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Purpose. To study the course of heat phenomena in disc brakes using modern computing systems in order to determine and substantiate the operating parameters for the hoisting machine components. Methodology. The research uses software packages, with the help of which a computational-theoretical apparatus is developed for heat mode modeling processes. In particular, the mentioned function is used in the SolidWorks Simulation software with the ability to evaluate the errors of the calculation results. Findings. In the course of the research, the dependence of the hoisting machine disc brake performance on the operating parameters of its components was determined. The research has led to a better understanding of the heat transfer processes in disc braking devices, as well as the ability to study the friction response of various materials and determine optimal parameters that help improve the performance of braking systems. The effectiveness has been proven of the proposed method for analyzing the heat distribution processes of the mine hoisting machine drum components under the influence of operating and emergency braking modes. Originality. For the first time, a methodology for calculating the heating temperature distribution along the brake rim plane during a safety stop has been developed and substantiated. A method has also been developed for determining the temperature field arising under steady-state heating conditions, which occur after repeated operating braking and cooling of the device. In this case, when using the formula for determining the temperature on the brake rim surface, the sample length, the relative velocity between the friction components and the heat flow distribution coefficient are taken into account. The brake disc geometric model developed in the SolidWorks software package makes it possible to study the temperature change on the device rim in real time. Practical value. The proposed design improvement based on the research results of heating processes should improve vehicle safety. The cost of braking systems is expected to be reduced through the use of optimal materials and production technologies. The software methods for modeling and analyzing the temperature influence on brake discs of the Mine Hoisting Machine (MHM) have been improved. Based on the research results, recommendations have been developed for the optimum braking process of machines in various operating conditions. [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]

In this paper, vibration and stability analysis of a rotating Functionally Graded Material (FGM) disc brake considering the hot band phenomena are studied. In order to model the hot band phenomena, the disc brake is divided into two sections, the inner disc and the outer ring. The latter is where thermal and mechanical loads are applied. Based on Hamilton's total potential energy principle and applying first-order shear deformation theory (FSDT), the governing equations are derived. Furthermore, the derived equations of motion are solved via the Generalized Differential Quadrature (GDQ) method. The results reveal that using a functionally graded material would improve the mechanical and thermal characteristics of a disc brake, most notably higher buckling temperature and smaller deflection in a disc brake. Moreover, using a functionally graded material for a disc brake will result in increasing the natural frequency of the disc, that is to say, the buckling will occur at higher rotational speeds. Following this further, the effects of the radius of loading annular ring, where thermal and mechanical loads are applied, as well as gradation index and mechanical and thermal loading, are also studied. The results show there is a non-linear relation between the radius of the loading annular ring and deflection as well as critical buckling temperature. Furthermore, a comparison of results with those available in the literature shows good agreement. [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]

AbstractThe brake disk and friction material parameters were taken as design variables, with the negative damping ratio of the unstable mode as the optimization target. The central composite design method was employed to obtain suitable data sample points. A neural network response surface model was constructed to predict the real part values of the unstable mode. Structural optimization design was then conducted using a screening method to derive optimized parameters for the brake disk structure and physical parameters such as density, elastic modulus, and Poisson’s ratio of the friction material. The optimized coefficient of the negative damping ratio of the brake system’s unstable mode was enhanced, thereby reducing the likelihood of brake squeal. Harmonic response analysis showed a significant optimization effect on the curve of brake disk amplitude fluctuations with frequency. These findings offer valuable insights for improving the stability of disk brake systems. [ABSTRACT FROM AUTHOR]

Failure of the brake system causes many fatalities that lead to accidents; one of the many causes is Brake Fade. Brake fade mostly caused by braking temperature that exceeds the maximum temperature of the brake lining material, resulting in a decrease in the coefficient of friction (braking power). Therefore, this paper was conducted to analyze the effect of braking temperature on the coefficient of friction, thickness reduction, and braking time. The type of brake used is a disc brake with four brands of brake lining including, AHM brand, Indopart brand, OSK brand. The test method carried out in this research is divided into two methods, the first method is braking from a variety of RPM until a steady condition (the state of the engine stops), and the second method is performing braking cycle test where braking is carried out every 500 RPM with a holding time of 1 minute. Measurement of braking temperature using an Infra-red thermometer and thermocouple which becomes a series of RMS-Brake. Measurement of braking time and brake lining thickness before and after the test is also carried out to determine its effect on braking temperature. As the test results, AHM brand fading at a temperature of 305.9°C with a friction coefficient of 0.09738, Indopart brand fading at a temperature of 191.1°C with a friction coefficient of 0.1067, OSK brand fading at a temperature of 203.7°C with a friction coefficient of 0.109057. In addition, there is also the effect of temperature on the reduction of brake lining thickness, where the AHM brand is the least thickness reduction of 0.1 mm to reach 250.4°C. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING 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.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING 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.)

Exploring Noise Reduction in Automotive Disc Brake Systems: Investigating the Impact of Viscoelastic Core Sandwich Plates. This study delves into the phenomenon of brake squeal noise generated by automotive disc brake systems. It focuses on analyzing the response of sandwich plates with viscoelastic cores, which are employed within brake systems to mitigate squeal noise arising from friction between brake pads and the brake disk. Through a series of finite element analyses conducted under varying operational conditions, including friction coefficient and angular velocity, the research aims to ascertain the complex eigenvalue of the disc brake system in order to identify unstable modes. The findings underscore that the incorporation of viscoelastic layers within preloaded, slender sandwich plates introduces nonlinear dynamic characteristics that contribute to the reduction of squeal noise within braking systems. [ABSTRACT FROM AUTHOR]

Railroad vehicles require the use of disc brakes for safety purposes, however, the brakes are susceptible to thermal stress, which ultimately shortens their lifespan. Hence, to accurately predict the life of railway disc brakes in thermal load simulations, the availability of a model that considers spatial and temporal variations of temperature and thermal stress is essential. A non-axisymmetric moving heat source model was successfully developed to address spatial temperature variations (Deressa and Ambie in Urban Rail Transit 8(3–4):198–216, 2022. 10.1007/s40864-022-00176-9), and this study aims to extend this model to predict thermal stress and fatigue life, and assess its effectiveness. The analysis includes braking time thermal analysis, cooling time thermal analysis, and structural analysis. Spatially varying temperature is incorporated into the structural analysis to calculate thermal stress and strain. A fracture mechanics-based fatigue life estimation method is applied to critical areas of the friction surface. The model is implemented on two braking conditions (service and emergency) and two disc geometries (actual and modified). The model successfully resolves spatial heat considerations by estimating maximum stress variations of up to 46 MPa along the disc circumference. Stress differences of 3 MPa and 6 MPa are observed between the leading and trailing edges of the pad trace during late and mid-braking times, respectively. Fatigue life results identify critical positions and directions for fatigue life initiation. Additionally, these results are in accord with previous observations available in the literature. The proposed model can be easily implemented in various sliding friction applications such as drum brakes, engine pistons/cylinders, and camshafts. [ABSTRACT FROM AUTHOR]

Abstract Railroad vehicles require the use of disc brakes for safety purposes, however, the brakes are susceptible to thermal stress, which ultimately shortens their lifespan. Hence, to accurately predict the life of railway disc brakes in thermal load simulations, the availability of a model that considers spatial and temporal variations of temperature and thermal stress is essential. A non-axisymmetric moving heat source model was successfully developed to address spatial temperature variations (Deressa and Ambie in Urban Rail Transit 8(3–4):198–216, 2022. 10.1007/s40864-022-00176-9), and this study aims to extend this model to predict thermal stress and fatigue life, and assess its effectiveness. The analysis includes braking time thermal analysis, cooling time thermal analysis, and structural analysis. Spatially varying temperature is incorporated into the structural analysis to calculate thermal stress and strain. A fracture mechanics-based fatigue life estimation method is applied to critical areas of the friction surface. The model is implemented on two braking conditions (service and emergency) and two disc geometries (actual and modified). The model successfully resolves spatial heat considerations by estimating maximum stress variations of up to 46 MPa along the disc circumference. Stress differences of 3 MPa and 6 MPa are observed between the leading and trailing edges of the pad trace during late and mid-braking times, respectively. Fatigue life results identify critical positions and directions for fatigue life initiation. Additionally, these results are in accord with previous observations available in the literature. The proposed model can be easily implemented in various sliding friction applications such as drum brakes, engine pistons/cylinders, and camshafts.

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering 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 article presents the results of thermovision tests of the disc brake and the drive system components located in its vicinity on the 111Ed electric locomotive in field conditions. For this locomotive, tests were carried out on a test track to measure the temperature of the disc and the temperature of other devices that were installed close to the brake disc. These tests were performed pointwise, i.e. before and after the test, and continuously throughout the braking process. The article presents the methodology of thermal imaging research and the preparation of the camera for outdoor research with objects with different emissivity. Due to the rotating brake disc, it was decided to measure using an IR camera because measurements using thermocouples were very difficult and complex. In exceptional situations, temperature measurement using thermocouples is used, but it requires an extensive additional measurement system and signal recording, which is more expensive. Correct configuration of the IR camera to real conditions is extremely important because it directly translates into the increase in measurement error. [ABSTRACT FROM AUTHOR]

Brakes are used to stop movement or adjust speed to ensure safety for mechanisms or machines. In this paper, the brake applied to hand winch will be studied. This hand winch has been studied by us in previous stages. However, the disadvantage of the winch is that the drum wall attached to the friction surfaces is not reasonable in terms of layout, as well as the parameters to optimize braking moment have not been calculated. A new brake structure is proposed in this study to solve the above problem. This structure does not use the drum wall as the friction surface. It does not affect the drum wall and it is easy to replace the friction surface when necessary. Instead, the cone brake is suitable for the structure brake and the size, structure, and design load. To determine the optimal parameters of the brake structure, the article will analyze the theory, and experiment design. The objective function is the maximum braking torque. Constraints are hand winch parameters, installation, friction surface material, and loading conditions. The corresponding factors are coded according to the Taguchi method, the orthogonal planning matrix is L18. Using Minitab software to analyze the Signal/Noise ratio, the study determined the optimal values for five factors including screw thread pitch, coefficient of friction (screw thread), cone angle, friction coefficient (brake), and large cone brake radius. Research results have selected the optimal parameters of the brake, and the optimal values have satisfied the constraints. The torque at the cone brake is greater than that of the disc brake approximately 37.7 %. The pressure at the friction surface is reduced by about 55 % compared to the disc brake surface. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING 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.)

As part of ongoing research, a wheelchair dynamometer has been designed and built. This device is a complex test stand, enabling research on the operation of wheelchairs, taking into account a number of biomechanical factors in laboratory conditions. Based on a review of the available literature, the braking system was designed and constructed as a part of a dynamometer drive system. This has resulted in a design issue concerning the optimal selection of the electromechanical drive combined with a hydraulic system as the actuator of the brake. The purpose of the research discussed here is to determine the characteristics of the braking system. For this purpose, a series of tests were carried out using a wheelchair with an electric drive, which allowed the generation of a constant rotational speed in the range between 72 rpm and 222 rpm. Based on the test results, the hysteresis of the developed braking system and the characteristics of the braking power were determined. [ABSTRACT FROM AUTHOR]

Aiming at the lightweight design of the disc brake for small family cars, the finite element analysis and multi-objective optimization of the disc brake were carried out.Through the sensitivity analysis, the contribution degree of each size parameter of the brake disc to the braking performance and quality was established, and the optimization variables were quickly selected.Taking the lightest weight of the brake disc, the lowest surface temperature of the brake disc and the minimum maximum equivalent stress as the objective function, a multi-objective optimization mathematical model was established. NSGA-II hybrid variant algorithm based on the control elite strategy in Ansys was used to optimize the brake disc. After the optimization, the quality of the brake disc is reduced by 29.2% by simulation. The correctness of the simulation results is verified by the experiment under the same working condition, which realizes the lightweight of the brake disc and provides a reference for the design of the disc brake.

Focusing on investigating the brake squeal problem of a disc brake at 3 000 Hz. To this end, the noise of this frequency is reproduced on the bench, the laser Doppler vibration measurement technology is used to obtain the operational deflection shape（ODS） at this frequency. Finite element analysis（FEA） model is established and modified according to the experimental modal. The complex eigenvalue analysis is adopted to retrieve the complex eigenvalues and mode shapes.The correlation analysis is used to confirm that the complex eigenvalue results are valid for the actual noise ODS results.Afterwards, analysis of the components contribution and the components modal contribution of this unstable mode are used to provide corresponding structural optimization plan, and a bench test has been carried out to verify the effectiveness of this method.

Manny disc brake are produced at conventional machinery workshop. But, the optimum value of disc brake based on heat dissipation, and the safety is unknown. One of the causes of vehicle accidents is the vehicle factor (brake failure). Prolonged and continuous braking on the disc brake can result in fadding. Continuous stress generation can decrease fatigue life. The required material and the right number of holes are needed to solve this problem. The Purpose of this research is to get the optimum temperature and stress value. In this study, simulations were carried out with CAE software on disc brakes with materials Al 7075- T6, SS 304, gray cast iron and the number of ventilation holes 36, 48, 60. The results show that the disc brake with Al 7075-T6 material and 60 ventilaton holes has the best heat dissipation with 38,005ᴼC temperature value. Material gray cast iron with number of ventilation holes 48 produces the lower equivalent stress with 89,272 Mpa. From the research it can be concluded, disc brake with higher density,has higher temperature too. The greater tensile strength of disc brake material, resulting the lower equivalent stress. The gray cast iron material and the number of ventilation holes 48 is the most optimal in temperature absorption, the longest fatigue life, and the highest fatigue safety factor, with a temperature value of 54.99ᴼC, a fatigue life of 100000000 cycles, and an FOS of 3.34.The more number of ventilation holes, has the lower of temperature result but the higher stress concentration.

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering 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.)

Brakes are used to slow down or stop a moving object. The temperature of the disc brake will rise as a result of the conversion of kinetic energy from vehicle speed into thermal energy during the braking operation. To prevent harm to the disc brake or other components, the heat generated by this disc brake must then be released into the environment. Therefore, it is crucial to provide effective heat dissipation to the environment. Increasing the surface area where heat is dissipated into the environment is one potential solution. In this study, the variation of the drill hole angles and groove hole angles is proposed as a geometry modification to encourage greater heat dissipation in disc brakes. In addition, the thermal performance of disc brakes made from various types of materials is assessed using finite element analysis. The materials employed are carbon ceramic, stainless steel, and gray cast iron. The numerical findings show that the groove-type disc brake with a ventilation hole angle of 0° angle has the lowest maximum temperature. In addition, it is revealed that the disc brake made of gray cast iron material results in the lowest peak temperature. The numerical results also indicate that due to the thinning of the geometry, the addition of the ventilation hole angle contributes to the phenomena of temperature concentration in specific areas of the disc brake. This study demonstrates that disc brake material and ventilation hole play a significant effect in altering the thermal characteristics.

The article suggests a disc brake design with carbon friction materials (CFMs). The principle of the method is to create two friction units in the disc brake with materials placed in them that have different frictional properties. The two friction units are created by separating the brake disc with a thermally insulating screen. One friction unit (friction unit A) has CFMs installed having a low friction coefficient in the initial temperature mode and a high friction coefficient at a temperature of 300°C or higher. The other friction unit has a premium-class car block (CB) and a steel disk (35GS steel) the friction coefficient of which does not depend on temperature (friction unit B). The experiment conducted justifies the creation of a disc brake based on the described principle. The experiment was carried out on a testing bench that simulates the interaction of the disc brake as per the load-speed criteria. The testing bench creates conditions for a constructive separation of the brake disc into friction units A and B. As an example of two friction units: CFM–CFM (friction unit A) and CB–steel 35GS (friction unit B). The experimental performance of the friction coefficient versus temperature obtained on the testing bench in relation to friction units containing friction materials CFM–CFM and CB–steel 35GS showed that the friction coefficient of the disc brake takes high values in the entire range of temperatures tested during braking. The article offers a promising design of a disc brake with thermally insulated friction units. The design consists of two brake discs and a central part, which is thermally insulating. All parts are glued together. [ABSTRACT FROM AUTHOR]

The brake system is the most significant active safety system that converts the vehicle's mechanical energy into heat energy based on the braking pair's friction. The transfer of heat in the brake pair during braking occurs by conduction, convection, and radiation. In disc brakes, which are widely used today, the effect of the heat transfer coefficient, which continually changes with the disc's angular velocity on the cooling of the braking pairs is important. The change in heat convection coefficient can be calculated with a numerical approach. In this study, on disc temperature effect of heat convection coefficient and angular velocity has been examined with the finite element method using the experimental data in the SAE J2522 Comprehensive Brake Efficiency Test Standard, fading test procedure. Disc brake design has been designed in the SOLIDWORKS program, and analysis has been carried out using ANSYS 2020 R2 in steady-state thermal analysis. It has been determined that the cooling amounts at the initial of braking are higher than the cooling amounts at the end of braking, and the effect of cooling by convection in the reduction of the temperature difference at the end of braking compared to the initial state is between 91.22% and 91.74%. [ABSTRACT FROM AUTHOR]

Railway disc brake is vulnerable to surface damages including fade, wear, squeal, thermal cracks and fatigue being just few of them. To counteract these negative consequences, reliable thermal model that can accommodate space and time variables is essential. The aim of this study is to develop new non-axisymmetric moving heat source and compare its efficiency with pre-existing traditional models. Factors responsible for temperature spatial and temporal variation are identified first and then programmed in ANSYS APDL similar capability to a FORTRAN. Heat flux and convection coefficients are calculated by empirical equations and stored in parameters and arrays for later use, based on small time and pad angular increment. The modelling is to successfully solve the problems in traditional models by estimating surface temperature difference as high as 49 °C, within acceptable computation time. Besides, its consideration of radial distance reported variations from traditional models as high as 10% and 60% in moving heat source and axisymmetric, respectively. And, it is also verified with the literature within acceptable variation. Finally, it is suggested that the model can be applied in conducting pad geometry optimization, thermal stress and fatigue life of disc brake. [ABSTRACT FROM AUTHOR]

Drag torque in a disc brake is the residual torque when the brake is not activated. This torque can adversely influence the total energy consumption, life of the brake components, and level of airborne wear particles from vehicles. Drag torque is of special interest for long haul trucking since it could have an effect of the total energy consumption. Drag torque performance of a disc brake is usually evaluated with conventional inertia dynamometers. Vibrations induced by the wheel can help to retract the pads from the disc and decrease the drag torque. It is hard to study this phenomenon with conventional inertia dynamometers since there is usually no system to induce a forced vibration on the brake. Therefore, the aim of the paper is to investigate the effect of vibrations on the drag torque for a commercial vehicle disc brake with a novel test setup. This is done by comparing test run with and without pads, forced vibrations, and pad retraction springs. The results indicate that the forced vibrations strongly affect the level of measured drag torque. In addition, the introduction of a retraction spring can reduce drag torque with more than 50% when vibrations are induced.

At present, experimental research on the friction hot spots phenomenon of disc brake generally focuses on phenomenon analysis, without in-depth analysis of the relationship between the occurrence of hot spots, temperature, and deformation, result in unclear generation mechanism of friction hot spots. Therefore, this article first conducted a brake hot spot bench test, reproducing the phenomenon of brake hot spots at different speeds and brake pressures. A large amount of temperature and deformation field information during the formation process of brake hot spots was collected using infrared thermal camera, displacement sensors, vibration acceleration sensors, etc. Secondly, detailed data processing was carried out on the temperature and deformation fields, a three-dimensional spatial map of angle-radius-temperature was formed by unfolding the temperature field information collected by the infrared thermal camera along the circumferential direction, and the DTV, LRO, and ACZ information collected by displacement sensors and vibration acceleration sensors were innovatively convert from temporal domain into angular spatial domain, and the spatial domain information were then transformed into spatial frequency domain through the designed spatial Fourier transform. In addition, larger initial morphology signals were filtered out through wavelet decomposition. The above innovative data processing methods convert both the temperature and deformation time domain information during the hot spots generation into the spatial domain, so the interaction relationship between them and the hot spots can intuitively be analyzed. Based on this, this article finally analyzes the hot spots generation mechanism and draws the following key conclusions: (1) The generation of hot spots has critical speed and critical pressure; (2) The hot spots are alternately distributed on both sides of the brake disc, with a phase difference of 180°; (3) During the braking process, the deformation field changes before the temperature field, and the temperature field and the final number of hot spots depend on the stable deformation field; (4) During the evolution process of the deformation field, LRO and DTV mutually stimulate each other and alternately evolve towards higher order; (5) The main order and amplitude of the stable waveform of LRO (waviness distortion) are the decisive factors in the final number of hot spots. [ABSTRACT FROM AUTHOR]

In recent years, the use of unmanned aerial vehicles (UAVs) has increased significantly. Asymmetrical factors, or frictional studies on the disc brake of UAVs, are one of the safety considerations taken into consideration during the design process because UAVs and their components have been built with the best safety in mind. This study focuses on choosing the optimal material for a UAV's disc brake by using transient structural and thermal models. In order to compare the asymmetry-based frictional force produced by the two ways; the processes used in the transient simulation are validated using pin-on-disc (POD) testing. The foundation for this validation investigation is a metal matrix composite made of an aluminum alloy, and the basis tool is an ASTM G99-based computational test specimen. Steel-EN24 and carbon ceramic matrix composites testing are expanded using the same POD tests. A range of 3 percent to 8 percent error rates is found. As a result, the calculation techniques are applied to the UAV's disc brake after they have proven to be trustworthy. This fixed-wing UAV's extensions have a 5 kg payload capacity. The weight, avionics components, tire dimensions, and disc brake dimensions of the other UAV design parts are calculated using analytical formulas. The final designs are made using CATIA as a result. The grid convergence experiment is organized using a traditional finite element analysis tool. Finally, at its maximum rotational speed, a UAV's disc brake is put through asymmetrical friction testing based on structural and thermal consequences. The correct materials for critical applications, such as carbon fiber-woven-wet-based reinforced polymer and Kevlar unidirectional-49-based reinforced polymer composites for changing rotating speeds, have now been made possible by fixed-wing UAVs. [ABSTRACT FROM AUTHOR]

Analysis of mechanical and thermal behaviors during braking has become an increasingly important issue in many transport sectors for different modes of transportation. Brake failure generated during braking is a complex phenomenon confronting automobile manufacturers and designers. During braking, kinetic energy is transferred to thermal energy, resulting in the intense heating of disc brake rotors that increases proportionally with vehicle speed, mass, and braking frequency. It is essential to look into and improve strategies to make versatile, thermally resistant, lightweight, high-performance discs. As a result, this study uses the finite element method to conduct a thermo-mechanical analysis of aluminum alloy and aluminum matrix nano-composite disc brake rotors to address the abovementioned issues. The FEA method is used for the thermo-mechanical analysis of AMNCs for vented disc brake rotor during emergency braking at 70 km/h. From the results obtained, aluminum base metal matrix nano-composites have an excellent strength-to-weight ratio when used as disc brake rotor materials, significantly improving the discs' thermal and mechanical performance. From the result of transient thermal analysis, the maximum value of heat flux obtained for aluminum alloy disc is about 8 W/mm2, whereas for AMNCs, the value is increased to 16.28 W/mm2. The result from static analysis shows that the maximum deformation observed is 0.19 mm for aluminum alloy disc and 0.05 mm for AMNCs disc. In addition, the maximum von Mises stress value of AMNC disc is about 184 MPa. The maximum von Mises stress value of aluminum alloy disc is about 180 MPa. Therefore, according to the results, the proposed aluminum base metal matrix nano-composites are valid for replacing existing materials for disc brake rotor applications. [ABSTRACT FROM AUTHOR]

Purpose. A simplified calculation method development for strengthened split cylindrical drum structures of the mine hoisting machines of the TsR-6.75×6.2/1.95 type. Methodology. The drum structure for the mine hoisting machines is conventionally divided into several nodes. A simplified averaged model is constructed for the nodes consisting of the shell, frontal, rib strengthening and brake discs (end nodes) based on the analysis of their operation, in particular, the stiff ness analysis under different loads. After that, when assembling, the initial drum nodes are replaced with simplified ones and a so-called “simplified” model for the whole drum is constructed, as well as the displacements of the brake disc edges are determined. Findings. The simplified models for drum nodes have been created based on the analysis of their operation, and then the displacements of the whole drum simplified model have been calculated. Originality. The simplified calculation method error has been estimated: the method of averaging with increased thickness of the frontals. Practical value. For the TsR-6.75×6.2/1.95 hoisting machine with a drum diameter of 6750 mm, a drum width of 6200 mm and an adjustable part width of 1950 mm, with a groove cutting pitch of 51 mm and a maximum lifting depth of 1477 m, it has been determined that the maximum axial displacements for brake disc edges of the jammed and adjustable parts are 0.854 and 1.921 mm, respectively. A simplified calculation method has been developed for strengthened split cylindrical drum structures of the mine hoisting machines of the TsR-6.75×6.2/1.95 type, available for use in middle-class packages such as SolidWorks Simulation. [ABSTRACT FROM AUTHOR]

One of the causes of traffic accidents is the vehicle factor caused by the brake system that is not functioning properly. Brakes are a very important component in a vehicle, its function is to reduce the kinetic energy of the vehicle where the safety of the driver is very dependent on this component. Materials are very important role in the design of disc brakes, the main factor in the braking process is friction, and each material has its own friction coefficient. In the automotive industry there are many types of disc brake materials, so it is necessary to conduct a more indepth study on the effect of the disc brake material to determine the deformation, stress and strain that happen during the braking process. The method we used is to design a disc brake on solidworks and simulate it in ansys 19.2 software to find the structural transient values of gray cast iron, aluminum alloy, stainless steel, and titanium alloy materials. The result of this research is a data on the transient structural disc brake of the Vario 125 CBS motorcycle with the highest maximum total deformation happens in the gray cast iron material of 8.4965 mm. For the maximum value of equivalent elastic strain, the highest happens in aluminum alloy material at 0.012275 mm/mm. For the highest maximum equivalent stress value happens in stainless steel material at 1494.3 Mpa.

As part of ongoing research, a wheelchair dynamometer has been designed and built. This device is a complex test stand, enabling research on the operation of wheelchairs, taking into account a number of biomechanical factors in laboratory conditions. Based on a review of the available literature, the braking system was designed and constructed as a part of a dynamometer drive system. This has resulted in a design issue concerning the optimal selection of the electromechanical drive combined with a hydraulic system as the actuator of the brake. The purpose of the research discussed here is to determine the characteristics of the braking system. For this purpose, a series of tests were carried out using a wheelchair with an electric drive, which allowed the generation of a constant rotational speed in the range between 72 rpm and 222 rpm. Based on the test results, the hysteresis of the developed braking system and the characteristics of the braking power were determined.

For material fracture and severe wear in braking conditions, the discrete element method (DEM) is used to simulate the wear process of the braking interface explicitly. Based on the central difference method, particle motion equations are established considering the influence of elemental damping on particle contact. Combined with the Particle Flow Code (PFC) software, a DEM wear model of the braking interface is established using the parallel bond modeling method. The braking wear process is simulated, and the material damage process is investigated. The simulation results demonstrate that with the increase of the initial braking load and the initial braking speed, the wear depth increased by 24.75% and 16.22%, respectively. The increase in the number of detached particles leads to an increasing trend of fracture force chains, which increases the thickness of the flowing particle layer, revealing the micro-wear mechanism of the braking interface. [ABSTRACT FROM AUTHOR]

In the present work, the study of fatigue failure of the disc brake of Volvo truck under thermomechanical effects across the disc thickness is reported. Both analytical and numerical approaches have been used. In the analytical approach, flat rigid asymmetric punch contact behavior was assumed at surface interaction, while in the numerical approach, the 3D finite element model of the vented disc type is subjected to thermomechanical cycles using ABAQUS software. Linear elastic material models were used to simulate the material's behavior under the applied pad pressure on the disc. Surface-to-surface type of contact was used for bodies that have arbitrary shapes with relatively large contact areas at disc pad interfaces. The crack initiated due to hydraulic pressure of 1.47 MPa on the disc was analyzed under mixedmode (mode I and II) conditions. This analysis has shown that the crack propagated up to critical length of 6.02 mm and finally, failure of the disc brake was observed. [ABSTRACT FROM AUTHOR]

This paper introduces the technical transformation and system realization of the hoister gap monitoring and protection device in Hongyang No.2 Coal Mine. Through the high-precision laser displacement sensor, we detected displacement signals, such as brake clearance, brake wear value, spring fatigue and brake disc deflection, to convert into 4-20 mA current signal to transmit to the PLC analog input port. PLC can read, analyze and convert the data in real time, and convert it into numerical value which is easy to display. Sound and light alarm signal is sent when the set value is exceeded. The practical application proves that the device has the technical characteristics of high sensitivity, strong anti-interference ability and reliable operation.

Based on the rheological properties of MRF，a disc-type MR brake with rectangular bump is designed，and the calculation formula of its braking torque is derived. The simulation model is established based on Matlab/Simulink， and the size parameters of rectangular bump are continuously optimized. The simulation results show that when there are 12 rectangular bumps with a width of 2 mm and a depth of 1.5 mm， the braking torque is 626 N·m， which is 31.5% higher than that of the bumps without machining. It shows that the designed MR brake can effectively improve the braking torque.

As an important basis for its structural optimization design, the heat transfer performance has a key influence on the reliability of automobile brake. Based on the finite element method, the transient heat transfer of automobile disc brake is analyzed under the condition of dynamic convection heat transfer coefficient. According to the simulation results, the CCD (Central Composite Design) sampling scheme is used to transform the optimization variable and target variable into multiple design points in the decision space. The optimization variable includes the total thickness, the height of the ventilation slot, the angle between the sides of the ribs, the number of ribs while the target variable includes the mass and temperature peak. According to the multiple quadratic regression model, the response surface function is constructed, and the approximate model of optimization analysis is obtained. The error analysis shows that the response surface function is equipped with good fitting accuracy. In order to facilitate the extremum search, the optimization of the quality is transformed into the constraint condition, and the multi-objective optimization problem of the brake disc is transformed into the single objective optimization problem. Through the sequential quadratic programming method, the Pareto optimal solution set of the optimal mathematical model is found. The results show that the temperature peak value is reduced by 7.8 % under the condition where the quality of the ventilation plate is basically unchanged. By weighting the Pareto optimal solution sets of different quality intervals, a good result evaluation of ventilation panel optimization is achieved. [ABSTRACT FROM AUTHOR]

The study considers the principles of creating a disc brake, promoting consistently high friction in a wide range of brake temperatures. The selection of friction materials for thermally insulated friction units is carried out according to the principle of mutual compensation of the negative properties of one friction unit due to the positive properties of another one. For example, for a cast iron–35GS steel disc brake, when heated to 300°C, the friction coefficient changes from 0.38 to 0.17, while for a carbon–35GS steel disc brake, the reverse effect of a coefficient variation from 0.17 to 0.58 is observed. A combination of the given tribological systems provides an acceptably high friction coefficient in the entire brake temperature range. A disc brake with two heat-insulated friction units makes it possible to improve the rolling stock braking efficiency. The cost of the new disc brake (compared to a disc brake based on a composite carbon–carbon friction material) is expected to be lower by about 30%. [ABSTRACT FROM AUTHOR]

A brake disc decelerates the vehicle through friction with the brake pads. When the brake system is overheated, brake fade can occur, in which the friction coefficient drops significantly. Additionally, an over-heated brake system may cause vapor lock, in which the brake hydraulic fluid is vaporized. These phenomena can lead to the loss of braking power and cause a fatal accident. Therefore, brake systems must have stable braking and heat dissipation performance. Having through-holes and slits on the friction surface of the rotor has been adopted to improve the heat dissipation performance, but the holes become stress points and potentially cause cracks. Therefore, brake systems should be designed to have structural stability as well as good heat dissipation. In this study, finite element (FE) modeling was developed to analyze the structural stability and heat dissipation performance of a brake system, and structural and thermal simulations were performed in ANSYS, a CAE software package. In addition, to minimize concentrated stress and temperature, optimal design of the shape and pattern of holes and slits was carried out using PIAnO, an integrated optimal design software package. The first step of design optimization was performed while considering the shape and pattern of the disc holes and slits as design factors. Among the design factors, those with the largest effects on the objective functions were found and set as new design factors to perform the second step. The designs were compared to existing discs. Through the optimization presented in this paper, it is expected that the performance of the braking system will improve and the life of the brake parts will be increased. [ABSTRACT FROM AUTHOR]