scholarly journals Improvement in the brake disc design for heavy vehicles by parametric evaluation

2017 ◽  
Vol 231 (14) ◽  
pp. 1989-2004 ◽  
Author(s):  
Gaël Le Gigan
Keyword(s):  
Cast Iron ◽  
Fatigue Life ◽  
Thermal Loading ◽  
Grey Cast Iron ◽  
Brake Disc ◽  
Heavy Vehicles ◽  
Reference Case ◽  
Finite Element Software ◽  
Brake Discs ◽  
Grey Cast

Design of the brake disc geometry for a given brake disc material provides an opportunity for improvement in the fatigue life of the brake disc. High thermomechanical loads at braking lead to substantial local plastification and also induce tensile residual stresses in certain areas of the brake disc. This contributes to shortening of the fatigue life of the brake disc by possible initiation and growth of cracks. In the present paper, a simulation approach for evaluation of brake disc designs with respect to thermomechanical performance is developed and applied. Brake disc performance is analysed using commercial finite element software by employing a constitutive model for grey cast iron implemented in a Fortran subroutine. The thermal loading consists of consecutive severe braking cycles at a constant brake power and a constant speed, with cooling between the brake cycles. Based on a previous experimental study, three different assumptions are made regarding the spatial distribution of the thermal load at braking. A standard commercial brake disc made from grey cast iron having straight vanes is used as the reference case. Geometrical modifications are introduced in the ventilation arrangement using a design-of-experiments approach, studying both straight cooling vanes and different pillar layouts. A preliminary assessment of the fatigue life of the brake discs is carried out. The results indicate that the introduction of different pillar arrangements instead of straight vanes make it possible to decrease the mass of the brake disc by up to 13% or to increase the fatigue life of the brake disc by about 50%.

scholarly journals Thermomechanical fatigue of grey cast iron brake discs for heavy vehicles

2017 ◽  
Vol 233 (2) ◽  
pp. 453-467 ◽  
Author(s):  
Gaël Gigan ◽  
Viktor Norman ◽  
Johan Ahlström ◽  
Tore Vernersson
Keyword(s):  
Cast Iron ◽  
Fatigue Life ◽  
Thermomechanical Fatigue ◽  
Grey Cast Iron ◽  
Life Assessment ◽  
Model Parameters ◽  
Brake Disc ◽  
Fatigue Life Assessment ◽  
Brake Discs ◽  
Grey Cast

The development of fatigue life assessment models for vehicle components exposed to thermomechanical fatigue supports the establishing of adequate maintenance intervals that neither cause unnecessary vehicle downtime, nor jeopardize the function of the components. In modern automotive applications, braking is closely related to safety and is commonly performed with disc brakes. Failure here may result in structural damage or even breakdown and loss of lives. In the present work, the cyclic response of grey cast iron is analysed and the fatigue life of brake discs made from this material is studied by use of four different fatigue life assessment models: the Smith–Watson–Topper model, the Coffin–Manson model and two mechanism-based damage models. Results from isothermal and thermomechanical experiments on uniaxially loaded specimens are used for calibration of the models. Finally, the models are used to assess the life of a brake disc for a simulated brake dynamometer experiment. It is found that the fatigue model parameters that are calibrated using different sets of isothermal uniaxial test data show a substantial spread. A comparison with results from full-scale brake rig experiments shows that predictions by any of the models that have been calibrated using data from a well-designed thermomechanical test are in reasonable agreement with the estimated crack initiation phase for actual brake disc lives. It can be concluded that it is not sufficient to calibrate the studied fatigue life models using isothermal uniaxial tests for predictions of thermomechanical fatigue lives.

scholarly journals Simulation of thermal and mechanical performance of laser cladded disc brake rotors

2021 ◽  
pp. 135065012110091
Author(s):  
Nicholas Athanassiou ◽  
Ulf Olofsson ◽  
Jens Wahlström ◽  
Senad Dizdar
Keyword(s):  
Cast Iron ◽  
Laser Cladding ◽  
Adhesive Bonding ◽  
Mechanical Performance ◽  
Grey Cast Iron ◽  
Brake Disc ◽  
Particle Emissions ◽  
Brake Discs ◽  
Overlay Welding ◽  
Grey Cast

Disc brakes wear during braking events and release airborne particulates. These particle emissions are currently one of the highest contributors to non-exhaust particle emissions and introduce health hazards as well as environmental contamination. To reduce this problem, wear and corrosion-resistant disc coatings have been implemented on grey cast iron brake disc rotors by using various deposition techniques such as thermal spraying and overlay welding. High thermal gradients during braking introduce risks of flaking off and cracking of thermally sprayed coatings with adhesive bonding to the substrate. Overlay welding by laser cladding offers metallurgical bonding of the coating to the substrate and other benefits that motivate laser cladding as a candidate for the coating of the grey cast iron brake discs. This study aims to investigate the effect of laser cladding on the thermal and thermo-structural performance of the coated grey cast iron brake discs. Therefore, thermal and thermo-stress analysis with COMSOL Multiphysics 5.6 software is performed on braking events of grey cast iron brake discs as non-coated – reference and laser cladding coated with stainless steel welding consumables. The Results demonstrated that surface temperatures were more localised, overall higher in the laser cladded coating with over three times the stresses attained of reference grey cast iron discs. The output of the simulations has been compared by tests found in the literature. Laser cladding presented higher reliability and braking performance, nonetheless requiring the evaluation of its thermal impact on other system components.

scholarly journals Grey Cast Iron Brake Discs Laser Cladded with Nickel-Tungsten Carbide—Friction, Wear and Airborne Wear Particle Emission

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 621 ◽  
Author(s):  
Senad Dizdar ◽  
Yezhe Lyu ◽  
Conny Lampa ◽  
Ulf Olofsson
Keyword(s):  
Cast Iron ◽  
Tungsten Carbide ◽  
Wear Particle ◽  
Particle Emission ◽  
Grey Cast Iron ◽  
Wear Testing ◽  
Particle Analysis ◽  
Brake Disc ◽  
Grey Cast ◽  
Automotive Brake

Airborne wear particle emission has been investigated in a pin-on-disc tribometer equipped with particle analysis equipment. The pins are cut out from commercial powder metallurgy automotive brake pads as with and without copper content. The discs are cut out from a commercial grey cast iron automotive brake disc as cut out and as in addition to a laser cladded with a powder mix of Ni-self fluxing alloy + 60% spheroidized fused tungsten carbide and then fine-ground. Dry sliding wear testing runs under a contact pressure of 0.6 MPa, sliding velocity of 2 m/s and a total sliding distance of 14,400 m. The test results show both wear and particle emission improvement by using laser cladded discs. The laser cladded discs in comparison to the reference grey cast iron discs do not alter pin wear substantially but achieves halved mass loss and quartered specific wear. Comparing in the same way, the friction coefficient increases from 0.5 to 0.6, and the particle number concentration decreases from over 100 to some 70 (1/cm3) and the partition of particles below 7 µm is approximately halved.

scholarly journals Design and analysis of disc brake system in high speed vehicles

2021 ◽  
Vol 12 ◽  
pp. 19
Author(s):  
Anil Babu Seelam ◽  
Nabil Ahmed Zakir Hussain ◽  
Sachidananda Hassan Krishanmurthy
Keyword(s):  
Stainless Steel ◽  
Cast Iron ◽  
High Speed ◽  
Heat Dissipation ◽  
Optimal Choice ◽  
Grey Cast Iron ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Rotor ◽  
Grey Cast

Brakes are the most important component of any automobile. Brakes provide the ability to reduce or bring automobile to a complete stop. The process of braking is usually achieved by applying pressure to the brake discs. The main objective of this research paper is to propose an appropriate design and to perform analysis of a suitable brake rotor to enhance the performance of the high-speed car. The design of the brake disc is modelled using Solid works and the analysis is carried out using Ansys software. The analysis has been conducted by considering stainless steel and grey cast iron using same brake rotor design so that optimal choice of brake disc can be considered. The analysis considered involves static structural analysis and steady state thermal analysis considering specific parameters on brake rotor to increase the life of brake rotor. From the analysis it is found that the performance and life of disc brake depends upon heat dissipation. From the analysis results it can be concluded that grey cast iron has performed better as compared to stainless steel as this material has anti-fade properties which improves the life of the brake rotor.

Effects of Braking Pressure Distribution on Temperature Field and Stress Field During Braking

2019 ◽  
Author(s):  
Xianyu Zeng ◽  
Yu Liu ◽  
Xiandong Liu ◽  
Yingchun Shan ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Temperature Field ◽  
Fatigue Life ◽  
Stress Field ◽  
Pressure Distribution ◽  
Thermal Fatigue ◽  
Driving Safety ◽  
Brake Disc ◽  
Finite Element Software ◽  
Thermal Fatigue Life ◽  
Brake Discs

Abstract The braking performance of the vehicle directly affects the driving safety. Because of the different number of brake pistons and the wear of the brake pads, the distribution of braking pressure will be uneven, which will affect the distribution of temperature field and stress field during braking, then affect the thermal fatigue life of brake discs. Therefore, in this paper, the static tensile and compressive tests of gray cast iron HT200 samples cut from vehicle brake discs are carried out at −25°C, room temperature (25°C) and 500°C, and the stress-strain curves are analyzed to obtain mechanical properties such as strength limit, elastic modulus and so on at the temperature. Based on these parameters, the finite element software ABAQUS is used to simulate the single emergency braking condition. The thermal-structural coupling simulation of brake disc is carried out to study the influences of uneven brake pressure distribution on the temperature and stress fields of brake disc, which lays a foundation for the thermal fatigue life evaluation of brake disc.

The effects of cryogenic processing on the wear resistance of grey cast iron brake discs

Wear ◽  
2011 ◽  
Vol 271 (9-10) ◽  
pp. 2386-2395 ◽  
Author(s):  
R. Thornton ◽  
T. Slatter ◽  
A.H. Jones ◽  
R. Lewis
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Grey Cast Iron ◽  
Brake Discs ◽  
Grey Cast ◽  
Cryogenic Processing

scholarly journals Fatigue Life Assessment of Selected Engineering Materials Based on Modified Low-Cycle Fatigue Test

2013 ◽  
Vol 13 (1) ◽  
pp. 89-94
Author(s):  
M. Maj
Keyword(s):  
Cast Iron ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Ductile Iron ◽  
Low Cycle Fatigue ◽  
Grey Cast Iron ◽  
Life Assessment ◽  
Geometrical Parameters ◽  
Cycle Fatigue ◽  
Grey Cast

Abstract In this study, the mechanical tests were carried out on ductile iron of EN-GJS-600-3 grade and on grey cast iron of EN-GJL-250 grade. The fatigue life was evaluated in a modified low-cycle fatigue test (MLCF), which enables the determination of parameters resulting from the Manson-Coffin-Morrow relationship. The qualitative and quantitative metallographic studies conducted by light microscopy on selected samples of ductile iron with spheroidal graphite and grey cast iron with lamellar graphite (showing only small variations in mechanical properties,) confirmed also small variations in the geometrical parameters of graphite related with its content and morphological features.

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