Braking Temperature Research Articles

An Analysis of the Coupling Between Temperature and Thermal Stress of Disc Brakes Based on Finite Element

Disc brakes have been more widely used in recent years due to its many merits such as fast heat absorption and dissipation, and resistance to water fade. Since it’s difficult to describe the failure of brakes under complex working conditions in only a few times of thermal-structural coupling simulations, this paper analyzed the coupling between temperature and thermal stress of disc brakes under multiple continuous braking conditions. At first, a 3D model of bus disc brake was built in ABAQUS, and its braking motion and dynamic parameters, heat flux density, convective heat dissipation coefficient, heat flux distribution coefficient, and other thermodynamic parameters were calculated. Then, the numerical simulation of the temperature field of disc brake and the coupling analysis of thermal stress under different braking conditions were completed. At last, experimental results gave the analysis results of the temperature distribution characteristics of brake disc surface, and the comparison and demonstration of the finite element analysis were conducted.

Effect of contact geometry on temperature field distribution and thermal buckling of an in-wheel disc brake system

ABSTRACT This paper aims to determine the effect of contact geometry on temperature distribution and thermal buckling in an in-wheel brake system. Numerical analysis is conducted to investigate the variation of temperature field distribution on the brake disc a different cover angles of the pad while maintaining the same moment of friction. Also, different positions of the pads on the disc are considered. To verify the simulation results, an analytical solution is derived. The results show that, for the same work done by the pads on the disc, the resulting temperature field distributions have various effects on the disc. Moreover, certain contact geometry was found to cause the braking temperature to exceed the critical temperature, leading to thermal buckling of the disc during braking.

Analytical Determination of the Brake Temperature Mode during Repetitive Short-Term Braking.

An algorithm to determine the maximum temperature of brake systems during repetitive short-term (RST) braking mode has been proposed. For this purpose, the intermittent mode of braking was given in the form of a few cyclic stages consisting of subsequent braking and acceleration processes. Based on the Chichinadze’s hypothesis of temperature summation, the evolutions of the maximum temperature during each cycle were calculated as the sum of the mean temperature on the nominal contact surface of the friction pair elements and temperature attained on the real contact areas (flash temperature). In order to find the first component, the analytical solution to the one-dimensional thermal problem of friction for two semi-spaces taking into account frictional heat generation was adapted. To find the flash temperature, the solution to the problem for the semi-infinite rod sliding with variable velocity against a smooth surface was used. In both solutions, the temperature-dependent coefficient of friction and thermal sensitivity of materials were taken into account. Numerical calculations were carried out for disc and drum brake systems. The obtained temporal variations of sliding velocity, friction power and temperature were investigated on each stage of braking. It was found that the obtained results agree well with the corresponding data established by finite element and finite-difference methods.

Android and Cloud-Based Application Development to Predict Remaining Age of Four-Wheeled Vehicle Brake Pad with Varied Driving Behaviour

One important component in a vehicle is the braking system. The main function of the braking system is to provide deceleration to stop the vehicle speed. One important part of the braking component is the brake lining. But to know the physical condition of the brake lining, it is necessary to dismantle the wheel and brake components. So that one of the initial stages of development is to make an application that can predict the remaining life of the brake lining without having to do the demolition. Therefore, this study will design the calculation with the physical condition monitoring approach of the brake lining itself. In addition, in this study, the author will try to find a relationship between driving behaviour and its effect on the wear rate of the brake lining. After testing the road with 3 different driving behaviours, it was found that the driver with eco behaviour would consume 0.42%, normal behaviour as much as 1.65% and sport behaviour as much as 44.96% of the thickness of the original brake lining. There was a significant result in sports driving behaviour because in this behaviour the braking pressure and temperature will be very high when compared to eco and normal. Furthermore, the application error which obtained from the application was higher than the other two behaviour.

Testing of Alternative Disc Brakes and Friction Materials Regarding Brake Wear Particle Emissions and Temperature Behavior

In this study, different disc brakes and friction materials are evaluated with respect to particle emission output and characteristic features are derived. The measurements take place on an inertia dynamometer using a constant volume sampling system. Brake wear particle emission factors of different disc concepts in different sizes are determined and compared, using a grey cast iron disc, a tungsten carbide-coated disc and a carbon ceramic disc. The brakes were tested over a section (trip #10) novel test cycle developed from the database of the worldwide harmonized Light-Duty vehicles Test Procedure (WLTP). First, brake emission factors were determined along the bedding process using a series of trip-10 tests. The tests were performed starting from unconditioned pads, to characterize the evolution of emissions until their stabilization. In addition to number- and mass-related emission factors (PM2.5–PM10), the particle size distribution was determined. Another focus was the evaluation of temperature ranges and the associated challenges in the use of temperature readings in a potential regulation of brake wear particle emissions. The results illustrate the challenges associated with establishing a universal bedding procedure and using disc temperature measurements for the control of a representative braking procedure. Using tungsten carbide coated discs and carbon ceramic discs, emission reduction potentials of up to 70% (PM10) could be demonstrated along the WLTP brake cycle. The reduction potential is primarily the result of the high wear resistance of the disc, but is additionally influenced by the pad composition and the temperature in the friction contact area.

Numerical Modeling of Mine Hoist Disc Brake Temperature for Safer Operation

The sustainable exploitation of raw materials, with improved safety and increased productivity, is closely linked to the development of mechanical mining installations. Mine hoists are designed for the transport of material, equipment and personnel between the mine surface and the underground. The mine hoist braking system is of paramount importance in its safe operation. Thus, for both drum and disc brake systems, the temperature of the friction surfaces is important for ensuring efficient braking, as exceeding the temperature threshold causes a decrease in the braking capacity. In this paper we present a numerical calculation model for the temperature of the braking disc of a mine hoist in the case of emergency braking. A real-scale model was built, based on the cable drive wheel and disc brake system of a hoisting machine used in Romania. Real material characteristics were imposed for the brake discs, the cable drive wheel and the brake pads. The simulation was performed for decelerations of 3, 3.5, 4 and 4.5 m/s2. The analysis shows that regardless of the acceleration and time simulated, the disc temperature reaches its maximum after 1.35 s of emergency braking. This value does not exceed the 327 °C limit where, according to previous studies, the braking power starts to fade. It means that the emergency braking is safe for the acceleration and masses under consideration, in the case of the studied mine hoist.

A modified uniformly distributed heat source method for predicting braking temperature of railway brake disc

ABSTRACT The current numerical method can only obtain the average temperature of the railway brake disc, which greatly reduces the predicting accuracy. Based on the uniformly distributed heat source method (UDHS Method), a more accurate and efficient method was proposed to predict the braking temperature by using a cosine function. This numerical method is valid as its results are in good agreement with the measurements from the full-scale rig test. After modification, the errors of the predicted maximum temperature are decreased from 5.73–6.72% to 3.47–5.07% at 40–100 km/h, and the temperature curves oscillate with a cosine form whose frequency is perfectly match with the curves from the thermal mechanical coupling method (TMC Method). The computational time of TMC Method is 74.19–665.61 times as much as that of UDHS Method, while the ratio of the modified method is reduced to 2.76–12.95 times.

Research on the Mechanical and Contact Performance of Marbles Screw Loading Device in Dry Disk Brakes

The marbles screw loading device is an important structural part in dry disk brakes. With the increasing of braking load and temperature, the material, mechanical and contact performance become a great challenging for the brake design. To better understand the performance, the mechanical and contact performance of marbles screw loading device is investigated. The performance is investigated under different braking load. Then, the influence of typical parameters including geometrical, friction coefficient and temperature on the effective stress and strain is researched. The explicit finite element method is employed to build the numerical simulation model. Numerical simulation result shows that the contact area centre locates on the outside of the brake. The disc groove with 15°has better performance. The residual stress is an increasing with respect to the temperature for the decreasing of material performance. The marbles screw loading device could be largely improved by adjust the geometrical dimensions.

Experimental investigation on performance and emission characteristics of CI engine fuelled with linseed oil and Ethyl-Tert-Butyl-Ether (ETBE) as additive

Increment in vitality exaction, serious outflow gauges, and consumption of the oil resources prompted chase for elective powers for traditional CI Engines. The examination prompts the exhibition and outflow attributes of CI engine fuelled with linseed oil and diesel is blended inside the mixing proportion B20, B40, B60, B80 with 5% ETBE. The Examination was controlled inside the four stroke single chamber diesel by changing the heap from 20% to 80%. The outcomes delineate that expansion of linseed oil increases the Brake thermal efficiency (BTE) with decrease in Brake Specific Fuel consumption (BSFC) and Temperature of Fumes Gas. Higher concentration of linseed oil within the blends also reduces the emission parameter but with an increment in the Hydro Carbon discharge. The expansion of ETBE in mix with diesel fuel has comparative impact thereto of expansion of unadulterated linseed oil in shifting extents, that increases the brake thermal efficiency with decrease in specific fuel utilization and fumes gas temperature, the impact on the emission characteristics by expansion of lamp oil brings about a lower CO, CO2, NOx and Smoke with an increase inside the HC discharge. The powerful blending of linseed oil and diesel yield agreeable outcome on the ignition qualities at lower load which shows signs of improvement on increasing the heap.

A Method to Account for Thermal Sensitivity and Friction Heat Resistance of Materials in Calculating Disc Brake Temperature Mode

This paper presents the system of equations of heat dynamics of friction and wear (HDFW) for the pad–disc tribosystems, accounting for the thermal sensitivity of materials and the dependence of the friction coefficient on the maximum temperature of the friction surface. The contact of two sliding layers with heat generation due to friction is chosen for simulation in the formulation of the corresponding thermal problem of friction. The solution to the HDFW system of equations is obtained using the method of lines. The calculations are performed for a cermet pad and a cast-iron disc. The variation in such interdependent characteristics as temperature, velocity, and friction coefficient is investigated in the braking process.

Experimental analysis in the test rig to detect temperature at the surface disc brake rotor using rubbing thermocouple

Brake failure is one of the causes of fatal accidents because the vehicle cannot be controlled properly. Therefore, research on improving brake safety needs to be assessed immediately. Brake temperature is used as an indicator of brake performance. If the temperature signal reads is different from the normal brake signal then it becomes an indication of a brake fault. How to measure the temperature of the rotating brake rotors and what sensors allow it to be used in real vehicles is the main question in this study. In this paper, there are two types of sensors that allow detecting brake temperature, namely rubbing thermocouple and a thermocouple sensor inserted in a pad with holes. The rubbing thermocouple sensor is expected to produce a higher heat because there is a friction effect between the rubbing steel and the rotor disc, whereas the sensor in the pad hole will show the real value. However, in the use of an actual vehicle, measuring the temperature by punching holes is not recommended because it can cause potential damage to the pad itself. When an infrared sensor is used, the installation is easier but this is not suitable because dirty conditions such as dust or sticky mud on the sensor surface will hinder the sensor reading. So the use of a rubbing thermocouple will be better in real vehicles. Therefore, the measurement of temperature by rubbing thermocouple must be made a correction factor that refers to the actual temperature. From the tests conducted, the results of measurements with rubbing thermocouple (T 4 ) can be converted to the equation T=–0,0058T 4 2 +2,7668T 4 –81,257. So how to make this equation can be proposed for the development of a safety warning system related to brake performance detection devices

Calculation of the Braking Temperature on a Brake Disc of Light Passenger Aircraft Using FEM and Newcomb Models

The friction of two bodies in relative motion is accompanied by several phenomena such as elevation of temperature. The aim of this work is to calculate the braking temperature of the brake disc of an aircraft during the landing phase, using a calculation code based on Finite Element Method (FEM) and the analytical method of Newcomb. This investigation uses two kinds of disc — full and real disc (original version mounted on the aircraft) — and three braking disc materials such as the cast irons FG15, FG20 and FG25. The result showed that the numbers of holes and slots existing in the real disc has no influence on the braking temperature compared to the full disc. On the other hand, all brake disc materials have almost the same thermal behavior. Both models, analytical and numerical, provided acceptable results.

Tribological and mechanical properties of biobased reinforcement in a friction composite material

Resumo This work presents the function of biobased (palm fiber) as reinforcement in brake pad materials. Reinforcement in brake lining improvise wear stability, wear resistance and friction optimization under a dynamic set of operating variables such as braking force, sliding speed, braking duration and braking temperature. Palm fiber have an attractive performance to cost ratio and have stimulated the idea of exploring their possible incorporation into brake pad composite materials. The effect of palm fiber loading on physical, mechanical and tribological properties of composite brake pad is evaluated. The palm fiber is loaded with 2%, 4%, 6%, 8%, 10% and 12% as an alternate of rockwool fiber by varying the pressure and speed in a pin on disc tribometer.By increasing the pressure, 8% and 10% show high friction stability at all speeds. The results show that by raising in the palm fiber quantity the hardness, specific gravity and heat swell increases, and also the loss on ignition and porosity decreases. The SEM descriptions of the composite indicated that the smallest micro voids occurred in the sample having low palm fiber. Finally, the effect of surroundings on the composites was investigated in salt water, water and oil. Palavras-chave: Palm Fiber, Wear, Friction Stability, Brakes, SEM

Modeling and Simulation Analysis of Wet Multi-Disk Service Braking System for Heavy Vehicles

A new type of charging valve with electro-hydraulic closed-loop feedback is designed, and a wet multi-disc dual-circuit service brake is built based on AMEsim. The charging and discharging characteristics of the accumulator are studied. The results show that under the condition of a medium-flow constant current source, the dual-circuit accumulator responds quickly, and a single charging can smoothly provide multiple stable discharge output. The response to the pressure output caused by the static structural parameters of the tandem braking valve and the pedal signal is studied. The results show that: the pedal signal can significantly change the brake pressure output, but the preload of the return spring is not apparent; the change of the cross-sectional diameter of the rear axle spool will cause the spool opening lags, and the difference in the spool diameter will cause the spool closing lags. The time response performance of single-axle braking and dual-axle braking is studied. The response from environmental factors such as road adhesion coefficient, slope, load, and brake cool modes to braking distance, braking deceleration, and braking temperature is studied. We establish a parameter ranges of braking safety zone and braking safety comfort zone. This study provides a comparison and reference to the design of a new charging valve and the performance test of the service braking system of heavy vehicles.

Simulation and experimental investigation of a multi-pole multi-layer magnetorheological brake with superimposed magnetic fields

This paper presents comprehensive investigations on a new multi-pole multi-layer magnetorheological (MR) brake. This unique design features MR working gaps set between two-layer individual coils. Independent current supply was proposed to generate more flexible braking torque and lower power consumption. In this article, an exploded-view drawing of the proposed MR brake was presented, and theoretical analyses of the braking torque and temperature characteristic were conducted. Then, finite element analysis was performed to verify the effect of the magnetic field superposition. A prototype MR brake was fabricated and tested to evaluate the magnetic field superposition, preliminary dynamic behavior, temperature and the performance of individual input current. The results show that the magnetic field superposition has much influence on the braking torque, and individual current supply results in different power consumption and torque ranges. Moreover, the dynamic response performance of this brake is less affected by the slip speed. Furthermore, the maximum steady-state slip power of the proposed brake is about 160 W, and the greater the slip power is, the faster the temperature increases. The results also have verified the correctness of the structure and magnetic circuit design.

Monetary evaluation of the reduced service life of asphalt pavements caused by the interlayer bond

The sustainability of asphalt pavements is highly depending on the quality of the interlayer bond (IB) between the different asphalt layers. In this project a complicated apparatus for cycling testing of the interlayer bond has been developed in order to determine the shear stiffness at the interface between asphalt layers taking into account the combined effect of varying and repeated traffic loading, acceleration and braking processes and temperature. A universal master function for analytical assessment of the IB shear stiffness has been established for any IB condition using the experimental results. Another function for completely fatigued IB has been developed as well. Both functions have been implemented into a finite element program to estimate the fatigue status of asphalt pavements for different bond qualities over a service life of 30 years using the German method for computational design according to RDO Asphalt 09. It has been succeeded to make a monetary evaluation of the reduced service life of asphalt pavements caused by interlayer bonds of different quality and to assess the construction cost penalty.

Simulation of Thermoelastic Problems with the Finite Element Method

AbstractDisc brakes convert kinetic energy into thermal energy in order to slow down vehicles. During the braking process enormous heat flows and temperature gradients occur in the system. Because heating leads to a change in shape for most materials, it is important to take the temperature and its influence into account during the design process. The interaction between the structure and the heat in disc brakes can be described with methods from thermoelasticity. To simulate thermoelastic behaviour the Finite Element Method is commonly used. The thermal and mechanical domain are taken into account by coupling the equation of motion and the heat equation. However, in transient analysis often the problem occurs of different time scales of the structural and thermal dynamics for many technically relevant materials, like steel. For metallic materials the time constant of structural dynamics is much smaller than those of thermal dynamics. This complicates an efficient transient simulation. In the present work the implementation of a Finite Element Method in thermoelasticity and associated investigations are shown. The method is applied to various parts and load cases. Also different approaches to deal with the different time scales will be shown. Heuristic methods like mass‐scaling as well as more mathematically oriented approaches like model order reduction are presented.

Tribological performance of B4C modified C/C-SiC brake materials under dry air and wet conditions

In this work, boron carbide (B4C) was selected as additive to improve the tribological performance of C/C-SiC brake materials. It contained four phases (C, B4C, Si and SiC) in B4C modified C/C-SiC (C/C-B4C-SiC) brake materials. Its wear rates were much less than that of C/C-SiC, especially at high braking speeds. The introduction of B4C particles could reduce the braking temperature. During the braking process, B4C in the material can be oxidized to B2O3. The flow of B2O3 could cover the interface of carbon fiber and PyC to prevent them from oxidation and thereby reduce the oxidative wear of the brake materials. Under wet conditions, the braking property of C/C-B4C-SiC brake materials did not degrade, whereas the braking process was found to be stable.

Effect of Heat Treatment on Crack Propagation and Performance of Disk Brake with Cross Drilled Holes

A vehicle disk brake, which has cross drilled hole patterns on a frictional surface for improving cooling and braking performance, has propensity to cause crack problem under the harsh braking condition. In this study, the finite element analysis by using ABAQUS was adopted to investigate a cause of crack occurrence by the thermo-mechanical phenomenon around drilled hole patterns. As a remedy of the crack generation, the disk brake rotor with stress relieving and ferritic nitrocarburizing was prepared and tested on brake dynamometer in harsh condition. The test result was examined in terms of pad wear, the braking torque variation, the braking temperature changes, the crack initiation timing, and the crack propagation speed. As a test result, the disk after heat treatment showed 3.61 % higher average braking temperature than the disk without heat treatments, to suggest decreased heat dissipation performance, however, it also showed 14 % lower pad wear amount, and 0.1 % smaller braking torque variance than the disk without heat treatments, to stand for improved contact characteristics. Also, the heat treated brake rotor showed 51.3 % lower crack propagation rate which is considered as proper countermeasure of the fracture phenomenon at the edge of cross drilled hole.

Multi-Field Coupling Analysis and Demagnetization Experiment of Permanent Magnet Retarder for Heavy Vehicles (MAY 2018)

A new permanent magnet retarder (PMR), which based on the principle of eddy-current braking, is proposed as an auxiliary braking apparatus for heavy vehicles. Its braking torque can be stepless adjusted by the adjustment mechanism. A multi-physics field coupling model of the retarder was established, which includes electromagnetic field, thermal field, and fluid field. The distributions of the three fields were calculated using the finite-element method. To predict the demagnetization of the permanent magnet, a new analysis method of the permanent magnet irreversible demagnetization is proposed, which uses the dynamic air-gap flux density simulated under various temperature B-H curves and the relationship between the braking torque, as well as the square of air-gap flux density. The braking torque and temperature rise of the PMR were tested on the bench. The bench test results show that the braking torque calculated by the multi-physics coupling method agrees better with the experimental data, and the high-temperature irreversible demagnetizations of the permanent magnet occurred by the enormous heat generated during continuous braking. The vehicle test results show that the braking distance can be shortened by 34% after using the PMR, and the braking deceleration is increased by 1.05 m/s 2 . The proposed PMR can meet the requirements of auxiliary braking for heavy vehicles.