Abstract:The method presented in this work intends to analyze drum brake design parameters of a light duty automotive drum brake system. The main objective of this work is to correlate brake materials and unstability parameters to identify which condition will effectively reduce squeal propensity. The methodology involves (a) the finite-element method of the brake components, namely, drum, shoes, and frictional linings, (b) static calculations to get a pre-stress state around which (c) is computed the complex eigenvalu… Show more
“…Then, aforementioned, the simulation of a static structural analysis for a brake disc is based on the occurrence of a stopping, where force is applied generating a friction contact of the pads on the disc (Figure 2), for this analysis, the disc was considered rotating with 79.37 rad/s (=20 km/h). For the eigenvalue and eigenvector extraction, the influences of the inertia and rigidity must be taken in account, 2–4,19 making the equation as follows:…”
Section: Methodsmentioning
confidence: 99%
“…As seen by others works, the higher contact pressures (warm colors) happen near the edge in direction of the rotational movement, also, large blue parts, indicating low pressure, can be seen in the other end of the edge thanks to its singular pad geometry, it is also explained that this variating pressure distribution is evidence of instability that can generate squeal. 2–4,20–22 Figure 3.Static structural analysis results of disc brake contact pressure.…”
Section: Methodsmentioning
confidence: 99%
“…For the modal analysis, the same inputs as before were chosen, a pressure of 4.27 MPa on each pad and rotational velocity of 79.37 rad/s on the disc, the movement equation that explain this analysis can have its damping factor neglected, not having issues on results, 2–4,19 giving the equation:…”
Section: Methodsmentioning
confidence: 99%
“…It has been shown that this can even occur if the friction coefficient is constant. 2–4,14–16 It has also been demonstrated that the brake squeal occurs only when at least two of these events happen simultaneously. 2–5,10…”
Brakes are a critical component of automobiles, responsible for converting kinetic energy into heat and vibration. The phenomenon of brake squeal, which produces uncomfortable noises, has been extensively studied in both drum and disc brakes. Many studies have evaluated the influence of material and operational parameters on brake instability to reduce squeal. However, the effect of temperature, a key factor in brake performance, is often overlooked. This study aims to fill this gap by analyzing a single rear-axle disc brake from an off-road single-seater vehicle using a parametric approach. Two branches were developed in ANSYS software. The first branch consisted of a finite element model of the brake with disc, pads, and backplates. A static structural analysis was performed to simulate a real braking pressure situation, and the resulting pre-stress state was used to conduct complex modal analysis, which extracted eigenvalues and values responsible for stability. The second branch involved a transient thermal simulation before the static analysis, also considering a real braking situation, to create a gradient of temperature and change component pre-stress reactions accordingly. A design of experiments process was used to explore geometric, thermal, and operational variables. The results showed that temperature and its parameters (convection and emissivity coefficient) increase brake squeal. Thus, considering the effect of temperature is crucial when evaluating brake instability, and optimizing temperature control can help reduce brake squeal, improving safety and comfort for drivers and passengers.
“…Then, aforementioned, the simulation of a static structural analysis for a brake disc is based on the occurrence of a stopping, where force is applied generating a friction contact of the pads on the disc (Figure 2), for this analysis, the disc was considered rotating with 79.37 rad/s (=20 km/h). For the eigenvalue and eigenvector extraction, the influences of the inertia and rigidity must be taken in account, 2–4,19 making the equation as follows:…”
Section: Methodsmentioning
confidence: 99%
“…As seen by others works, the higher contact pressures (warm colors) happen near the edge in direction of the rotational movement, also, large blue parts, indicating low pressure, can be seen in the other end of the edge thanks to its singular pad geometry, it is also explained that this variating pressure distribution is evidence of instability that can generate squeal. 2–4,20–22 Figure 3.Static structural analysis results of disc brake contact pressure.…”
Section: Methodsmentioning
confidence: 99%
“…For the modal analysis, the same inputs as before were chosen, a pressure of 4.27 MPa on each pad and rotational velocity of 79.37 rad/s on the disc, the movement equation that explain this analysis can have its damping factor neglected, not having issues on results, 2–4,19 giving the equation:…”
Section: Methodsmentioning
confidence: 99%
“…It has been shown that this can even occur if the friction coefficient is constant. 2–4,14–16 It has also been demonstrated that the brake squeal occurs only when at least two of these events happen simultaneously. 2–5,10…”
Brakes are a critical component of automobiles, responsible for converting kinetic energy into heat and vibration. The phenomenon of brake squeal, which produces uncomfortable noises, has been extensively studied in both drum and disc brakes. Many studies have evaluated the influence of material and operational parameters on brake instability to reduce squeal. However, the effect of temperature, a key factor in brake performance, is often overlooked. This study aims to fill this gap by analyzing a single rear-axle disc brake from an off-road single-seater vehicle using a parametric approach. Two branches were developed in ANSYS software. The first branch consisted of a finite element model of the brake with disc, pads, and backplates. A static structural analysis was performed to simulate a real braking pressure situation, and the resulting pre-stress state was used to conduct complex modal analysis, which extracted eigenvalues and values responsible for stability. The second branch involved a transient thermal simulation before the static analysis, also considering a real braking situation, to create a gradient of temperature and change component pre-stress reactions accordingly. A design of experiments process was used to explore geometric, thermal, and operational variables. The results showed that temperature and its parameters (convection and emissivity coefficient) increase brake squeal. Thus, considering the effect of temperature is crucial when evaluating brake instability, and optimizing temperature control can help reduce brake squeal, improving safety and comfort for drivers and passengers.
“…Therefore, the real-time fault diagnosis [3] of hydraulic braking system is a necessary requirement for the development of vehicle intelligence. The research shows that in the process of braking, if the brake pressure from different wheel cylinders is uneven, one of the most direct manifestations is the increase of brake vibration and noise [4]. When the braking force interacts with the inertial force of the vehicle itself, excessive or small local load will cause abnormal vibration of friction pairs due to mutual impact, which belongs to uneven braking [5,6].…”
The friction vibration signal corresponding to different fault types of brakes is significantly different, thus a hydraulic disc brake fault diagnosis and judgment scheme based on vibration signal detection was proposed and validated in the paper. According to the composition and electric control principle of hydraulic brake, the vibration signal detection and brake pressure control strategies were established. The key hardware and isolation circuit of the detection system were designed, which can effectively improve the stability and anti-interference ability in the process of vibration data acquisition and transmission with SPI and CAN bus communication scheme. In order to eliminate noise interference in friction vibration signal and improve the accuracy of fault diagnosis with advantage, wavelet threshold denoising method was applied to brake disc vibration signal processing. The denoised signal can be obtained by inverting the selected wavelet coefficients to separate the useful components of the signal from the invalid noise. For the research on the correlation between fault types and vibration signal characteristics, a friction vibration test bench for hydraulic braking system was built to obtain and process the output signal from vibration sensor. The frequency spectrum response laws of vibration signals were compared and analyzed when the brake disc was normal and had surface defects, including microcracks, excessive wear and fatigue peeling. The external parameters such as brake pressure and spindle speed were keeping constant, thus eliminating the influence of working factors on vibration characteristics. In order to study the influence of brake pressure failure on friction vibration, the variation law of vibration signal is compared and analyzed under the condition of hydraulic valve leakage and pressure maintaining failure. The results show that the friction vibration signal can be used as an effective basis for judging the surface defects and brake pressure faults of brake discs. Under the condition of wavelet threshold denoising, accurate and effective vibration parameters can be obtained, which is of great significance to the safety and reliability of the braking system.
Drum brakes may failure due to overheating in the contact area during frequent braking. This research takes the honeycomb structure with excellent heat dissipation and strength as the biomimetic object, and processes different biomimetic patterns on the surface of the brake pad. Using a self-made drum brake test bench, the changes in braking duration and surface temperature of different biomimetic pattern brake pads under emergency braking and repeated braking tests at different braking intervals are studied. The experimental results indicate that the braking duration of patterned brake pad is 7.82%~11.8% shorter than that of normal brake pads. Although the temperature of normal brake pads is lower at the end of braking, as the heat dissipation cycle prolongs, patterned brake pads exhibit faster heat dissipation, with honeycomb patterns having better heat dissipation than circular and square patterns. Using the least squares method, it was calculated that when the braking cycles were greater than 10.3s, 12.0s, and 14.5s, the braking heat dissipation effect of honeycomb, circular, and square brake pads was better than that of normal brake pads. These results validate that honeycomb patterned brake pads can alleviate the occurrence of thermal degradation in drum brakes.
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