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Researchers have long been studying the effects of the modification of friction material compositions on their tribological properties. Predictive models have also been developed, but they are of limited use in the design of new compositions. Therefore, this research aims to investigate the tribological behaviour of single ingredients in friction materials to develop a tribological dataset. This dataset could then be used as a foundation for a cellular automaton (CA) predictive model, intended to be a tool for designing friction materials. Tribological samples were almost entirely composed of four distinct friction material ingredients, and one sample composed of their mixture was successfully produced. Pin-on-disc (PoD) tribometer testing and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDXS) analysis were used for the tribological characterization. Each material showed distinct tribological properties and evolution of the contact surface features, and the synergistic effect of their mutual interaction was also demonstrated by their mixture. [ABSTRACT FROM AUTHOR]

Currently, most electromechanical brake (EMB) schemes are only suitable for passenger cars, and their maximum clamping force is insufficient to satisfy the braking demands of commercial vehicles. Additionally, previous studies on clamping force control are largely based on an EMB equipped with sensors. Due to constraints in installation space and cost, sensorless EMBs are gradually gaining attention. Furthermore, accurately identifying the contact point between the friction lining and the brake disc is the promise of clamping force control for sensorless EMBs. Hence, a sensorless EMB scheme suitable for commercial vehicles is proposed in this study. Secondly, a dynamics model of the EMB actuator is established. After a comprehensive analysis of the proposed EMB actuator, a clamping force control strategy considering the contact points between the friction lining and the brake disc is proposed. Finally, simulation analyses of the strategy are carried out. The results show that the axial length of the proposed EMB actuator is shortened by 17.6% compared with a mainstream pneumatic disc brake. Furthermore, the proposed method can accurately identify the contact points between the friction lining and the brake disc, and the proposed control strategy enables the EMB actuator to achieve the fast response, accurate tracking, and stable maintenance of the target clamping force. [ABSTRACT FROM AUTHOR]

While many techniques have been proposed to enhance heat dissipation in ventilated disc brakes during extended braking, solid disc brakes have received less attention, particularly under hard braking conditions. This study investigates the transient thermal responses of both solid and ventilated disc brakes during single-stop braking. Numerical simulations were conducted on three disc types: Solid, ventilated with 32 fins, and ventilated with 42 fins, each made from different materials: Grey cast iron, AISI 420, and INCONEL 718. The simulations assessed the maximum surface temperature and the temperature distribution across the disc thickness. The results indicate significant differences in thermal performance based on material properties and disc design. Grey cast iron exhibited the lowest maximum temperatures due to its high thermal conductivity, whereas INCONEL 718 showed the highest temperatures due to its lower thermal conductivity. Despite their improved cooling capabilities, ventilated discs demonstrated higher maximum surface temperatures compared to solid discs, due to their lower thermal capacity. These findings highlight the importance of material selection and structural design in optimizing brake disc performance under high thermal loads. [ABSTRACT FROM AUTHOR]

The system parameters of the braking process of a rotary eddy current brake (RECB) exhibit time-varying characteristics and alternate transformations of the heat source (HS) and non-heat source (NHS) regions of the brake disc. A full-structure equivalent thermal network model for the RECB system is established, considering its physical structure. In addition, a calculation method is proposed to update the temperature of the rotating unit with a finite stepping distance. The method employs the transient process of electromagnetic thermal coupling on the brake disc, distinguishes between the thermal processes in the HS and NHS regions of the brake disc, and simulates the temperature distribution of the entire braking system. The proposed calculation method is verified via rig tests, and the effects of brake temperature rise on braking performance are assessed. The method can be used for optimal design, heat capacity analysis, and life analysis of brakes. [ABSTRACT FROM AUTHOR]

Topology optimization is a well known and sophisticated method for designing structures. Through a finite element analysis, this method optimizes the design and material distribution to obtain an ideal strength-to-weight ratio and improved strain-to-weight ratio. This study involves the development of a comprehensive model for a brake using the ANSYS Parametric Design Language. The purpose of the model is to accurately characterize the geometry of the disc or drum. The technique of a complex eigenvalue analysis is used to identify the presence of unstable modes occurring at distinct frequencies, indicating instability. A braking force of 17,492 kN was exerted at a rotational velocity of 55 rad/s for 10 s. The optimization process resulted in significant mass reduction while maintaining structural integrity. In the drum brake, the mass was reduced from 114.01 kg to 104.07 kg, while the disc brake's mass decreased from 68.81 kg to 56.68 kg. [ABSTRACT FROM AUTHOR]

This study focuses on optimizing double stir casting process parameters to enhance the tensile strength of hybrid composites comprising aluminum alloy, brown pumice, and coal ash, intended for brake disc applications. Analytical techniques including X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy were employed to characterize the composite constituents. The Taguchi method was utilized for experimental design and optimization to determine the optimal weight compositions of brown pumice and coal ash, as well as stir casting parameters (stirrer speed, pouring temperature, and stirring duration). Regression analysis was employed to develop a predictive mathematical model for the tensile strength of the hybrid composites and to assess the significance of process parameters. The optimized composite achieved a predicted tensile strength of 186.81 MPa and an experimental strength of 190.67 MPa using 7.5 vol% brown pumice, 2.5 vol% coal ash, a pouring temperature of 700 °C, stirrer speed of 500 rpm, and stirring duration of 10 min. This represents a 52.23% improvement over the as-cast aluminum alloy's tensile strength. Characterization results revealed that brown pumice and coal ash contain robust minerals (SiO2, Fe2O3, Al2O3) suitable for reinforcing metal matrices like aluminum, titanium, and magnesium. Thermogravimetric and differential thermal analyses demonstrated thermal stability up to 614.01 °C for the optimized composite, making it suitable for brake disc applications. [ABSTRACT FROM AUTHOR]

The article analyses the results of an experimental study devoted to the impact of the mutual overlap coefficient on the friction factor of the model brake lining and brake disk in a disk brake.The mass ratio of the brake lining and brake disc models is 1:200 (the brake lining mass is 8 grams and the brake disk mass is 1,600 grams). The load level has been 0.2–0.5 N. This mass ratio and load level ensure an effective heat removal from the friction zone. The brake disk model is made of 35GS steel. The brake linings are made of two friction materials, i.e. CSiC and SCh25 cast iron. The mutual overlap coefficients for the experiments have been 0.25, 0.5, 0.75, and 1.0. It has been shown that when the mutual overlap coefficient rises from 0.25 to 1.0, there is a tendency for the friction factor to increase in the ‘SCh25 cast iron – 35GS steel’ and ‘CSiC- 35GS steel’ friction units. An increase in the friction factor by approximately 10–12% is observed for the ‘SCh25 cast iron – 35GS steel’ friction pair. An increase in the friction factor is 8–10% for the ‘CSiC- 35GS steel’ friction pair.With effective heat dissipation, the increase in the coefficient of friction occurs due to the reduction in mechanical pressures in the contact area and the increase in the number of micro-irregularities involved in the friction process. [ABSTRACT FROM AUTHOR]

The wheel set of a rail vehicle with a disc brake is the basic assembly of a rail vehicle exposed to abrasive wear. From the operational point of view, the wear process of the wheels and brake discs is uneven, which for the carrier involves switching off the vehicle, once when the maximum wear of the discs is reached and again when the wheels wear out. The process of both untying the wheel set from the bogie, dismantling the wheels and discs from the axle is a time-consuming and expensive process, which consequently affects the exclusion of the vehicle from planned traffic. In the article on the basis of brake disc wear results, 3 concepts of bogie management were proposed. The first concerns the bogie rotation, the second and third concepts concern the exchange of bogies with and without rotation. Using the MUZ multi-criteria programming method, the concepts were evaluated and the best one was selected taking into account the evaluation criteria. The aim of the article is to present concepts that reduce the wear of discs brake systems in a multi-unit traction unit using bogie migration under the vehicle. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology is the property of Automobile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The tribological performance of C/C–SiC paired semi-metallic brake pads suitable for automobiles was investigated in this study. Factors on tribological properties of semi-metallic brake pads such as the contents of phenolic resin, copper fibers, steel fibers and MoS 2 were tested by the orthogonal experimental. According to the SAE-J2522 test procedure, an optimized compositional formulation was derived based on the brake test results combined with fuzzy comprehensive evaluation. The wear mechanism of brake pairs was discussed, and the compositional formulation of the brake pad was further optimized after the analysis of the friction surface morphology before and after braking. The results showed that copper fibers had the greatest effect on the friction performance of brake pads. Copper fibers contributed to stabilization of the coefficient of friction (COF) and effectively improved the wear resistance. However, at higher braking speeds (≥120 km/h), the copper fibers were converted from fibrous to flaky and softened, acting as a solid lubricant on the friction surface, resulting in a low COF of brake pads. The tribological performance of brake pads could be improved by reducing the content of copper fiber and increasing the content of hard particles. [ABSTRACT FROM AUTHOR]

The paper deals with the evaluation of service brake braking of a selected group of vehicles depending on the wear of brake system's parts. During the research, the technical condition of brake systems, the degree of wear of brake discs, brake pads, and the measurement of braking forces using a roller brake tester was monitored and evaluated on a sample of 16 intercity buses for a period of three years. The measurement was carried out on 2 selected intercity buses SOR C 10.5 and IVECO Crossway. The maximum braking forces on both axles of buses were measured using a roller brake tester. Then, the percentage braking of the vehicle was calculated and compared with the minimum required braking according to applicable legislation. Based on the inspection of technical condition of brake pads and discs, it was possible to detect the wear and tear of these elements of the brake system (which was manifested during the inspection of the vehicle on the roller brake tester), and it was also possible to record the insufficient value of the required minimum braking during the calculation. [ABSTRACT FROM AUTHOR]

A new electromagnetic friction braking system was designed in an attempt to improve vehicle braking safety. Structure of the traditional braking system was optimized, and the auxiliary control algorithm of the brake was added to the Electronic Control Unit (ECU), and the working principle of the new braking system under different working conditions was analyzed, the relationship between braking torque at different speeds, the eddy current of the brake disc and the vehicle speed and the applied magnetic field was derived, and the vehicle dynamics model, electromagnetic brake model and vehicle power supply model were established. The joint simulation was carried out based on the Simulink and Maxwell platforms. The results show that on the basis of the traditional braking system, the braking distance can be significantly shortened and the braking performance can be improved by optimizing the electromagnetic brake. And the energy recovery device has successfully realized the recovery and reuse of the vehicle's kinetic energy. [ABSTRACT FROM AUTHOR]

We studied a gradient anti-oxidation coating of C/C composite materials for aircraft brake discs with a simple process and low costs. The gradient coating consists of two layers, of which the inner layer is prepared with tetraethyl orthosilicate (Si (OC2H5)4), C2H5OH, H3PO4 and B4C, and the outer layer is prepared with Na2B4O7.10H2O, B2O3, and SiO2 powder. The experimental results show that after being oxidized at 700 °C for 15 h, the oxidation weight loss of the sample with the coating was only −0.17%. At the same time, after 50 thermal cycles in air at 900 °C, the sample's oxidation weight loss was only −0.06%. We conducted the 1:1 dynamic simulation test for aircraft brake discs, and the brake disc did not oxidize, thus meeting the requirements for aircraft use. In addition, the anti-oxidation mechanism of the coating was analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), differential thermal analysis (DSC-TGA), and high-temperature in situ SEM. [ABSTRACT FROM AUTHOR]

For any type of existing vehicle, one of the most important systems in its structure is the braking system. It is also the main safety element, which stops the vehicle by converting kinetic energy into heat. For constructive reasons and thermal efficiency, ventilated discs are the most widespread and used in industry, therefore, they will also be used in this scientific paper. Ventilated discs are often used to automobile application because of their higher heat dissipation. The purpose of this work is to create a thermally efficient design for ventilated brake discs by adopting two different designs from a constructive point of view. A special importance was also for the brake disc material, initially a semi-metallic material was chosen, being the most used for discs, later the ceramic material was also chosen, which has improved thermal properties. The design variant for the brake disc, to which the disc material and the thermal shield are added, lead to a significant improvement from a thermal point of view, which was also the main objective of this work. Ultimately, this study underscores the pivotal role of innovative design strategies and material selection in advancing the thermal efficiency of ventilated brake discs, thus contributing to the broader landscape of automotive safety and performance engineering. [ABSTRACT FROM AUTHOR]

The increase in payload capacity of trucks has heightened the demand for cost-effective yet high performance brake discs. In this work, the thermal fatigue and wear of compacted graphite iron brake discs were investigated, aiming to provide an experimental foundation for achieving a balance between their thermal and mechanical properties. Compacted graphite iron brake discs with different tensile strengths, macrohardnesses, specific heat capacities and thermal diffusion coefficients were produced by changing the proportion and strength of ferrite. The peak temperature, pressure load and friction coefficient of compacted graphite iron brake discs were analyzed through inertia friction tests. The morphology of thermal cracks and 3D profiles of the worn surfaces were also discussed. It is found that the thermal fatigue of compacted graphite iron discs is determined by their thermal properties. A compacted graphite iron with the highest specific heat capacity and thermal diffusion coefficient exhibits optimal thermal fatigue resistance. Oxidization of the matrix at low temperatures significantly weakens the function of alloy strengthening in hindering the propagation of thermal cracks. Despite the reduced hardness, increasing the ferrite proportion can mitigate wear loss resulting from low disc temperatures and the absence of abrasive wear. [ABSTRACT FROM AUTHOR]

The brake pads of high-speed trains operate under complex and variable conditions, and the collected brake signals are easily affected by noise, making monitoring the health status of brake pads more difficult. A multi-representation adaptation network for online monitoring the health status of high-speed train brake pads, which are affected by noise under variable working conditions, is proposed in this study. First, a parameter-sharing deep residual network is used to extract the friction block features of the source and target domain data. Then, the features are mapped to different low-dimensional feature spaces through the inception adaptation module, and multiple representations are obtained. The network applies conditional maximum mean discrepancy to align representations of the source and target domains, thus learning multiple domain-invariant representations. Hence, the network acquires more knowledge of the friction block status and attenuates the interference of noise signals on the status monitoring. The friction block vibration data were collected from various brake disc speeds, and variable working condition-transfer experiments under the influence of noise were performed on the brake friction and bearing datasets. The results show that the proposed network outperforms other transfer methods, which can better extract and identify the status features of the friction block under the noise interference. [ABSTRACT FROM AUTHOR]

Ni-based VC and TiVC 2 composite coatings were prepared on the surface of worn brake discs by laser direct deposition, and the influence mechanism of trace TiC addition on the microstructure and performance of the coating was investigated. The microstructure of the coatings was analyzed by XRD, SEM, EDS, and TEM, which revealed the evolution mechanism of the microstructure during the laser deposition process. The friction wear performance was tested on friction wear equipment. The results showed that VC 0.88 was formed by the in-situ reaction of C and V under the action of the laser, which presents dendritic morphology. After the addition of TiC particles, TiVC 2 was further synthesized along the TiC particles in addition to dispersed VC 0.88 in the coating. It can be seen that the addition of trace TiC particles inhibited the formation of VC 0.88 dendrites and enhanced the plastic toughness of the coating. HRTEM calibration proved the existence of TiVC 2 and Ni, and there was no obvious orientation relationship between the interface. The friction coefficients of Ni-based VC and Ni-based TiVC 2 coatings with Al 2 O 3 balls were 0.59 and 0.51 at room temperature, respectively. After 1.5 h of high-temperature wear at 300 °C and 600 °C, the distribution of wear marks shows a groove and high-temperature fatigue appearance. The TiC-doped coating has better wear properties than the base material and the original coating is expected to meet the requirements for brake discs. [ABSTRACT FROM AUTHOR]

The study of the tribological behavior of the braking system in auto vehicles requires knowing the characteristics of the material in contact and, in the work process, the friction pair brake disc pads. Material structural analysis is necessary because the wear process depends both on the friction-pair chemical composition (brake disc pads) and on the work process parameters (pressing force, rotational speed, traffic conditions, etc.). The material of the brake discs is generally the same, gray cast iron, and the brake pads can be semimetallic (particles of steel, copper, brass, and graphite, all united with a special resin), organic materials (particles of rubber, glass, and Kevlar, all joined with the help of a resin), composite materials that contain different constituents, and ceramic materials (rarely have small copper particles). Therefore, the purpose of this paper is to analyze the crystalline structure, tribological behavior (at friction and wear), and the mechanical properties of the materials of the brake disc–pad friction pair specific to the field through study and analysis. [ABSTRACT FROM AUTHOR]

This study established a novel vehicle–track coupled dynamics model (VTCDM) considering the disc brake system of a high-speed train (HST). The structure parameters of each friction block are applied to compute the non-linear friction forces and torques. This more elaborate model enables detailed investigations on the coupled mechanical system excited by the brake sliding friction, wheel-rail rolling friction and track irregularity. Further, it is validated by comparing with the experimental results from the aspects of time domain, frequency domain, Poincaré map and phase plane. Results indicate that the brake system substantially influences the vehicle–track system (VTS) and causes strong non-linear characteristics. Furthermore, this model can be used for tribological and dynamics-related assessment, like braking squeal and friction-induced vibration. [ABSTRACT FROM AUTHOR]

Firstly, the Canny operator combined with circle fitting is used to position the working surface. Secondly, the median filter and the Laplacian operator are selected for preprocessing. Due to uneven illumination, surface texture, or environmental dust, the extracted scratches exhibit fragmentation, and traditional morphological operations cannot handle scratches well, so an improved Canny operator combined with probabilistic Hough transform is proposed for scratch connection. A bidirectional connection is introduced to optimize the edge detection process of the Canny operator, and a parallel algorithm is introduced to shorten the detection time. Finally, the standard Hough transform needs to traverse the entire parameter space, and the calculation is complicated, and the probability Hough transform is selected. The experimental results show that compared with the traditional Canny algorithm, the precision, recall, and F1‐score of the improved Canny algorithm are increased by 3.2%, 13.2%, and 6.0%, respectively. After adding parallel processing, the average detection time was reduced by 45 ms. Finally, the accuracy of scratches extracted using this algorithm reached 97.96%, the leak rate, and mistake rate of this study are only 3.33% and 2.00%, which provides a more accurate and efficient theoretical support for the research on brake disc scratch detection. [ABSTRACT FROM AUTHOR]

The geometry of the disc cutter is one of the most important factors in the rock cutting process of mechanized tunnel boring machines (TBMs). However, during excavation, the optimal conditions of the disc cutter are not constant due to disc cutter wear. One of the most significant consequences of cutter wear is the increase in the contact area of the disc cutter with the rock so when the wear of the cutter exceeds its maximum limits, it should be replaced. Therefore, this study will examine the effect of disc cutter wear on TBM operational parameters such as thrust force, net penetration rate, and specific energy. In order to achieve this, six types of worn 17" disc cutters have been studied graphically, and a method for calculating the surface of contact between the disc cutter and rock as a function of the cutter tip width has been developed. Moreover, a new equation has been proposed to predict normal and rolling cutting forces whose results are in good agreement with the reported laboratory values. As a final step, the hard rock TBM parameters of the Kani Sib water conveyance tunnel have been studied after replacement of worn disc cutters. The results show that replacing the worn disc cutters leads to an increase in penetration rate and a decrease in thrust force, resulting in an increase in specific penetration. On average, specific penetration increases by ≈35 %. [ABSTRACT FROM AUTHOR]

The proper representation of friction contact conditions between each wheel and the rail is necessary to accurately model the behaviour of a heavy haul locomotive since friction conditions at the wheel-rail interface affect the locomotive's dynamic performance under traction and braking conditions. In normal operations, a phenomenon commonly known as rail cleaning effect occurs. The rail cleaning effect causes increased friction coefficients between the following wheel treads and the rail head. The wheel-rail interaction causes the third body layer to be partly or wholly eliminated from the surfaces in contact and generates new layer. An experimental analysis of the changes in friction coefficients under simulated locomotive wheel-rail contact conditions, in terms of contact pressure and slip, is presented in this paper. For this study, data processing equations are presented to obtain the experimental traction coefficient and slip. Furthermore, the rail cleaning effect is examined under different slip conditions. The experiment shows the traction coefficient increases for a given number of cycles until reaching a steady value, demonstrating that the rail cleaning effect is measurable in various slip conditions on a twin disc machine. [ABSTRACT FROM AUTHOR]

The full-carbon/ceramic brake pair is designed to meet the increased demands for reliable braking at high speeds, heavy loads and complex service environments for vehicle and power machinery. In this paper, braking performance of different Fe–Si modified C/C–SiC composites have been studied using laboratory scale dynamometer. The phase composition/microstructure and mechanical properties of the material were studied. By mating with C/C–SiC brake disc, the effect of Fe–Si alloy modification on the friction and wear performance of full carbon/ceramic brake pair was investigated. The results indicated that the Fe–Si modification can effectively improve the wear resistance of both C/C–SiC disc and pads, and the disc/pads will have the least amount of wear only when the appropriate type of Fe–Si alloy and the suitable amount of Fe–Si alloy phase are introduced. When FeSi75 was used as the fusion infiltration material, the wear of disc/pad was 115.4 and 13.3 mm, respectively. Compared to the unmodified C/C–SiC disc/pad, the wear of Fe–Si modification disc/pad was reduced by 72.7 % and 87.2 %, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Ingeniería Mecánica is the property of Editorial UNED and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)