabilisation of the friction coefficient value occurred after a stage in the course of which a continuous growth of its value was observed up to the level μ = 0.41 and then a decrease to the value μ = 0.38. It can be assumed that occurrence of this stage was an effect of an initial running-in of the friction couple. In consecutive abrasion tests on the same friction couple, the friction coefficient value stabilisation occurred after the stage of a steady increase of its value. It can be stated that the stage corresponded to a secondary running-in of the friction couple. The observed stages lasted for similar periods of time and ended with reaching the stabile level of temperature of the disc-pad contact surface.
6
Shinde, Dinesh Subhash, KN Mistry, and Mukesh Bulsara. "Theoretical and experimental investigation of non-asbestos friction lining material applied in automotive drum brake." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 6 (September 26, 2019): 972–85. http://dx.doi.org/10.1177/1350650119877775.
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Automotive brakes are the important machine element which provides an artificial frictional resistance to control the speed of an automobile. In the present work, theoretical models for the coefficient of friction between brake drum and friction liner are generated and simulated using MATLAB Simulink. A test set up designed and manufactured according to the brake lining quality test procedure (SAE J661) is used to investigate tribological properties of a non-asbestos friction lining material having 11 different constituents, which is manufactured from one of the brake liner manufacturer. An experiment is designed using response surface methodology (RSM) with vehicle speed, braking force, and sliding distance as the input parameters, whereas coefficient of friction and wear as an output. It is found that vehicle speed is the most significant parameter among the three. Fade and recovery behavior of the friction lining material is also studied and it is found that the developed friction lining material satisfies the criteria specified in SAE J661. Scanning electron microscope (SEM) and energy dispersive spectoscopy (EDS) have revealed the significant surface phenomenon.
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Triono, Agus, Wiratmaja Puja Ign, and Satryo Soemantri Brodjonegoro. "Modification of Pin on Disc Test to Measure Railway Brake Block Friction Coefficient." Key Engineering Materials 594-595 (December 2013): 639–43. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.639.
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One of the eligibility brakes requirements that used by railway is the fulfillment of the prescribed limit of friction coefficien. Test performed to determination railway brake block friction coefficient using pin on disc test. This test convert brake force into normal force on load cell that could be replace by balance. But due to the existing gap between arm force and brake force, error could be happened. To minimalized this error, that gap had to be reduced. In this research, the gap was reduced from 4.5 cm to 1 cm. Data recording was modified from manual recording into automatic recording using LabView program. This modified was very usefull because recording data could be done easily.
8
Sawczuk, Wojciech. "The Application of Vibration Accelerations in the Assessment of Average Friction Coefficient of a Railway Brake Disc." Measurement Science Review 17, no. 3 (June 1, 2017): 125–34. http://dx.doi.org/10.1515/msr-2017-0016.
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AbstractDue to their wide range of friction characteristics resulting from the application of different friction materials and good heat dissipation conditions, railway disc brakes have long replaced block brakes in many rail vehicles. A block brake still remains in use, however, in low speed cargo trains. The paper presents the assessment of the braking process through the analysis of vibrations generated by the components of the brake system during braking. It presents a possibility of a wider application of vibroacoustic diagnostics (VA), which aside from the assessment of technical conditions (wear of brake pads) also enables the determination of the changes of the average friction coefficient as a function of the braking onset speed. Vibration signals of XYZ were measured and analyzed. The analysis of the results has shown that there is a relation between the values of the point measures and the wear of the brake pads.
9
Venkata Padmanabhan, Adarsh, Hariram Ravichandran, Lokendra Pavan Kumar Pappala, and Shreyas Shenoy. "Friction Coefficient Mapping during Brake Interventions." SAE International Journal of Passenger Cars - Electronic and Electrical Systems 8, no. 1 (September 28, 2014): 8–13. http://dx.doi.org/10.4271/2014-01-2496.
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Gabidullin, A. E., D. V. Gorskiy, I. V. Nazarov, and V. A. Nikitin. "Calculation of the dependence of friction coefficient of locomotive composite ridge brake shoes on pressing force and braking speed." VNIIZHT Scientific Journal 79, no. 6 (February 27, 2021): 337–42. http://dx.doi.org/10.21780/2223-9731-2020-79-6-337-342.
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JSC “FRITEX” has developed non-asbestos ridge composite brake shoes UR 01-01 with a reduced coefficient of friction, which, in contrast to the cast iron ridge brake shoes currently used on locomotives, have high wear resistance and more stable frictional properties at high speeds. They are much lighter than traditional cast iron shoes, resulting in lower logistics costs and easier replacement by service departments. However, the new materials used for the production of the shoe, as well as its innovative design, which combines the two types of materials, require a detailed study of its frictional properties. For this, the braking modes of a locomotive equipped with UR 01-01 shoes were simulated in a full-scale unit of a brake mechanism on an inertial stand at fixed pressures and speeds. Based on the results of the experiments, the values of the friction coefficients of the brake shoes were determined and the dependence of the friction coefficient of the shoes on the pressing force and braking speed was established. The data obtained were used in braking calculations for an electric locomotive of the VL80 series, including the determination of the braking distance, holding a single locomotive by the parking brake on a slope, and ensuring the antiskid braking due to higher values of the friction coefficient of the UR 01-01 shoe at high speeds. The composite ridge brake shoe ensures compliance with the standard values of the braking distance, antiskid braking and slope parking for the VL80 series electric locomotive. In this case, the use of these composite shoes is possible without changes in the device of the lever transmission of the electric locomotive. It is necessary to conduct running brake tests to make approbation of obtained empirical dependence of the friction coefficient of new shoes on the pressing force and the braking speed of the locomotive and its widespread use in the calculation of brake systems.
11
Rievaj, Vladimír, Lenka Mokričková, and František Synák. "Temperature of the brakes and the Braking Force." Transport and Communications 5, no. 1 (2017): 13–16. http://dx.doi.org/10.26552/tac.c.2017.1.3.
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The kinetic energy of the braking vehicle is changed into heat and the resulting heat increases the temperature of each part of brakes. The changed temperature affects the coefficient of friction between the brake lining and brake drum of brake disc. Unless the brakes are actuated hydraulically there is the warning brake pads and brake fluid. Object of examination in this article is the impact of repetitive braking to change of these parameters and the impact of time to change the boiling point of the brake fluid.
12
Sugozu, Ilker, Ibrahim Can, and Cengiz Oner. "Investigation of using Calabrian pine cone dust and borax in brake pads." Industrial Lubrication and Tribology 66, no. 6 (September 2, 2014): 678–84. http://dx.doi.org/10.1108/ilt-03-2012-0029.
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Purpose – The purpose of this paper is to investigate use of calabrian pine (pinus brutia) cone (CPC) dust along with borax (BX) to assess the effect of friction coefficient. Despite the number of research studies completed on the mechanism of friction in automotive brake lining materials, the phenomenon is still not fully understood. Complex mechano-chemical processes occurring on the friction interface of a composite friction material make it difficult to understand the correlation between the formulation of brake lining and the frictional performance. Design/methodology/approach – In this study, the use of CPC dust along with BX has been investigated for assessing the effect on friction coefficient. CPC has resin in it. BX is a boron production which is widely used in boron glass production and in ceramic industry for increasing the heat- resistant and -forming abrasion resistant. Newly formulated brake lining material with five different ingredients has been tested under Friction Assessment and Screening Test. Friction coefficient, wear rate and scanning electron microscope for friction surface were examined to assess the performance of these samples. Findings – Analysis of the experimental results shows that the brake lining material containing CPC and BX significantly improved the stability of the friction coefficient, fade and wear resistance. Originality/value – Several investigations have been conducted to use different materials in brake pads. The brake pad standards have been provided in previous studies, as well as the aims for economical and sustainable production. In the present study, production of brake pads by CPC dust and BX has been executed. Parallel results have been presented between previously reported and present study, in view of brake characteristics and wear resistance. Use of the lower cost and productive organic sources of material are the main improvement of the present study.
13
Wang, Xin Hua, Si Wei Zhang, and De Guo Wang. "Research on Friction and Wear Performance of Brake Disc Pair Materials for New Type of Drilling Rig." Key Engineering Materials 373-374 (March 2008): 438–41. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.438.
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Tribological performance of new brake pair is studied at different temperatures, load and speed by variable temperature friction and wear test. The research indicates that brake pair has better frictional characteristics at variable temperature as well as heat-fade resistance performance at high temperatures. Wear rate of brake block and brake disc increases with friction temperature rising, however wear-resisting performance of brake disc is comparatively stable. Load has less influence on frictional coefficient of brake pair. Wear rate of brake disc and brake block increases with load increasing, but brake block has comparatively stable wear-resisting performance. Frictional coefficient of brake pair increases and tends to stabilize gradually along with sliding speed increasing, and speed has less influence on wear rate of brake block and brake disc. Initial heat-fading occurs in brake block material along with frictional temperature rising, secondary solidification may happen when frictional temperature reaches a certain value. When temperature rises much higher, brake block begins to soften and plastic flow intensifies, in addition thermal decomposition occurs in organic substance and wear-resisting performance becomes poorer. Build-up welding material has strong age-hardening effect and stable thermal structure, which leaves surface hardness and structure performance of brake disc unchanged at high temperatures.
14
Yin, Yan, Jiusheng Bao, Jinge Liu, Chaoxun Guo, Tonggang Liu, and Yangyang Ji. "Braking performance of a novel frictional-magnetic compound disc brake for automobiles." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 10 (August 3, 2018): 2443–54. http://dx.doi.org/10.1177/0954407018791056.
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Disc brakes have been applied in various automobiles widely and their braking performance has vitally important effects on the safe operation of automobiles. Although numerous researches have been conducted to find out the influential law and mechanism of working condition parameters like braking pressure, initial braking speed, and interface temperature on braking performance of disc brakes, the influence of magnetic field is seldom taken into consideration. In this paper, based on the novel automotive frictional-magnetic compound disc brake, the influential law of magnetic field on braking performance was investigated deeply. First, braking simulation tests of disc brakes were carried out, and then dynamic variation laws and mechanisms of braking torque and interface temperature were discussed. Furthermore, some parameters including average braking torque, trend coefficient and fluctuation coefficient of braking torque, average temperature, maximum temperature rise, and the time corresponding to the maximum temperature rise were extracted to characterize the braking performance of disc brakes. Finally, the influential law and mechanism of excitation voltage on braking performance were analyzed through braking simulation tests and surface topography analysis of friction material. It is concluded that the performance of frictional-magnetic compound disc brake is prior to common brake. Magnetic field is greatly beneficial for improving the braking performance of frictional-magnetic compound disc brake.
15
Tao, Ye Ying, Zhuo Yu Su, and Sheng Bao Lu. "A Study on Brake Noise Using the Complex Modal Analysis Method." Applied Mechanics and Materials 494-495 (February 2014): 42–46. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.42.
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The paper analyzed the influence of the friction factor theoretically on the brake system to produce noise, through complex modal analysis method, established the finite element model of air disc brake to analyze and forecast the brake noise and get brake noises frequency on a certain test conditions. Through the analysis of multiple sets of brake noise under different friction coefficient, it is concluded that the increase of friction coefficient has a promoting effect on brake noise.
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Wang, Zhi Jie, San Ming Liu, Lin Lin Luan, and Hua Qiao Xiao. "Study on the Influence of the Temperature Rise and Frictional Coefficient of Brake Shoe on Braking of Wind Turbine." Advanced Materials Research 443-444 (January 2012): 1045–49. http://dx.doi.org/10.4028/www.scientific.net/amr.443-444.1045.
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The value of brake friction coefficient have to do with temperature rises、speed、press and the influence of temperature rise is most large.Because high speed mine hoist come into being high temperature in apply the brake，it affect friction coefficient and capability of apply the brake system. therefore，unfold study brake temperature rise and friction coefficient forecast is very importance meaning.Because ANN can reflect non-line relation of input and output，this paper puts forward description mapping relation and effect to apply the brake safety of with temperature rises、speed、press and the influence.
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Riva, Gabriele, Francesco Varriale, and Jens Wahlström. "A finite element analysis (FEA) approach to simulate the coefficient of friction of a brake system starting from material friction characterization." Friction 9, no. 1 (August 14, 2020): 191–200. http://dx.doi.org/10.1007/s40544-020-0397-9.
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Abstract The coefficient of friction (COF) is one of the most important parameters to evaluate the performance of a brake system. To design proper brake systems, it is important to know the COF when estimating the brake force and resulting torque. It is challenging to simulate the COF since friction in disc brakes is a complex phenomenon that depends on several parameters such as sliding velocity, contact pressure, materials, and temperatures, etc. There is a lack of studies found in the literature focusing on simulation of the COF for a full brake system based on tribometer material characterization. The aim of this work is therefore to investigate the possibility to use a finite element analysis (FEA) approach combined with a COF pv-map to compute the global COF of a disc brake system. The local COF is determined from a pv-map for each local sliding velocity and contact pressure determined by the FEA. Knowing the local COF, the braking force of the entire brake system and the global COF can be evaluated. Results obtained by the simulation are compared with dyno bench test of the same brake system to investigate the validity of the simulation approach. Results show that the simulation is perfectly in line with the experimental measurements in terms of in-stop COF development, but slightly higher with a positive offset for every braking.
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Sokolski, Piotr, and Justyna Sokolska. "ASSESSMENT OF THE INFLUENCE OF THE COEFFICIENT OF FRICTION ON THE TEMPERATURE DISTRIBUTION OF A DISC BRAKE DURING THE BRAKING PROCESS." Tribologia 288, no. 6 (December 31, 2019): 95–99. http://dx.doi.org/10.5604/01.3001.0013.7774.
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Brake assemblies are key mechanisms in the aspect of safe and reliable operation of devices and machines. Due to intense thermal processes that occur during braking, the brakes are exposed to an accelerated wear. The article assesses the impact of tribological cooperation conditions between the caliper and the disc of a disc brake on the temperature of a disc. The variable value in the simulations was the coefficient of friction between the cooperating surfaces. A direct effect of the increase of the analysed parameter on the enhancement of brake elements’ temperature was found. At the same time, a similar nature of thermal processes was observed for all values of the friction coefficient taken into account.
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Bayram, Emre, and Ahmet Topuz. "Friction and wear properties of heavy load truck composite brake linings." Materials Testing 63, no. 1 (January 1, 2021): 79–84. http://dx.doi.org/10.1515/mt-2020-0011.
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Abstract Materials for friction used in brakes should fulfill many requirements, such as stable friction performance in all conditions, lower change in the friction coefficient, high wear resistance and low wear rate. In this study, three different compositions were produced to investigate the effects of each composition and its manufacturing parameters. Three different compositions, which are called standard, fly ash and sisal fiber mixture, were produced to be compared with existing commercial heavy-duty truck brake lining. These compositions were homogeneously mixed and hot molded at different pressures and temperatures. The post-curing effect was also investigated in some of the samples. The wear and friction tests were performed using a friction tester. The density and hardness of the samples were also analyzed in relation to compositions and manufacturing parameters. The coefficient of friction and wear behavior was compared with a commercial heavy-duty truck brake lining. The results suggest that there is a high potential in the samples investigated for commercial trucks applications of brake lining products that are highly suitable from the environmental and cost reduction view.
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Muzathik, A., Y. Nizam, M. Ahmad, and W. Nik. "The effect of boron on the performance of automotive brake." World Journal of Engineering 10, no. 6 (December 1, 2013): 523–28. http://dx.doi.org/10.1260/1708-5284.10.6.523.
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Friction material in an automotive brake system plays an important role for effective and safe brake performance. A single material has never been sufficient to solve performance related issues. Current research aimed to examine properties of Boron mixed brake pads by comparing them with the commercial brake pads. Friction coefficient of Boron mixed brake pads and commercial brake pads were significantly different and increased with the increase in surface roughness. The abrupt reduction of friction coefficient is more significant in commercial brake pad samples than in Boron mixed brake pad formulations. Fade occurred in commercial brake pad sample at lower temperatures. Boron formulations are more stable than their commercial counterparts.
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GAJEK, Andrzej, and Wojciech SZCZYPIŃSKI-SALA. "THE INFLUENCE OF THE SURFACE LAYER STRUCTURE IN DISC BRAKE PADS ON THEIR TRIBOLOGICAL PROPERTIES." Tribologia 267, no. 3 (June 30, 2016): 71–85. http://dx.doi.org/10.5604/01.3001.0010.7294.
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The article presents the results of the stand tribological investigation and microscopic observations of brake pad materials for automotive disc brakes. The reasons for the scatter of the friction coefficient value are analysed. The results of the brake pads’ friction surface topography observations and chemical constitution are presented. The investigations were carried out with scanning electron microscopy SEM and energy dispersive X-ray spectroscopy EDS. The point, line, and surface analysis of friction layer were done. The average contents of the chemical elements on the friction surface are presented. The heterogeneous nature of the structure on the friction layer was observed. The analysis has shown that brake pads with a compact structure of friction layer and large quantity components (10 components with more than 1% content each) had a smaller scatter of the coefficient of friction value in relation to the materials with a loose structure and less quantity components. The next part of the article presents the structure and geometric parameter products of the wear of the friction material. The problem concerning the quantity limitation of the wear particles entering the environment as dust was discussed.
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Wang, Dagang, Ruixin Wang, Tong Heng, Guozheng Xie, and Dekun Zhang. "Tribo-Brake Characteristics between Brake Disc and Brake Shoe during Emergency Braking of Deep Coal Mine Hoist with the High Speed and Heavy Load." Energies 13, no. 19 (September 30, 2020): 5094. http://dx.doi.org/10.3390/en13195094.
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The friction wear and thermal fatigue cracking of the brake shoe and friction-induced self-excited vibration (frictional flutter) of the disc brake can easily occur during emergency braking of a deep coal mine hoist with at high speed and with a heavy load. Therefore, tribo-brake characteristics between the brake disc and brake shoe during emergency braking of a deep coal mine hoist are investigated in the present study. Scaled parameters of the disc brake of a deep coal mine hoist are determined by employing the similarity principle. Friction tests between friction disc and brake shoe are carried out to obtain the coefficient of friction in the case of high speed and large specific pressure between the friction disc and brake shoe. Coupled thermo-mechanical finite element analyses of the brake disc and brake shoe are established to investigate temperature and stress fields of the brake disc and brake shoe during emergency braking, which is validated by the engineering failure case. Effects of braking parameters on flutter characteristics between the brake disc and brake shoe are explored by employing a double-degrees-of-freedom vibration mechanism model. The results show that the maximum temperature, equivalent Von Mises stress and contact pressure are all located at the average friction radii of contact surfaces of the brake disc and brake shoe during emergency braking. The cage crashing accident in the case of high speed and heavy load in a typical coal mine shows crack marks and discontinuous burn marks at central locations of brake shoe and brake disc surfaces, respectively, which indicates frictional flutter characteristics between brake disc and brake shoe. During emergency braking, flutter time duration decreases with increasing initial braking speed and damping parameter; the flutter amplitude and frequency of the disc brake increases with increasing normal braking load and stiffness, respectively.
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Huang, Yuan Mao, and J. S. Shyr. "On Pressure Distributions of Drum Brakes." Journal of Mechanical Design 124, no. 1 (November 1, 1999): 115–20. http://dx.doi.org/10.1115/1.1427694.
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Based on the assumptions that there is perfect contact at the interface between the brake drum and the lining plates, the friction coefficient is constant, the thermal effect is neglected, and the brake drum is a rigid body, the pressure distributions of drum brakes were studied by using the boundary element method. The constant element is used in the two-dimensional model of the drum brake for simplicity and economy. The friction force versus the effective lift at the actuation edge and the location of the maximum pressure are compared and indicate a good correlation with existing data. The effects of the Young’s modulus of elasticity of the metal shoe, the arc lengths of the metal shoe and lining plate, the location, the thickness, the friction coefficient, the Young’s modulus of elasticity of the lining plate, and the angle of actuation force on the pressure distributions were then studied. By selecting proper values of these parameters, a drum brake can be designed to have a more uniform pressure distribution and a longer life.
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Zhang, Yong Hui, Zhi Chao Xiao, Jian Feng Yang, Ji Ping Wang, and Zhi Hao Jin. "Preparation of C/C-SiC Brake Materials with Low Cost and High Friction Performance." Materials Science Forum 620-622 (April 2009): 421–24. http://dx.doi.org/10.4028/www.scientific.net/msf.620-622.421.
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C/C-SiC brake materials were prepared by improved chemical liquid vaporized infiltration (CLVI) combined with liquid silicon infiltration (LSI) process, which needed less than thirty hours. The microstructure and frictional properties of the material were investigated. The density and porosity of the C/C-SiC brake material were 2.05 g/cm3 and 4.8%, respectively. The average dynamic friction coefficient of the materials was about 0.36, and the friction coefficient was stable. The average linear wear rate was less than 4.7 µm cycle-1 for rotating and stationary disk. The matrix composition and microstructure resulted in the high frictional performances.
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Gerlici, Juraj, and Tomáš Lack. "Rail Vehicles Brake Components Test Bench Utilisation." Applied Mechanics and Materials 486 (December 2013): 379–86. http://dx.doi.org/10.4028/www.scientific.net/amm.486.379.
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Reduction of noise due to rolling contact of wheel and rail for fright cars is one of the principal tasks of the European railways to be solved. Experts of railways, industries and universities were engaged during the last about ten years to search for technical solutions. An important noise reduction of fright cars can be achieved by replacing the cast iron brake shoes by composite brake shoes. Doing that, two directions have been taken into consideration. This is due to the fact, that at that time most composite brake shoes were based on friction coefficients were far away from that ones of the cast iron brake shoes. Applying such friction materials on existing vehicles would have as a consequence the change of braking forces acting on the wheels. These types of brake shoes (K-block) show a friction coefficient which is higher than that one of cast iron. As a consequence the application of the silent composite brake blocks of type K affords the adaptation of the braking system of the vehicle, what is cost intensive. For these reason, the application of K-brake block was proposed for new built vehicles. For existing vehicles solutions having the same friction coefficient as the cast iron brake shoes were requested (LL-Brake doing in this way, the modification of the braking equipment of existing fright cars could be avoided.
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Meng, Xian Jie. "Numerical Investigation of the Influence of Friction Coefficient on Brake Groan." Applied Mechanics and Materials 44-47 (December 2010): 1923–27. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.1923.
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A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the stability of vibration system at the equilibrium points is analyzed using the nonlinear dynamics theory. Finally the numerical method is taken to study the impacts of friction coefficient on brake groan. The calculation result shows that with the increase of kinetic friction coefficient /or the decrease of difference value between static friction coefficient and kinetic friction coefficient can prevent or restrain self-excited vibration from happening.
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Borawski, Andrzej. "Conventional and unconventional materials used in the production of brake pads – review." Science and Engineering of Composite Materials 27, no. 1 (November 17, 2020): 374–96. http://dx.doi.org/10.1515/secm-2020-0041.
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AbstractBrakes are one of the most important components of vehicle. The brake system must be reliable and display unchanging action throughout its use, as it guards the health and life of many people. Properly matched friction pair, a disc and brake pad (in disc brakes), have a great impact on these factors. In most cases, the disc is made of grey cast iron. The brake pads are far more complex components. New technologies make it possible to develop materials with various compositions and different proportions, and connect them permanently in fully controllable processes. This elaboration shows that all these factors have a greater or lesser impact on the coefficient of friction, resistance to friction wear and high temperature, and brake pad’s operating life. This review collects the most important, the most interesting, and the most unconventional materials used in production of brake pads, and characterizes their impact on the tribological properties of pads.
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Kchaou, Mohamed, Amira Sellami, Jamal Fajoui, Recai Kus, Riadh Elleuch, and Frédéric Jacquemin. "Tribological performance characterization of brake friction materials: What test? What coefficient of friction?" Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, no. 1 (March 25, 2018): 214–26. http://dx.doi.org/10.1177/1350650118764167.
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This article describes and explains the tribological tests and methods for the evaluation of the performance of the brake friction materials. It starts by discussing the particularities of these materials and the variation of characterization tests, which can experimentally simulate many aspects of brake situation but with a large field of tribo-test, from standard to specific protocol. Examples of preparation, procedures, instrumentation, and analysis results for the tribological aspect testing ranging from the scale of vehicle braking performance (by methods including inertia dynamometers, Krauss testing, friction assessment screening test, and Chase testing) to simplified test using reduced-scale prototypes for small-sample friction, are explained. A particular attention is attributed to the discussion of the viability of the friction coefficient report in relation to the material properties and brake compound performance. At the end of this article, the guarantee of the performance output or ranking evaluated by such experimental methods is discussed.
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Bao, Jiusheng, Yan Yin, Lijian Lu, and Tonggang Liu. "Tribological characterization on friction brake in continuous braking." Industrial Lubrication and Tribology 70, no. 1 (January 8, 2018): 172–81. http://dx.doi.org/10.1108/ilt-09-2016-0205.
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Purpose The purpose of this study is to establish an effective method for characterizing the tribological properties of friction brakes during continuous braking because they have direct influences on the reliable operation of transport vehicles and industrial equipments. Design/methodology/approach First, tribological tests were carried out with the X-DM type friction tester, and changing curves of friction coefficient and temperature were obtained. Second, a novel tribological characteristic parameter set characterizing the tribological properties of brake pair in continuous braking was extracted from some important experimental data such as friction coefficient, wear rate and temperature. Finally, the influence of law and mechanism of braking number on dynamic tribological parameters was studied through continuous braking experiments. Findings The extracted tribological characteristic parameter set includes two subsets: dynamic characteristic parameter subset and overall characteristic parameter subset, which is composed of ten parameters: dynamic parameters of friction coefficient (including average, trend coefficient and stability coefficient), dynamic wear rate, dynamic average temperature, dynamic temperature rise, overall average friction coefficient, overall wear rate, overall average temperature and overall temperature rise. Originality/value Conclusively, the novel tribological characteristic parameter set is more comprehensive and objective, and it can provide a theoretical basis for the study of tribological properties in continuous braking.
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Su, Zhu Yu. "A Study on Forming Mechanism of Braking Torque on the Friction Surface." Advanced Materials Research 850-851 (December 2013): 200–203. http://dx.doi.org/10.4028/www.scientific.net/amr.850-851.200.
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The process of vehicle brake, the influence of the temperature on brake friction directly determines the braking force and the frictional coefficient, and has a huge impact on the braking torque. Based on the characteristics of frictional material, combining with modeling and simulation tests, researching the basic theory of braking technology, contribute to the stability and enhancement of braking performance.
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Sugozu, ilker, ibrahim mutlu, and Kezban Banu Sugozu. "The effect of colemanite on the friction performance of automotive brake friction materials." Industrial Lubrication and Tribology 68, no. 1 (February 8, 2016): 92–98. http://dx.doi.org/10.1108/ilt-04-2015-0044.
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Purpose – The purpose of this paper is to investigate use of colemanite (C) upon friction and wear performance of automotive brake lining. Brake lining production with the boron product colemanite addition and braking characterization investigated for development of non-asbestos organic (NAO) brake lining because of negative effects on human health and environmental hazard of asbestos containing linings. During the braking, brake lining is warmed up extremely due to friction, and the high temperature causes to decreasing of breaking performance. Colemanite has high melting temperature, and this makes this material valuable for brake lining. Design/methodology/approach – This study investigated the effect of colemanite (C) upon friction and wear performance of automotive brake lining. Based on a simple experimental formulation, different amounts of boron product colemanite were used and then evaluated using a friction assessment and screening test. In these specimens, half of the samples (shown with H indices) were heat treated in 4 h at 180°C temperature. Friction coefficient, wear rate and scanning electron microscope for friction surfaces were used to assess the performance of these samples. Findings – The results of test showed that colemanite can substantially improve properties of friction materials. The friction coefficient of friction materials modified with colemanite varies steadily with the change of temperature, and the wearing rate of friction materials is relatively low by using colemanite. Heat treatment-applied samples (CH) have provided a higher and stable friction coefficient. These results indicate that colemanite has ideal application effect in various friction materials. Originality/value – This paper fulfils an identified information and offers practical help to the industrial firms working with brake lining and also to the academicians working on wear of materials. Parallel results have been presented between previously reported and present study, in view of brake characteristics and wear resistance. Use of the lower cost and productive organic sources of material are the main improvement of the present study.
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KOVALENKO, Pavel, and Svetlana PEREPELKINA. "INVESTIGATION OF DYNAMIC FRICTION COEFFICIENT IN BRAKE SYSTEMS." Proceedings on Engineering Sciences 1, no. 1 (May 2019): 330–34. http://dx.doi.org/10.24874/pes01.01.042.
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Wang, Xiaoyang, Jiusheng Bao, Jinge Liu, Yan Yin, Tonggang Liu, and Shaodi Zhao. "Preparation and optimization of a soft magnetic brake friction material based on permalloy additive." Industrial Lubrication and Tribology 73, no. 2 (January 29, 2021): 308–15. http://dx.doi.org/10.1108/ilt-04-2020-0124.
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Purpose This paper aims to develop of magnetic field controlled friction braking technology, a novel brake friction material with magnetic was designed and prepared in this paper. Design/methodology/approach The permalloy, a soft magnetic material, was selected as an additive to design and prepare the magnetic brake material. The friction, wear performance and permeability of each brake pads were investigated by experiments. By choosing the performance of friction coefficient fluctuation, friction coefficient deviation and mean wear rate as optimization parameters, the formulation of the magnetic friction material was optimized based on Fuzzy theory by using analytic hierarchy process methods and SPSS software. Findings The results showed that the developed soft magnetic friction material has not only superior friction coefficient, permeability and inferior wear rate but also good physical and mechanical properties. Originality/value Permalloy powder was added to the formulation of friction material to achieve a new functional friction material with high magnetic permeability. It is believed that this research will be of great theoretical and practical significance to develop both new brake materials and active control technology of the braking process in the future.
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Zhang, Lijun, Wenbo Li, and Dejian Meng. "Influence of Heterogeneous Contact Stiffness and Heterogeneous Friction Coefficient on Frictional Squeal." Shock and Vibration 2018 (2018): 1–21. http://dx.doi.org/10.1155/2018/6379201.
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Contact stiffness and friction coefficient are excitation sources and key influencing factors to frictional squeal with obvious inhomogeneous characteristic that is always neglected. In this paper, a multipoint contact flexible pin-on-disc system is established considering tangential stiffness. Then influence of contact stiffness and friction coefficient with heterogeneous distribution on frictional squeal is studied using the complex modal analysis. The research shows that contact stiffness and friction coefficient heterogeneities influence the likelihood of occurrence of the squeal, the frequency of the squeal, and the real part of the complex eigenvalue of the system. And when the contact stiffness and friction coefficient are close to the boundary of the region of mode-coupling instability, flexible pin-on-disc system with homogeneous contact stiffness and friction coefficient cannot predict whether frictional squeal occurs or not. Besides, uncertain distribution of contact stiffness and friction coefficient can induce the uncertainty of brake squeal.
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Natarajan, M. P., and B. Rajmohan. "Heat Dissipation and Temperature Distribution of Brake Liner Using Steady State Analysis." Applied Mechanics and Materials 249-250 (December 2012): 712–17. http://dx.doi.org/10.4028/www.scientific.net/amm.249-250.712.
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Brakes are machine elements that absorb kinetic energy in the process of slowing down or stopping a moving part. Brake capacity depends upon the unit pressure between the braking surfaces, the coefficient of friction, and the ability of the brake to dissipate heat equivalent to the energy being absorbed. In braking system, drum brake is used mostly for automotive application. During the braking process, the forces and pressures in a drum brake are difficult to determine because of the manner in which the shoe contacts the drum. Finite Element analysis has been used to predict interface temperatures and heat flows and the results have been compared with experimental measurements made using fine thermocouples. Good agreement has been achieved, showing that the proportion of heat which flows into the friction material varies with time and temperature.
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Nandiyanto, Asep Bayu Dani, Siti Nur Hofifah, Gabriela Chelvina Santiuly Girsang, Silmi Ridwan Putri, Bentang Arief Budiman, Farid Triawan, and Abdulkareem Sh Mahdi Al-Obaidi. "The Effects of Rice Husk Particles Size as A Reinforcement Component on Resin-Based Brake Pad Performance: From Literature Review on the Use of Agricultural Waste as A Reinforcement Material, Chemical Polymerization Reaction of Epoxy Resin, to Experiments." Automotive Experiences 4, no. 2 (May 24, 2021): 68–82. http://dx.doi.org/10.31603/ae.4815.
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This study aims to investigate the effect of rice husks’ particle size on resin-based brake pad performance (i.e. compressive strength, puncture strength, mass loss, wear rate, friction coefficient, and heat resistance). Bisphenol A-epichlorohydrin and cycloaliphatic amine were mixed to form resin and used as the brake pad's base material. In the experiment, rice husk with a specific particle size (i.e., 250, 500, dan 1000 μm) was added to the resin. Rice husk has received considerable interest due to its lignin, cellulose, and silica content, making it suitable as friction material due to its ceramic-like behavior. The experimental results showed small rice husk particles improved compressive strength, puncture strength, and bulk density. This can be obtained from the analysis of the maximum compressive strength for brake pad supported by particles with sizes of 250, 500, and 1000 μm having values of 0.238; 0.173; and 0.144 MPa, respectively. In contrast, large particles formed coarse surfaces and pores, decreased mass loss rate, and improve friction properties (i.e. wear rate, friction coefficient). The friction coefficient values of brake pad supported by particles with sizes of 250, 500, and 1000 µm were, respectively, 0.2075; 0.2070; and 0.3379. Particle size affected interpacking, interfacial bonding, pores number and size, thermal softening, mechanical properties, and friction properties of the brake pad. Comparison between the prepared resin-based and commercial brake pad was also done, confirming the utilization of agro-waste as a potential alternative for friction material in the brake pad.
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Liu, Yu, Jie Hao, Panli Kang, Zhihua Sha, Fujian Ma, Dapeng Yang, and Shengfang Zhang. "Research on dynamic characteristics of compensation mechanism for large-power wind turbine disc brake." Multidiscipline Modeling in Materials and Structures 16, no. 3 (January 3, 2020): 595–605. http://dx.doi.org/10.1108/mmms-03-2019-0056.
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Purpose The purpose of this paper is to establish a rigid–flexible coupling model of wind turbine disc brake to simulate the actual working condition of the wind turbine brake and to study the dynamic characteristics of the compensation mechanism under different friction coefficients and braking force. It provides reference for the structure design and optimization of the compensation mechanism (compensation brake wear) in the wind turbine brake. Design/methodology/approach Based on multi-body contact dynamics theory, the rigid‒flexible coupling dynamic model of wind turbine brakes with compensation mechanism is established, in which the contact process of the components in the compensation mechanism and the phenomenon of rotation and return are described dynamically, and the rotation angle of the compensation nut and the axial displacement response of the compensation screw are calculated under different parameters. Findings The analysis results show that the braking reliability of the brake compensation mechanism can be effectively improved by increasing the friction coefficient of threads or increasing the friction of push rod contact surface; increasing the braking force can also improve the reliability of brake compensation mechanism, but when the braking force comes over a critical value, the effect of braking force on the reliability of the brake is very small. The braking test verifies the effectiveness of the simulation results. Originality/value Analyzing the influence of compensation mechanism on braking reliability in the braking process is of great practical significance for improving the braking efficiency and process safety of wind turbine brake.
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Huynh, Le Hong Thai, and Pavel Němeček. "Sensitivity Analysis and Optimization Disc Brake by Stress Constraints." Applied Mechanics and Materials 52-54 (March 2011): 583–88. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.583.
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In recent years, a lot of studies on brake of car aims to reduce stress, vibration and noise of the brake on vehicle. In this paper presents a sensitivity analysis of pressure and friction coefficient effect to stress of disc brake. Base on this result, an optimization for brake by stress constraints was performed. The results are shown that the contact area between disc brake and pad also it’s stress and pressure. Studies also have shown relationships between pressure, friction coefficient and stress of brake. After that, we optimize the model of disc brake by stress constraints to obtain the new model better. This is a pre study for studies on dynamic and vibration of disc brake.
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Zhang, Hai Tao, Ying Jun Dai, Yu Jing Jia, and Guang Zhen Cheng. "The Design of Disc Brake for Mine Hoist in Civil Engineering." Advanced Materials Research 568 (September 2012): 212–15. http://dx.doi.org/10.4028/www.scientific.net/amr.568.212.
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This article will describe the research status and the features of control system of the disc brakes of mine hoist. The disc brakes consist of body, outer cylinder, cylinder, piston, ring, disc springs, plunger, gate disk and other components. The disc brakes use the pre-load of disc springs to force the piston to move towards the brake disc, push the brake pads out, then the brake pads and drum brake disc contact and resulting in positive pressure, then the formation of friction produce a braking torque. When the brake system loose pads, the cylinder is filled with the pressure oil, which make the piston compresses the disc springs, and promote the brake pads to move back and then left brake disc, remove the braking force. The hydraulic circuit of the braking system chooses two-way parallel oil and four oil cylinder brake. A slip road set up a one-way throttle, making the slip road brake slightly delayed, which will achieve two stage braking and make work more stable. This disc brake is normally closed, which means when the hoist does not work, the brake is in the state of braking to prevent the occurrence of accidents. This brake is safe, reliable and sensitive in action. The materials of brake pads is rigid asbestos plastic, which have stable friction coefficient, good wear resistance, is not sensitive to the aqueous medium and salt spray,it has flexible installation location, and it is easy to use, adjust and maintain.
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LIEW, K. W., and N. S. M. EL-TAYEB. "THE EFFECT OF ROTOR DISC MATERIAL ON TRIBO BEHAVIOR OF AUTOMOTIVE BRAKE PAD MATERIALS." Surface Review and Letters 15, no. 05 (October 2008): 625–33. http://dx.doi.org/10.1142/s0218625x08011925.
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This work aims to investigate the effect of two different counterdisc materials, i.e. gray cast iron (GCI) and ductile gray cast iron (DGCI) on tribo behavior of non-commercial frictional materials (NF1, NF2, NF4, and NF5) and two other chosen commercial brake pads (CMA and CMB) under dry sliding contact conditions. The four non-commercial frictional materials were fabricated with various percentages of phenolic binder resin (15 and 20 vol.%) and reinforced with steel fibers (15 and 20 vol.%) using hot press molding methods. Tribo tests were carried out using a small-scale tribo-tester of pad-on-disc type. Friction coefficient and wear of non-commercial and commercial brake pads were measured against each counterdisc (GCI and DGCI) and compared. Then, the friction and wear characteristic are discussed by comparing the experimental results obtained for each kind of cast iron. The results showed that maximum friction coefficient (0.4–0.5) of brake pad was attained at 2.22 MPa applied pressure and 2.1 m/s sliding speed when the frictional brake pad materials were tested against DGCI disc rotor. Meanwhile, similar wear rates for all frictional brake pad materials were sustained at higher applied pressure and sliding speed when tested against either type of rotor discs (GCI and DGCI). The results on the other hand, indicated that non-commercial materials NF1 and NF4, gave better wear resistance compared to other frictional pad materials. NF2 exhibited the lowest wear resistance when tested against GCI and DGCI rotor disc at all applied pressure and sliding speeds. The latter result is referred to the low percentage binder resin in the friction material NF2.
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Zhang, Shao Yang, and Fu Ping Wang. "Frictional Performance of Brake Pads against Al Metal Matrix Composites with Different Sizes of SiC Particles." Key Engineering Materials 336-338 (April 2007): 1743–45. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.1743.
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Two drums suitable for a Chase Machine were made of Al metal matrix composites containing 25vol.% SiCp with 3.5 μm and 34 μm in nominal diameter respectively. The same brake pads were measured on the Chase Machine installing each individual drum. It has been found that the brake pads had better frictional performance and wear resistance against the drum with the large-size SiCp than against the drum with the small-size ones. Friction fade took place at elevated temperatures - above 316 oC, but the original level of friction coefficient could be regained rapidly upon cooling with regard to the latter. The minor level of friction coefficient was attributable to soft Al crystal structure characteristics and thick tribofilms during the testing stages.
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Yevtushenko, Aleksander A., and Piotr Grzes. "Initial Selection of Disc Brake Pads Material based on the Temperature Mode." Materials 13, no. 4 (February 11, 2020): 822. http://dx.doi.org/10.3390/ma13040822.
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A spatial computational model of a motor vehicle disc brake, based on the system of equations of heat dynamics of friction and wear (HDFW), was developed. The interrelations of temperature-dependent coefficient of friction and coefficient of intensity of wear through the contact temperature and vehicle velocity were taken into account. The solution of the system of equations of HDFW was obtained by the finite element method (FEM) for six different brake pad materials associated with the cast-iron disc during a single braking. Changes in the braking time, coefficient of friction, braking torque, vehicle velocity, mean temperature of the contact area of the pads with the disc and wear of the friction surfaces were determined. Then, the obtained calculation results were evaluated in terms of stabilization of the coefficient of friction (braking torque), as well as minimization of the maximum temperature, wear, braking time and pads mass. As a result, recommendations were given to select optimum brake pad material in combination with a cast-iron disc.
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Zeng, Ming, Chun Wei, Xue Mei Xiong, and Chuan Bai Yu. "Frictional Brake Material Reinforced with Sisal Fiber and Glass Fiber Hybrid." Advanced Materials Research 150-151 (October 2010): 284–87. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.284.
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Asbestos-free frictional material is developed by using phenol formaldehyde resins modified with nano- SiO2 as matrix while surface-treated sisal fiber and glass fiber are used as reinforcement. The friction and wear properties were investigated on Constant speed (D-SM) tester. The abrasion surfaces of composites were observed by scanning electron microscope (SEM). Test result shows that all the properties, such as, friction coefficient and wear can meet the GB5763-2008 requirement. When the sisal fiber and glass fiber hybrid ratio is 2:1, the composite has the high mechanical property, suitable and stable coefficient of friction and relatively low wearability especially at high temperature.
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Huang, Jinchun, Charles M. Krousgrill, and Anil K. Bajaj. "An Efficient Approach to Estimate Critical Value of Friction Coefficient in Brake Squeal Analysis." Journal of Applied Mechanics 74, no. 3 (June 13, 2006): 534–41. http://dx.doi.org/10.1115/1.2423037.
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Automotive brake squeal generated during brake applications has become a major concern in automotive industry. Warranty costs for brake noise related complaints have been greatly increasing in recent years. Brake noise and vibration control are also important for the improvement of vehicle quietness and passenger comfort. In this work, the mode coupling instability mechanism is discussed and a method to estimate the critical value of friction coefficient identifying the onset of brake squeal is presented. This is achieved through a sequence of steps. In the first step, a modal expansion method is developed to calculate eigenvalue and eigenvector sensitivities. Different types of mode couplings and their relationships with possible onset of squeal are discussed. Then, a reduced-order characteristic equation method based on the elastically coupled system eigenvalues and their derivatives is presented to estimate the critical value of friction coefficient. The significance of this method is that the critical value of friction coefficient can be predicted accurately without the need for a full complex eigenvalue analysis, making it possible to determine the sensitivity of system stability with respect to design parameters directly.
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Al-Osaimy A. S., Al-Osaimy A. S. "Influence of Tread Width of the Brake Pedal Pads on the Friction Coefficient Generated by Bare Foot and Footwear Soles." journal of King Abdulaziz University Engineering Sciences 23, no. 1 (January 12, 2012): 227–45. http://dx.doi.org/10.4197/eng.23-1.10.
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The present work discusses the effect of the treads width of the rubber brake pedal pads on the friction coefficient. Measurement of friction coefficient generated by bare foot and rubber footwear soles sliding against the brake pedal pads of different treads width in dry, sand contaminated, water and oil lubricated conditions is discussed. Experiments of the sliding of bare foot against the rubber pedal pad showed that friction coefficient of dry sliding significantly decreased with increasing tread width. The sliding direction has no effect on the friction coefficient for the tested pads. In the presence of sand particles separating the two contact surfaces, load had no influence on friction coefficient. Friction coefficient slightly decreased with increasing tread width. For water wetted pedal pad, friction coefficient displayed higher values than that observed for the condition of presence of sand particles. Friction values showed consistent trend with increasing the tread width. Friction displayed by oil lubricated pedal pads was the lowest and the sliding condition could be considered as unsafe.
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Wang, Wen Yan, Gao Lu, Jing Pei Xie, and Jia Xi Wang. "Research of Friction and Wear Performance of Large Truck’s Brake Drum." Advanced Materials Research 503-504 (April 2012): 601–5. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.601.
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In this research, different frictions were settled to study the wear resistance of HT250, RuT15, RuT75 and QT500 according to the wear failure situation in automobile brake drum. And the relationship between wear mechanism, microstructure and mechanical properties were discussed. It can be seen from the friction and wear experiment that, under different friction and wear conditions, both of RuT35 and QT500 have the best wear resistance property while HT250 has the worst wear resistance property. With the increase of lord, the brake torque and friction coefficient of RuT35 stays unchangeable, showing well brake ability. With the increase of lord, the brake ability of HT250 was getting better, while QT500 showing the opposite. SEM was used to analyze the wear morphology, the results show that: the abrasive wear and adhesion wear are presented mainly. HT250 has a bad surface quality while QT500 and RuT15 have a bad surface quality. Generally speaking, RuT15 is the best material to made brake drum, in the consideration of were resistance and braking stability.
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Li, Shaohua, Jiangbo Chen, and Hongwei Huang. "Investigation on Emergency Brake Property of a Heavy-Duty Vehicle Based on Functional Virtual Prototyping Model." Open Mechanical Engineering Journal 8, no. 1 (December 31, 2014): 675–81. http://dx.doi.org/10.2174/1874155x01408010675.
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A Functional Virtual Prototyping full vehicle model for a tri-axial heavy-duty truck is built, and the non-linearity of suspension dampers and tires is also considered. With the trajectory of full vehicle gravity center, longitudinal tire force of front wheel, longitudinal acceleration, lateral acceleration, yaw rate and pitch angle as the evaluation indexes of brake property, the influences of system parameters including wheelbase, load shift, road surface roughness and separated road friction coefficient on brake efficiency, stability and ride comfort are analyzed. In addition, the interaction of brake and full vehicle dynamics is studied. Results show that small wheelbase and load shift may improve the brake efficiency of vehicles, small road surface roughness is beneficial to brake stability and ride comfort, and great frictional coefficient difference of separation road will worsen the brake efficiency and stability.
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Demirhan, Yusuf Ziya, and Recai Kus. "Investigation of Friction Coefficient for Twaron-Reinforced Brake Shoe Materials." Materials Science Forum 909 (November 2017): 106–10. http://dx.doi.org/10.4028/www.scientific.net/msf.909.106.
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After the adverse effects of asbestos used in brake shoes on vehicles were come up, the researches on ecological shoe material have been carried out by many researchers. From this point forth, four different twaron-reinforced composite materials, which could be brake shoes, were produced in this study. Samples were produced in double acting press at a pressure of 100 MPa at 160°C by mixing the components used in powder form in a mixer. The samples were cured at 160°C for 6 hours. After curing, produced samples and those taken from commercial shoes were compared by performing hardness pin-on-disc wear tests (ASTM G99-95). When the results are evaluated in terms of hardness, it was observed that 20% twaron-reinforced sample has the highest hardness (116,88 Rockwell-R), but when evaluated in terms of friction, it was seen that while 5% twaron-reinforced sample satisfies highest friction coefficient, 10% twaron-reinforced sample exhibits close values to the commercial brake shoe at varying loads and showed a stable friction performance.
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Ouyang, Qiu Bao, H. L. Gu, W. L. Wang, Di Zhang, and Guo Ding Zhang. "Friction and Wear Properties of Aluminum Matrix Composites and its Application." Key Engineering Materials 351 (October 2007): 147–50. http://dx.doi.org/10.4028/www.scientific.net/kem.351.147.
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Friction and wear properties of aluminum matrix composites are studied, including brake speed, brake pressure, and surface temperature etc. A conclusion can be drawn that SiC particle reinforced aluminum matrix composites are of stable friction coefficient, high thermal conductivity, and excellent wear-resistance. Hubs of motorcycle with brake rings of Al/SiC composites were manufactured and exhibited an excellent braking performance.
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Asif, Mohammad, Kamlesh Chandra, and Prabhu Shankar Misra. "Wear Characteristic of Al-Based Metal Matrix Composites Used for Heavy Duty Brake Pad Applications." Materials Science Forum 710 (January 2012): 407–11. http://dx.doi.org/10.4028/www.scientific.net/msf.710.407.
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Wear study of metal matrix composites used as friction material is one of the most important parameter for determining the brake performance. The present investigations relates to the development of Aluminum powder based brake pads; where the back plates are also made of Aluminum based powders respectively. Thus it is aimed to fabricate net-shape Aluminium powder based brake pads in a single forming operation with better characteristics (low wear, low temperature rise, stable coefficient of friction) employing a newly developed technology namely “Hot Powder Preform Forging” technique. Three Aluminum based friction composites which are designated as ALM 01, ALM 02 & ALM 03 were formulated. The dry wear test is carried out using a pin-on-disc tribo-tester at constant sliding speed of 9 ms-1 under a load of 50 N. The counter face disc is made of heat treated grey cast iron. During the test, the cumulative wear (gm), Coefficient of friction, temperature rise (oC) and noise level (dB) were recorded. The effect of load at constant speed on sliding wear, frictional characteristic of aluminum based MMC (rotor / drum) in dry condition is studied. On the basis of initial laboratory tests like density, Hardness, wear test, the samples were qualified for sub-scale dynamometer test at Rejected Take Off condition. Optical microscope was used to investigate the microstructure of metal matrix friction composites surfaces. The results revealed that coefficient of friction was more stable. The Cumulative wear (gm) was low with rise in temperature. It was also observed that distribution of ingredients in matrix was fine and homogeneous.