Effect of Material and Dimensional Homogeneity on Thermo-mechanical Deformation of Brake Discs during High-speed Braking

2015 ◽  
Vol 8 (2) ◽  
pp. 293-301 ◽  
Author(s):  
Toshikazu Okamura
Keyword(s):  
High Speed ◽  
Mechanical Deformation ◽  
Brake Discs ◽  
Dimensional Homogeneity

Failure Mechanisms of TGV Brake Discs

2007 ◽  
Vol 345-346 ◽  
pp. 697-700 ◽  
Author(s):  
Gérard Degallaix ◽  
Philippe Dufrénoy ◽  
Jonathan Wong ◽  
Paul Wicker ◽  
Frédéric Bumbieler
Keyword(s):  
High Speed ◽  
Thermal Loading ◽  
Test Bench ◽  
Infrared Camera ◽  
Second Step ◽  
Brake Disc ◽  
Disc Brakes ◽  
Brake Discs ◽  
High Speed Trains ◽  
Very High

The CRISFIS project (supported by ADEME agency) consists in jointly studying the squealing and cracking aspects of the high power disc brakes for TGV very high speed trains. This paper deals with the progress concerning the cracking part. An experimental and modelling strategy is adopted in order to better understand and predict brake disc cracking. Braking tests conducted on an industrial scale-one test bench are presented. In a first step, the influence of the pad-type on the thermal loading applied to the disc is studied by means of an infrared camera and thermocouples embedded in the pads and in the disc. In a second step, the thermal maps extracted from thermographic monitoring are used as input data for thermal-mechanical calculations. Finally, the results of modelling and tests are compared to the damage observed on the brake discs.

Dynamic response analysis of the brake disc of a high-speed train with wheel flats

2021 ◽  
pp. 095440972110317
Author(s):  
Zhiwei Wang ◽  
Jiliang Mo ◽  
Micheale Yihdego Gebreyohanes ◽  
Kaiyun Wang ◽  
Junyong Wang ◽  
...  
Keyword(s):  
Stress State ◽  
High Speed ◽  
Dynamic Properties ◽  
High Stress ◽  
Rigid Bodies ◽  
Response Analysis ◽  
Brake Disc ◽  
Dynamics Model ◽  
Coupled Dynamics ◽  
Brake Discs

To study the vibration characteristics and stress state of brake discs during vehicle operations, a spatial trailer car-track coupled dynamics model was developed with the consideration of flexible brake disc. In the model, the components of a trailer car are considered as rigid bodies. Flexible models of the brake disc and wheelset were established using the finite element method. The trailer car-track coupled dynamics model is validated using experimental test results. The effects of wheelset flexible deformation on the dynamic properties of brake discs were investigated with the excitations of track irregularity and wheel flats. Furthermore, the brake disc was systematically evaluated and discussed under the condition of wheel flats in the coupled dynamics system. The results indicate that compared to rigid wheelsets with wheel flats, flexible wheelsets can cause the brake disc to vibrate more severely with higher stress. The severe vibration and high stress state of the brake disc could cause it to crack in the region near the bolts. The established dynamics model can be further developed and employed to assess the dynamics of the brake systems of high-speed trains.

scholarly journals RESEARCH ON MATERIAL FLOW-STRESS BEHAVIOR AND THE DIE-FORGING PROCESS FOR FORGED-STEEL BRAKE DISCS FOR HIGH-SPEED TRAINS

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Zhenhong Li ◽  
Chenxing Zhang ◽  
Chenyu Wang ◽  
Yingna Huang
Keyword(s):  
Flow Stress ◽  
Process Parameters ◽  
High Speed ◽  
Brake Disc ◽  
Test Machine ◽  
Forming Process ◽  
Finite Element Software ◽  
Die Forging ◽  
Brake Discs ◽  
High Speed Trains

Due to the large size and complicated features, the brake discs of high-speed trains are difficult to forge, so a reasonable design of the process and the die parameter are prerequisites for successful forming. The flow stress of 23CrNiMoV, a forged-steel brake disc material for high-speed trains, was investigated by a uniaxial compression experiment on a Gleeble 1500 test machine. Based on the obtained flow-stress data, a series of numerical simulation analyses of the die forging of high-speed-train brake discs were carried out by using finite-element software. The effects of forging temperature, flash groove parameters and forming speed on the flow filling, forming load and temperature change of metal during die forging were studied. The simulation results were optimized and better process parameters were obtained. Based on the obtained process parameters, the simulation of the forming process was completed and a better forming quality was obtained.

scholarly journals Simulation Analysis and Verification of Temperature and Stress of Wheel-Mounted Brake Disc of a High-Speed Train

2020 ◽  
Author(s):  
Junsheng Qu ◽  
Wenjing Wang ◽  
Ziyu Dong
Keyword(s):  
High Speed ◽  
Plane Deformation ◽  
Tensile Load ◽  
Middle Part ◽  
Bolted Joints ◽  
Bench Test ◽  
Brake Disc ◽  
Mechanical Coupling ◽  
Brake Discs ◽  
Braking Process

Abstract During the braking process, a large amount of heat energy is generated at the friction surfaces between the brake disc and pads and rapidly dissipates into the disc volume. In this paper, a three-dimensional thermo-mechanical coupling model of high-speed wheel-mounted brake discs containing bolted joints and contact relationships is established. The direct coupling method is used to analyse the temperature and stress of the brake discs during an emergency braking event with an initial speed of 300 km/h. A full-scale bench test is also conducted to monitor the temperatures of the friction ring and bolted joints. The simulation result shows that the surface temperature of the friction ring reaches its peak value of 413.7°C after 102 s of braking, which agrees well with the bench test result. The maximum alternating thermal stress occurs in the bolt hole where the maximum circumferential compressive stress is -658 MPa and the maximum circumferential tensile stress is 134 MPa. During the braking process, the out-of-plane deformation of the middle part of the friction ring is larger than that of the edge, which increases the axial tensile load of the connecting bolt. This work provides support for the design of brake discs and connecting bolts.

scholarly journals A Study on Depth Sizing for Surface Cracks in KTX Brake Disc Using Rayleigh Wave

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Yun-Taek Yeom ◽  
Min-Soo Kim ◽  
Hak-Joon Kim ◽  
Sung-Jin Song ◽  
Ho-Yong Lee ◽  
...  
Keyword(s):  
Rayleigh Wave ◽  
Public Transportation ◽  
High Speed ◽  
Inspection System ◽  
Brake Disc ◽  
High Speed Railway ◽  
Brake Discs ◽  
Safety And Reliability ◽  
Railway System ◽  
Length Width

Korea Train eXpress (KTX), high-speed railway system, provides an important platform for public transportation and connects major metropolitans in Korea. KTX aiming towards next-generation transportation system has plans to increase the operation times. However, with increasing operation times, safety and reliability of the railways especially inspection of brakes systems becomes important. Therefore, in this study, a KTX brake disc inspection system using the Rayleigh wave is developed to characterize the cracks in the discs. The performance of the inspection system is evaluated on the KTX brake discs specimen having fabricated cracks as well as natural cracks. The result shows that the proposed algorithm successfully characterizes the crack types and estimated the length, width, depths and gap between cracks with good accuracy.

Power Consumption Analysis of High-Speed Train’s Brake Discs

2013 ◽  
Vol 765-767 ◽  
pp. 120-124
Author(s):  
Xiao Yu Zhu ◽  
Jian Yong Zuo
Keyword(s):  
Power Consumption ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Brake Disc ◽  
High Speed Train ◽  
Air Inlet ◽  
Resistance Torque ◽  
Brake Discs ◽  
Rotational Parts ◽  
Traction Power

Apart from the aerodynamic drag produced by transitional motion of high-speed train, the rotational parts of the train, especially the ventilated discs mounted on axles, would also cause resistance torques due to air pumping effect, which consume traction power. In this paper the train running process is divided into traction, uniform running and braking three phases, then the power consumed by the brake discs as well as the proportion of which in total traction or braking power during the three periods is calculated based on kinetic energy theorem. The results indicate that, during traction and uniform running period, the power consumption of brake discs shares 2.84% and 12.87% of total traction power, and in brake stage, the proportion is 0.78%. What is more, in the uniform running phase, the proportion of brake discs power consumption caused by resistance torque can reach to 7.68%. If the air inlet of brake disc is blocked during traction and uniform running period to weaken air pumping effect, the useless power consumption can be effectively reduced and the traction efficiency can be improved.

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