Disc Brakes Research Articles

Modelling and Finite Element Analysis of Structural Modifications in Brake Pad and Disc to Suppress Squeal

Modelling and Finite Element Analysis of Structural Modifications in Brake Pad and Disc to Suppress Squeal

Methodology for determining the heat distribution in disc brakes of mine hoisting machines

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.

Enhancing reliability in estimating modal parameters for automotive disk Brakes: A comprehensive approach using the Eigensystem Realization algorithm and additional criteria

This paper investigates the challenges in accurately identifying and assessing vibration characteristics in automotive disk brakes, which, due to their geometric symmetry, exhibit closely spaced vibration modes. Understanding the damping characteristics is crucial due to their significant impact on dynamic stability and the potential onset of brake squeal, as damping directly influences the stability threshold and its uneven distribution can destabilize the system. Therefore, this study primarily focuses on the identification of modal parameters with an emphasis on the damping of disk brakes. Traditional Experimental Modal Analysis (EMA) techniques, which rely heavily on Frequency Response Function (FRF) measurements, encounter challenges in distinguishing closely spaced modes, thereby affecting the reliability of parameter estimation, particularly damping. These algorithms are primarily based on FRF measurements and are of multi-input – single-output type (MISO). In comparison to Operational Modal Analyses (OMA) algorithms, which are widely used in civil engineering and are of the multi-input − multi-output type and contain statistical tools for assessing the uncertainty of the estimate, EMA provides limited possibilities to assess the quality of estimating parameters. The primary contribution of this work is demonstrating that the Eigensystem Realization Algorithm (ERA), supplemented with indicators such as Extended Modal Amplitude Coherence (EMAC), Modal Phase Collinearity (MPC), and the Consistent Mode Indicator (CMI), offers a robust tool for accurate damping estimation. Additionally, the application of ERA to data originally acquired for frequency-based methods, specifically the Rational Fraction Polynomial (RFP) method, allows for a direct comparison of these two EMA algorithms using the same dataset. The results demonstrate that the proposed identification process effectively distinguishes system modes from those influenced by noise, providing a pathway to optimize test data acquisition and improve the accuracy of modal parameter estimation, especially in systems with closely spaced modes. The method can also serve as a tool for optimizing the acquisition of test data to improve the estimation of modal parameters, by varying the positions of input (SIMO) or by transitioning to MIMO identification to enhance the observability and controllability of closely spaced modes of disk brake.

Effect of shot peening equivalent impact force on fatigue crack growth behavior and fatigue life prediction of train brake discs

Brake discs, vital rail components, are subjected to intense friction and thermal cycling during braking, leading to surface cracking and fatigue failure. To address these issues, a novel equivalent impact force model for shot peening is proposed in this paper, with the aim of measuring the efficacy of shot peening and predicting the fatigue crack propagation life of brake discs with the assistance of an enhanced SSO algorithm. A finite element model of a cast steel brake disc simulated fatigue crack propagation under sinusoidal cyclic loading. The validity of the multiple projectile random impact model was experimentally confirmed by introducing a residual stress field into the disc surface using equivalent impact forces of 0.3, 0.4 and 0.5 MPa. This stress field was incorporated into the cyclic fatigue crack propagation model and compared with the FCGR results. Shot peening produced a compressive residual stress layer which increased in thickness with increasing impact force. The fatigue crack propagation rate was highly sensitive to the equivalent impact force, decreasing between 0.3 and 0.4 MPa and increasing from 0.4 to 0.5 MPa. Optimal crack propagation inhibition was at 0.4 MPa, which increased fatigue life by 457 % compared to non-peened discs. The improved SSO algorithm also achieved a 6 % increase in prediction accuracy.

Understanding the Actuation Point Stiffness of Electromechanical Drum Brakes

<div>Electromechanically actuated drum brakes are one interesting option for the realization of brake-by-wire systems for future electric vehicles. A key characteristic for the design and control of electromechanical brake actuators is the actuation point stiffness, as this quantity relates the actuation force to the required actuator position. The various known approaches for the control of electromechanical brakes, which primarily focus on disc foundation brakes, typically rely on the stiffness curve at least to some extent. A transfer of these approaches to drum brakes is not straightforward, because the actuation point stiffness for drum brakes is much more complex compared to disc brakes. In particular, a strong hysteretic behavior is observed for the standing drum and a considerable change of the stiffness and hysteresis can be observed for the rotating drum. Although drum brakes have been used for decades these effects have not been thoroughly discussed in literature, yet. Hence, this article proposes a minimal model, which gives a fundamental understanding of the stiffness characteristics of drum brakes. The relation to measured stiffness curves is discussed in detail to provide an in-depth understanding of the drum brake behavior. Additionally, prospect is given to a reduced complexity model that is suitable for online identification and control.</div>

Clamping Force Control of Electromechanical Brake Actuator Considering Contact Point between Friction Lining and Brake Disc

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.

Efficiency enhancement of bicycle anti-lock braking systems (ABS): Design and optimization of solenoid actuators through finite element analysis and performance simulation

The rising popularity of cycling underscores the need for enhanced safety, particularly under challenging braking conditions. This study introduces a novel high-power switch valve designed explicitly for Bicycle Hydraulic Disc Brakes (BHDBs), incorporating Hydraulic Anti-lock Braking Systems (ABS). Comprehensive Finite Element Analysis (FEA) modeling and subsequent optimization of an existing solenoid valve’s internal geometry were performed through 2D and 3D simulations to evaluate magnetic flux. The improved design achieved a maximum output force of 280 N with a linear stroke of approximately 3.5 mm. Notably, the enhanced system exhibited a 28% reduction in required current, from 5.0 to 3.6 A, a result validated through LabVIEW-equipped custom tests, which stress the credibility of the research. This study underscores significant advancements in high-power switch valves for BHDBs, promising enhanced braking efficiency and safety in high-performance, battery-powered bicycles. These findings not only promise enhanced safety for cyclists but also suggest the potential for broader application in energy-efficient and sustainable bicycle ABS technology, contributing to improved cyclist safety without compromising the environmental and health benefits of cycling. The potential impact of this research extends beyond the immediate context, offering insights that could be applied to other areas of technology and safety.

Magnetostrictive assisted free and forced vibration response of layered functionally graded circular plate with effect of prestress

One of the optimization requirements for improving the performance of magnetostrictive materials is prestress, which improves the magnetostriction coefficient. The influence of prestress on the fundamental frequencies and vibration suppression of a smart functionally graded circular plate is examined in the current work. The coupled differential equations regulating the motion are derived using Hamilton’s principle. This paper proposes using Kerr’s foundation as a flexible support structure for the disc braking system assembly. The Dirac-delta function and differential quadrature technique have been used to quantitatively simulate the forced vibration behaviour of a circular plate under moving loads. The accuracy and validity of the method used are tested by comparing numerical results to those that have already been published.

Friction and Wear Behavior of SiCp/Al Brake Disk Sliding Against Semimetallic Brake Pad under the Braking Condition of Urban Rail Vehicles

Due to their low density and exceptional wear resistance, SiCp/Al composites have great potential for brake materials used in trains. In this study, a newly developed SiCp/Al brake disk was fabricated by a powder metallurgy method. The friction and wear behavior of SiCp/Al brakes were investigated under extensive velocity ranges (40–220 km/h) according to the scale conversion rules. It is found that the matching tribocouple exhibits low wear loss, a reliable friction factor, and high heat resistance. The friction film maintains its continuity and stability at high braking speeds and temperatures, effectively protecting the surface of SiCp/Al composite materials from damage, minimizing wear, and stabilizing the friction coefficient. The excellent reliability of the lightweight SiCp/Al brake disk performance confirms its high technical feasibility to replace heavy iron and steel brake disks in urban rail vehicles that normally travel at 220 km/h.

A Comparative Evaluation of Conveyor Belt Disc Brakes and Drum Brakes: Integrating Structural Topology Optimization and Weight Reduction

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.

Characterization of temperature rise of carbon ceramic brake disc

Abstract Carbon ceramic can be utilized in the manufacture of new brake discs for trains with high speed as a new composite material. In this article, temperature rises of C/C-SiC discs in emergency braking are simulated using conducting the front-head train model containing brake discs, and simulation results are analyzed with those of steel brake discs. With 400 km/h braking speed, the temperature peak of carbon ceramic disc can reach 1098.56 K at 86.3 s under braking conditions of emergency.

Influence of thermal expansion and wear on the temperatures and stresses in railway disc brakes

Thermo-mechanical coupled systems are typically complex, however, the demand for analyses of this kind of multi-physics system is increasing, for example, accurately predicting the temperature and thermal stress of the railway disc brakes. However, many models ignore the phenomenon of thermal expansion and wear on brake pads. Therefore, their influence on the result is unclear. This research aims to investigate the effect of these two phenomena on the temperatures and stresses. These influences represent different heat flux input methods. Based on the finite element method (FEM), a three-dimensional (3D) transient thermo-mechanical model is built up. Three cases with or without thermal expansion and wear are conducted. The model is validated against measurement data. Simulation results show that thermal expansion and wear on the brake pads cause a 10% difference in the average temperatures of the brake discs, while a 257% difference in the maximum temperatures. As for the equivalent stresses (Von Mises stress), the difference can reach 3500%. Overall, this research builds a thermo-mechanical model and quantifies the effects of thermal expansion and wear on the temperatures and stresses of railway brake discs. The model can be transferred to other thermo-mechanical coupled multi-physics systems.

ANALYSIS OF THE BRAKE CALIPER POSITIONING IN VEHICLES

This paper aims to analyze the positioning of the brake caliper on vehicles, considering the most common situations, namely in front of or behind the brake disc. The positioning of the brake caliper on cars depends on the design and configuration of the brake system specific to each vehicle model. This positioning is determined by the engineers and designers responsible for the vehicle's safety, considering factors such as chassis geometry, weight distribution, desired braking performance, and other relevant technical factors. Generally, the brake caliper is located near the brake disc so that it can apply the necessary pressure to efficiently stop the wheels. Typically, in the case of disc brake systems, the brake caliper is positioned in front of the wheel, near the brake disc. There are cases where the positioning is behind the disc. Starting from this controversy, we considered it opportune to analyze the two cases on a stand that replicates the brake system. Thus, the two situations were analyzed using pressures of 2, 4, and 6 bars in the brake pipe. The variations in brake disc temperatures and braking distances were determined for each case to conclude the positioning of the caliper. The decision regarding the placement of the brake caliper in front of or behind the wheel is made by the vehicle manufacturer based on technical specifications and the desired performance of the brake system.

Design and Control of the Natural Frequency of Brake Discs in the Aspect of the Gray Cast Iron Production Process.

The results of research on the influence of the chemical composition of cast iron and its potential changes in the production cycle on the elastic properties and the correctness of numerical simulations of the natural frequency of ventilated brake discs are presented. The tests were carried out for three grades of gray cast iron with flake graphite with a eutectic saturation coefficient ranging from 0.88 to 1.01. A quantitative metallographic assessment of the pearlitic cast iron matrix and graphite precipitates was carried out, and the hardness and compressive/tensile strength of individual cast iron grades were determined, taking into account the limit contents of the alloying elements. Next, ultrasonic tests were performed, and the elastic properties of cast iron were determined. Based on the obtained data, a numerical modal analysis of brake discs was performed, the results of which were compared with the actual values of an FRF frequency analysis. The error of the computer simulations was estimated at approx. 1%, and it was found that the accuracy of the calculations of the first natural frequency did not depend on the dimensions (size) of the discs and the chemical composition of the cast iron from which they were cast. The functional relationships between the chemical composition of cast iron, its strength and elasticity and the first natural frequency of the disc vibrations were determined, and a database of the material parameters of the produced cast iron grades was developed. An implementation example showed the validation of the brake disc design with natural frequency prediction and demonstrated a high convergence of the experimental results with the simulated values. Using I-MR control cards, both the effectiveness of designing and predicting the natural vibrations of brake discs based on the implemented material database as well as the stability of the gray cast iron production and disc casting processes were confirmed.

Simulation and analysis of the electro-hydraulic coordinated system for the disc brake system in mining belt conveyor

The present study aims to investigate the dynamic performance of the disk hydraulic brake system in a mining belt conveyor. To achieve this, a simulation model of the hydraulic system for the belt conveyor is designed and constructed using AMESim. It is recognized that brake disk deformation can lead to brake shock, thus an ADAMS rigid-flexible coupling model for hydraulic disk brakes is established. Furthermore, the concept of rigid-flexible coupling mechanical systems is introduced into the hydraulic system to enable interaction between physical quantities. Use fuzzy logic rules to adjust parameters in Simulink, and in response to the suboptimal control of braking and acceleration, a compact non-model-based adaptive algorithm is incorporated into the conventional PID control algorithm. Employing mechanical modeling and multidisciplinary dynamic collaborative simulation technology, a simulation system integrating electromechanical and hydraulic aspects is developed for the disk hydraulic brake of belt conveyors. This system is employed to conduct simulation studies on the closed-loop control of braking disk speed and deceleration/acceleration for belt conveyors. The study findings reveal that the non-model-based adaptive PID control algorithm, in comparison to fuzzy PID, not only demonstrates quicker and more stable responses across various dynamic performance curves but also markedly reduces the axial oscillation amplitude of the braking disk under braking conditions.

Parametric analysis of the relationship between squeal and friction wear in motorcycle disc brakes

Squeal is a noise problem that affects all types of automotive brake systems and may affect the health of the population living in heavy traffic areas. Parameters such as pressure, friction, and Young’s Modulus are crucial in determining brake noise generation. Notably, wear on rubbing surfaces emerges as a key contributor to squeal, affecting the overall brake system functionality and necessitating frequent maintenance and parts replacement. This study conducted a detailed analysis of the influence of material and operational factors on squeal generation, specifically examining their relationship with friction wear in motorcycle disc brakes. To achieve this goal, a parametric study was conducted using finite element analysis software ANSYS. Thus, the study involved subjecting the geometry to static and modal analyses to verify the generation of unstable modes. Additionally, two models were built to analyze the influence of wear on noise: one with Archard wear activated, which calculated the worn volume, and another with this option disabled. The results of the study suggest that wear is a crucial parameter that must be considered in numerical models, given its significant impact on stability attributes. Moreover, since material and operational parameters play a substantial role in generating squeal noise, this study provides valuable insights into the causes and effects of brake noise, offering practical recommendations for mitigating this common problem in motorcycle disc brakes. The model developed also serves as foundational framework for configuring simulations for similar systems, automotive or train disc brake, to study the noise and lifespan of pads.

Preparation of a Gradient Anti-Oxidation Coating for Aircraft C/C Composite Brake Disc and Its High-Temperature In Situ Self-Healing Performance.

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.

Hazardous Elements in Road Dust from Petrol Stations in Rzeszów (Podkarpackie, Poland): Toxicological Assessment Using Field Portable X-ray Fluorescence (FP-XRF) as ‘White Analytical Technique’

AbstractSamples of road dust (RD) from petrol stations (n = 20) located in Rzeszów (Podkarpackie, Poland) were analysed to find potential markers of traffic-related pollution. The level (μg/g) of: Mo, U, As, Hg, Th, Pb, Ni, Cu, Cr, Be, Sr, Zr, Zn, Mn and Fe were measured using field portable X-ray spectroscopy (FP-XRF) as a direct, rapid and ‘white analytical technique’. Our research demonstrated for the first time the utility of using FP-XRF for environmental toxicological assessment of RD from petrol stations. The qualitative and quantitative composition of the dust samples tested provides valuable research material for creating and updating regulations and finding pollution hotspots such as petrol stations. It was possible to find potential markers of traffic-related pollution (e.g., Zr and Fe forms of disk brakes or brake pads). Certain elements of the study give ambiguous signals related to fuel distribution and road traffic. They can come from various sources of environmental contamination. The adoption of evidence-based policies to minimise pollution, conserve the environment, and protect the well-being of people living or working near gas stations is anticipated to be aided by these findings for policymakers, regulatory authorities, and stakeholders. Incorporating toxicological risk assessment framework, this study pioneers the investigation of human exposure to hazardous elements in RD, an in-depth evaluation of both carcinogenic and non-carcinogenic health risks associated with such exposure including lifetime average daily dose. Our findings contribute novel insights into the environmental toxicology of urban areas, emphasising the need for tailored interventions to mitigate these risks.

Research on the Influence of Floating Brake Pad Structure on the Friction Interface Performance of Disk Brake

The friction contact state of the brake friction interface of high-speed trains in the braking process affects the braking efficiency, which in turn affects the braking safety and the service life of the components. This article focuses on the heat and stress distribution at the friction interface under the action of a floating brake pad structure. A floating brake pad structure comprising two sets of spherical joint structure is introduced. The multibody structure and rigid–flexible coupling effects of the floating brake pad are considered. Furthermore, a full reproduction flexible thermomechanical coupling braking model in the floating brake pad structure is constructed. The accuracy of the model is validated by conducting tests on a 1:1-scale high-speed train brake test bench. The temperature and stress distribution of the fixed/floating brake pad structure at 80 km/h are studied accordingly. The results show that in accordance with the temperature outcomes derived from the simulation model, the observed temperature variations in the test results demonstrate an average error of 8.93%. The action of the floating brake pad resulted in a significant reduction of 36.99% in the maximum surface temperature of the brake pad, as well as a reduction of 30.91% in the maximum stress. The temperature of the brake disk surface is decreased by 32.01%, while the maximum stress experienced a decrease of 30.65%. The contact area of the friction interface is increased by 100%. The floating brake pad demonstrates a more uniform distribution and consistent gradient of temperature and stress across its friction interface in comparison to the fixed brake pad.

Analysis and Characterization of Composites for their potential use in Disc Brake Pad

Brake pads are crucial for vehicle safety, converting kinetic energy to halt motion. They come in types like organic, semi-metallic, ceramic, and metallic. Beyond automotive, brake pads find application in industries such as aerospace, railways, manufacturing, and wind energy for controlled deceleration and safety. This study is primarily concerned with the quality and appropriateness of ceramic brake pads for automotive applications, which are an essential aspect of braking systems for vehicles. The performance characteristics of ceramic brake pads are well established, and this study explores the variables affecting their quality. Under high pressure, brake pad samples are prepared in the study using Powder Metallurgy (PM), which guarantees superior mechanical qualities by removing interface bonding problems. The samples are then sintered at 2850. Hardness, temperature resistance, wear resistance, and Electron Dispersive Spectroscopy (EDS) analysis are all included in the evaluation to ascertain the make-up and distribution of the materials in the brake pad. EDS sheds light on the degree of sintering and the presence of reinforcements. Heat resistance is evaluated using controlled thermal testing, while wear resistance and hardness are determined through Rockwell hardness testing and wear tests, respectively. These measurements are validated for use in automotive disc braking systems for vehicles and motorcycles. The findings are more reliable thanks to statistical analysis done with MINITAB. The study highlights research gaps in environmentally friendly materials, emerging technology impacts, and long-term brake pad durability.