scholarly journals Wear Induced Failure of Automotive Disc Brakes—A Case Study

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4214 ◽  
Author(s):  
Ali Mohammadnejad ◽  
Abbas Bahrami ◽  
Majid Goli ◽  
Hossein Dehbashi Nia ◽  
Peyman Taheri
Keyword(s):  
Wear Mechanisms ◽  
Optical Microscope ◽  
Outer Edge ◽  
Brake Disc ◽  
Disc Brake ◽  
Root Cause ◽  
Disc Brakes ◽  
Pin On Disc ◽  
Radial Cracks ◽  
Worn Surface

This paper investigated a failure in a ventilated disc brake in an automobile. The failed brake disc had been in service for approximately 10 years. The observed failure was in the form of radial cracks that appeared to have initiated at the outer edge of the disc brake. The cracks were rather straight with no branching. Optical microscope, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to study the microstructure of the failed disc. Vickers microhardness test was also used to evaluate the hardness of the samples. Results showed that the root cause of crack formation, in this case, was related to the excessive wear in the brake disc. Different wear mechanisms, namely abrasive and adhesive wear, were recognized in the failed specimen. Moreover, the worn surface in some areas was covered with fine oxide particles. These particles appeared to have a significant contribution toward abrasion. To further understand the wear mechanisms, pin-on-disc experiments were also conducted on the samples. Results of the pin-on-disc experiments were compared and correlated to the results obtained from the failed brake disc.

scholarly journals Influence of Disc Temperature on Ultrafine, Fine, and Coarse Particle Emissions of Passenger Car Disc Brakes with Organic and Inorganic Pad Binder Materials

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1060
Author(s):  
Hartmut Niemann ◽  
Hermann Winner ◽  
Christof Asbach ◽  
Heinz Kaminski ◽  
Georg Frentz ◽  
...  
Keyword(s):  
Systematic Variation ◽  
Coarse Particle ◽  
Brake Disc ◽  
Disc Brake ◽  
Aging Effects ◽  
Passenger Car ◽  
Particle Emissions ◽  
Inorganic Binder ◽  
Disc Brakes ◽  
Pm10 Emissions

Passenger car disc brakes are a source of ultrafine, fine, and coarse particles. It is estimated that 21% of total traffic-related PM10 emissions in urban environments originate from airborne brake wear particles. Particle number emission factors are in the magnitude of 1010 km−1 wheel brake during real-world driving conditions. Due to the complexity of the tribological processes and the limited observability of the friction zone between brake disc and pad, the phenomena causing particle emission of disc brakes are only partially understood. To generate a basis for understanding the emission process and, based on this, to clarify which influencing variables have how much potential for reduction measures, one approach consists in the identification and quantification of influencing variables in the form of emission maps. The subject of this publication is the influence of disc brake temperature on ultrafine, fine, and coarse particle emissions, which was investigated with a systematic variation of temperature during single brake events on an enclosed brake dynamometer. The systematic variation of temperature was achieved by increasing or decreasing the disc temperature stepwise which leads to a triangular temperature variation. Two types of brake pads were used with the main distinction in its chemical composition being organic and inorganic binder materials. The critical disc brake temperature for the generation of ultrafine particles based on nucleation is at approximately 180 °C for pads with an organic binder and at approximately 240 °C for pads with inorganic binder materials. Number concentration during those nucleation events decreased for successive events, probably due to aging effects. PM10 emissions increased by factor 2 due to an increase in temperature from 80 °C to 160 °C. The influence of temperature could be only repeatable measured for disc brake temperatures below 180 °C. Above this temperature, the emission behavior was dependent on the temperature history, which indicates also a critical temperature for PM10 relevant emissions but not in an increasing rather than a decreasing manner.

scholarly journals Bicycle Disc Brake Thermal Performance: Combining Dynamometer Tests, Bicycle Experiments, and Modeling

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 100
Author(s):  
Ioan Feier ◽  
Joseph Way ◽  
Rob Redfield
Keyword(s):  
Thermal Model ◽  
Normal Force ◽  
Field Trials ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pad ◽  
Brake Pads ◽  
Disc Brakes ◽  
Friction Curve ◽  
Friction Performance

High-power bicycle disc braking can create excessive temperatures and boiling brake fluid, resulting in performance degradation and damage. The goal of this work is to understand brake friction performance and thermal behavior for bicycle disc brakes. A previously described disc braking dynamometer is used to assess brake pad performance of sintered metallic brake pads, organic brake pads, and ‘power’ organic pads in up to 400 W of braking power. The friction coefficient is found to be dependent on both temperature and normal force. Friction curve fits are provided for temperatures between 300 K and 550 K. Organic and ‘power’ organic pads are found to have similar behavior, and have higher friction coefficients compared to metallic pads. Further, brakes on an instrumented bicycle are tested in outdoor field trials during downhill descent. A MATLAB thermal model successfully predicts the downhill field brake disc temperatures when using the friction data curve fits.

The Design of Disc Brake for Mine Hoist in Civil Engineering

2012 ◽  
Vol 568 ◽  
pp. 212-215 ◽  
Author(s):  
Hai Tao Zhang ◽  
Ying Jun Dai ◽  
Yu Jing Jia ◽  
Guang Zhen Cheng
Keyword(s):  
Salt Spray ◽  
Outer Cylinder ◽  
Positive Pressure ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pads ◽  
Disc Brakes ◽  
Cylinder Piston ◽  
Set Up ◽  
Mine Hoist

This article will describe the research status and the features of control system of the disc brakes of mine hoist. The disc brakes consist of body, outer cylinder, cylinder, piston, ring, disc springs, plunger, gate disk and other components. The disc brakes use the pre-load of disc springs to force the piston to move towards the brake disc, push the brake pads out, then the brake pads and drum brake disc contact and resulting in positive pressure, then the formation of friction produce a braking torque. When the brake system loose pads, the cylinder is filled with the pressure oil, which make the piston compresses the disc springs, and promote the brake pads to move back and then left brake disc, remove the braking force. The hydraulic circuit of the braking system chooses two-way parallel oil and four oil cylinder brake. A slip road set up a one-way throttle, making the slip road brake slightly delayed, which will achieve two stage braking and make work more stable. This disc brake is normally closed, which means when the hoist does not work, the brake is in the state of braking to prevent the occurrence of accidents. This brake is safe, reliable and sensitive in action. The materials of brake pads is rigid asbestos plastic, which have stable friction coefficient, good wear resistance, is not sensitive to the aqueous medium and salt spray,it has flexible installation location, and it is easy to use, adjust and maintain.

scholarly journals Design and Analysis of Solid and Cross-Drilled Disc Brake Rotors

10.29007/g49k ◽  
2018 ◽  
Author(s):  
Jimit Vyas ◽  
Mahesh Zinzuvadia ◽  
Mohammedilyas I. Kathadi
Keyword(s):  
Temperature Distribution ◽  
Numerical Analysis ◽  
Thermal Stresses ◽  
Paper Analysis ◽  
Heat Energy ◽  
Brake Disc ◽  
Disc Brake ◽  
Disc Brakes ◽  
Brake Rotor ◽  
Brake Rotors

In this paper analysis of automotive disc brake rotor is carried out with the help of ANSYS 17.1 Academic software. Disc brakes operate on the principle of friction by converting the kinetic energy of the vehicle into heat energy at the contact between disc and pads. The main objective of a disc brake rotor is to store this generated heat energy and dissipate it into the environment as soon as possible. This heat rapidly increases the temperature of the disc at the rubbing surface, resulting in thermal stresses in the components of the brake. Thermal behavior of solid and cross drilled brake disc rotors is studied. For numerical analysis commercially available tool ANSYS is used to determine temperature distribution in the disc.

scholarly journals Formation of Nanocrystallized Structure in Worn Surface Layer of T10 Steel against 20CrMnTi Steel during Dry Rubbing

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Xin Wang ◽  
Xicheng Wei ◽  
Jing Zhang ◽  
Rongbin Li ◽  
Meng Hua ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Sliding Friction ◽  
Normal Load ◽  
Nanocrystalline Structure ◽  
Wear Test ◽  
Optical Microscope ◽  
Surface Layers ◽  
Transmission Electron ◽  
Pin On Disc ◽  
Worn Surface

T10 steel slid against 20CrMnTi steel on a pin-on-disc wear test rig. Optical Microscope (OM), scanning electron microscope (SEM), and High Resolution Transmission Electron Microscope (HRTEM) methods were used to analyze the microstructures in the worn surface layers. The microstructures in the worn surface layers of pins and discs were all severely plastically deformed. Furthermore, the ultrafine and even nanoferrite structure (10 nm to 100 nm) was observed when the normal load reached 60 N. The mechanism of forming nanocrystalline structure in the sliding friction induced deformation layer (SFIDL) was elucidated as the result of the simultaneous and recursive actions of (i) severe shear deformation and (ii) friction heat on the contact surface.

Numerical Modeling and Simulation Analysis of Temperature Field of Disc Brake on Trains

2011 ◽  
Vol 199-200 ◽  
pp. 1492-1495 ◽  
Author(s):  
Guo Shun Wang ◽  
Rong Fu ◽  
Liang Zhao
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
High Speed ◽  
Large Scale ◽  
Working Condition ◽  
Constant Speed ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pad ◽  
Finite Element Software

The simulation calculation on the temperature field of the disc brake system on high-speed trains under the working condition of constant speed at 50Km/h is made. A steady-state calculation model is established according to the actual geometric size of a brake disc and a brake pad, and the analog calculation and simulation on the temperature field of the brake disc and the brake pad by using the large-scale nonlinear finite element software ABAQUS are carried out. The distribution rules of the temperature field of the brake disc and the brake pad under the working condition of constant speed are made known. The surface temperature of the brake disc at friction radius is the highest, with a band distribution for temperature. There exists a temperature flex point in the direction of thickness, of which the thickness occupies 15% of that of the brake disc; due to the small volume of the brake pad, the temperature gradient of the whole brake pad is not sharp, and larger temperature gradient occurs only on the contact surface.

scholarly journals Tribological Characteristics of the Magnesium Matrix-Glassy Carbon Particles Composite Manufactured by Different Casting Methods

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Anita Olszówka-Myalska ◽  
Jerzy Myalski ◽  
Bartosz Hekner
Keyword(s):  
Glassy Carbon ◽  
Sliding Friction ◽  
Particulate Composite ◽  
Magnesium Matrix ◽  
Cast Material ◽  
Carbon Particles ◽  
Die Cast ◽  
Pin On Disc ◽  
Worn Surface ◽  
Gravity Cast

A particulate composite with a magnesium matrix (Mg3Al) and glassy carbon particles (GCp) obtained under industrial conditions from a gravity cast and pressure die cast suspension was examined. The influence of the casting procedure on the microstructure and mechanical properties was revealed. Sliding friction tests by the pin-on-disc method for different loads (2.3, 5, and 9.3 N) and speeds (0.06, 0.09, and 0.14 m/s) were performed. Regardless of the technology, the sliding friction coefficient’s value strongly depended on the load and speed. Its value was changing (0.35–0.13) and was usually higher for the pressure die cast material, yet the wear resistance of the composite processed in that way was considerably better compared with the gravity cast. The results of the worn surface observation by SEM with EDS showed an influence of the initial Mg3Al-GCp composite’s microstructure on the processes of its wear.

A Comparative Study of Tribological Behavior of Steel Sliding Against WC Under Mineral and Biodegradable Oil Lubrication

2012 ◽  
Author(s):  
Anup Darshan ◽  
UmaMaheshwera Reddy Paturi ◽  
Narala Suresh Kumar Reddy ◽  
Srinivasa Prakash Regalla
Keyword(s):  
Tribological Properties ◽  
Positive Impact ◽  
Research Work ◽  
Mineral Oil ◽  
Optical Microscope ◽  
Machining Processes ◽  
Alternative Source ◽  
Pin On Disc ◽  
Steel Disc ◽  
Machining Operations

Now a days for machining operations apart from good tribological properties, the lubricant is also expected to be non-hazardous and non-polluting. When considering the ecological and environmental aspects in machining processes, the use of biodegradable oil can be an alternative source of lubricant due to its positive impact to employee health and environmental pollution. In this regard, our research work uses vegetable based cutting fluids developed from canola and sunflower oil, in an attempt to provide an eco-friendly environment. Experiments are carried out on a pin-on-disc tribometer with tungsten carbide (WC) pin against AISI 4340 steel disc for different sliding times under different environments, thus simulating the machining environment. The tribological properties, wear and friction of vegetable based oils were comparatively investigated with a commercially available mineral oil. Wear tracks and roughness profiles of test specimens were compared by using optical microscope and profilometer respectively. Results indicated that vegetable based canola oil demonstrated excellent tribological properties compared to that of commercial mineral oil.

Braking performance of a novel frictional-magnetic compound disc brake for automobiles

2018 ◽  
Vol 233 (10) ◽  
pp. 2443-2454 ◽  
Author(s):  
Yan Yin ◽  
Jiusheng Bao ◽  
Jinge Liu ◽  
Chaoxun Guo ◽  
Tonggang Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temperature Rise ◽  
Friction Material ◽  
Maximum Temperature ◽  
Interface Temperature ◽  
Disc Brake ◽  
Braking Performance ◽  
Maximum Temperature Rise ◽  
Disc Brakes ◽  
Braking Torque

Disc brakes have been applied in various automobiles widely and their braking performance has vitally important effects on the safe operation of automobiles. Although numerous researches have been conducted to find out the influential law and mechanism of working condition parameters like braking pressure, initial braking speed, and interface temperature on braking performance of disc brakes, the influence of magnetic field is seldom taken into consideration. In this paper, based on the novel automotive frictional-magnetic compound disc brake, the influential law of magnetic field on braking performance was investigated deeply. First, braking simulation tests of disc brakes were carried out, and then dynamic variation laws and mechanisms of braking torque and interface temperature were discussed. Furthermore, some parameters including average braking torque, trend coefficient and fluctuation coefficient of braking torque, average temperature, maximum temperature rise, and the time corresponding to the maximum temperature rise were extracted to characterize the braking performance of disc brakes. Finally, the influential law and mechanism of excitation voltage on braking performance were analyzed through braking simulation tests and surface topography analysis of friction material. It is concluded that the performance of frictional-magnetic compound disc brake is prior to common brake. Magnetic field is greatly beneficial for improving the braking performance of frictional-magnetic compound disc brake.

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