Analysis of Hot Spots Evolution on Brake Disc Using High-Speed Infrared Camera

2009 ◽  
Vol 417-418 ◽  
pp. 317-320 ◽  
Author(s):  
Jeong Guk Kim ◽  
Sung Tae Kwon ◽  
Sung Cheol Yoon
Keyword(s):  
Hot Spots ◽  
High Speed ◽  
Hot Spot ◽  
Degradation Mechanism ◽  
Low Frequency ◽  
Infrared Camera ◽  
Material Design ◽  
Brake Disc ◽  
Ir Camera ◽  
Thermal Phenomenon

The hot spot generation has been considered as the main degradation mechanism in railway brake disc. Therefore, the understanding of hot spots, also called hot judder, which is undesirable low frequency vibrations developed by non-uniform contact area between brake pad material and brake disc, is important for a better understanding of material design as well as enhancement of materials properties in railway brake disc. Also, infrared (IR) thermography is a powerful NDE technique for the characterization of thermal phenomenon in engineering components and/or systems including engineering materials. The high-speed IR camera provides the measurement of temperature change during brake operation as well as the images of temperature contour on the brake disc surface. In this investigation, damage evolution due to generation of hot spots on railway brake disc was investigated using the infrared thermography method. Moreover, based on obtained thermographic images of hot spots, the hot spots and thermal damage of railway brake disc during braking operation were qualitatively analyzed.

Infrared Thermographic Analysis of Railway Brake Disc during Braking

2011 ◽  
Vol 488-489 ◽  
pp. 597-600 ◽  
Author(s):  
Jeong Guk Kim ◽  
Sung Tae Kwon ◽  
Sung Cheol Yoon ◽  
Byeong Choon Goo
Keyword(s):  
Hot Spots ◽  
High Speed ◽  
Hot Spot ◽  
Degradation Mechanism ◽  
Infrared Camera ◽  
Brake Disc ◽  
Ir Camera ◽  
Train Speed ◽  
Thermographic Analysis ◽  
Temperature Contour

The temperature monitoring on the surface of the railway brake disc was performed using high-speed infrared (IR) camera. The railway brake disc was developed for disc braking of maximum train speed of 180 km/h. The braking tests were conducted with a full scale dynamometer, and a high-speed infrared camera was employed to monitor temperature evolution on the brake disc during braking operation. The high-speed IR camera provides the measurement of temperature change during braking as well as the images of temperature contour on the brake disc surface. In general, the hot spot generation has been considered the main degradation mechanism in railway brake disc. In this investigation, damage evolution due to generation of hot spots on railway brake disc was investigated using the infrared thermography method.

Thermographic Investigation of Hot Spots in Railway Brake Discs

2008 ◽  
Vol 385-387 ◽  
pp. 669-672 ◽  
Author(s):  
Jeong Guk Kim ◽  
Byeong Choon Goo ◽  
Sung Cheol Yoon ◽  
Sung Tae Kwon
Keyword(s):  
Hot Spots ◽  
High Speed ◽  
Hot Spot ◽  
Infrared Camera ◽  
In Situ Monitoring ◽  
Brake Disc ◽  
Brake Discs ◽  
Thermographic Investigation ◽  
Experimental And Theoretical Studies

Damage evolution due to generation of hot spots on railway brake disc was investigated using the infrared thermography method. A brake disc with gray cast iron, which is currently used in Korea, was employed for this investigation. A high-speed infrared camera was used to measure the surface temperature of brake disc as well as for in-situ monitoring of hot spot evolution. From the thermographic images, the observed hot spots and thermal damage of railway brake disc during braking operation were qualitatively analyzed. Moreover, in this investigation, the previous experimental and theoretical studies on hot spots phenomenon were reviewed, and the current experimental results were introduced and compared with theoretical prediction.

scholarly journals Non-Destructive Characterization of Railway Materials and Components with Infrared Thermography Technique

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4077 ◽  
Author(s):  
Jeongguk Kim
Keyword(s):  
Infrared Thermography ◽  
Thermal Imaging ◽  
High Speed ◽  
Hot Spot ◽  
Imaging Techniques ◽  
Brake Disc ◽  
Ir Thermography ◽  
Contact Mode ◽  
Non Destructive Evaluation ◽  
Non Destructive

Infrared (IR) thermography technology is one of the leading non-destructive evaluation (NDE) techniques based on infrared detection. Infrared thermography, in particular, has the advantage of not only being used in non-contact mode but also provides full images, real-time inspection, and relatively fast results. These advantages make it possible to perform thermal imaging analysis of railway materials and/or components, such as brake disc simulation, monitoring of abnormal heat generation, and monitoring of temperature changes, during mechanical tests. This study introduces the current state of research on railway materials and/or components using IR thermography technology. An attempt was made to characterize the deterioration of electrical equipment of diesel electric locomotives using infrared thermal imaging techniques. In addition, surface temperature monitoring was performed during tensile testing of railway steels using a high-speed infrared camera. Damage evolution due to the hot spot generation of railway brake discs was successfully monitored using high-speed IR cameras. In this paper, IR thermal imaging technology, used as a non-destructive evaluation analysis in the railway field, was introduced, and the results of recent research are presented.

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.

Local Hot Spots of Electric Water Pump Casing Over Various Pumping Loads

2020 ◽  
Author(s):  
Younghyeon Kim ◽  
Yoora Choi ◽  
Sangseok Yu
Keyword(s):  
Temperature Distribution ◽  
Joule Heating ◽  
Hot Spots ◽  
Cooling System ◽  
Hot Spot ◽  
Maximum Temperature ◽  
Water Pump ◽  
Ir Camera ◽  
Heat Rejection ◽  
Electric Water Pump

Abstract The cooling system of an electric vehicle adopts an electric water pump. Since the lifespan of the battery is very sensitive to a very narrow temperature band, the cooling system provides key solutions. The electric water pump is a core component of the cooling system which satisfies performance and durability criteria. Since, a local hot spot of motor casing results in the degradation of motor lifespan, it is necessary to design the motor casing for effective heat rejection. In this study, two different motor casing designs are applied to reject the joule heating of the motor efficiently. The temperature distribution of each casing is investigated with an IR camera. The IR camera was used to identify the local hot spot where the heat was most generated in the pump. Since the joule heating is proportional to pump power, it is necessary to understand the operating characteristics of the electric water pump. The experimental apparatus includes a water reservoir, a bypass valve, pressure and temperature sensors, DAQ, and IR camera. The operating temperature is ranged from atmospheric temperature to 50°C. When the pump is operated with 25°C coolant, each experiment takes 1 hour for the steady-state conditions and maximum temperature up to 55 °C. Three different pump performance are investigated with two different pump casing. The coolant temperature is also changed from 25 °C to 50 °C. As a result, the local hot spot is strongly dependent to pump load and it is mainly observed near the cable connector. Since temperature distribution on the casing surface is also affected by local hot spots, it is necessary to optimize heat rejection by extended surface.

FLAME FRONT DYNAMIC STUDIES BEFORE THE ONSET OF DETONATION IN DILUTED STOICHIOMETRIC ACETYLENE-OXYGEN MIXTURES

2020 ◽  
Author(s):  
Ya. A. Baranyshyn ◽  
◽  
P. N. Krivosheyev ◽  
O. G. Penyazkov ◽  
K. L. Sevrouk ◽  
...  
Keyword(s):  
Shock Wave ◽  
Flame Front ◽  
Hot Spots ◽  
High Speed ◽  
Spatial Configuration ◽  
Hot Spot ◽  
Video Recording ◽  
Pressure Sensors ◽  
Front Propagation ◽  
Transition To Detonation

The results of experimental research of deflagration-to-detonation transition (DDT) in stoichiometric mixtures of acetylene-oxygen diluted by 70% argon or 60% nitrogen in round smooth tube with diameter of 0.04 m in the mode of low-energy initiation of combustion by a spark discharge (0.8 mJ) are presented. Simultaneous registration of shock wave propagation by high-frequency pressure sensors and the reaction front propagation by ionization sensors allowed us to obtain the quantitative data on the dynamics of the formed shock wave, local velocity of the flame front, and its spatial configuration (relative to the walls of the tube) and to determine the length of the flame and the distance between the shock wave and the flame front in the process of its acceleration. Two typical stages of flame acceleration were observed in experiments. At flame velocities less than the sound velocity of the products, the spatial configuration of the flame front was very unstable and its strong transverse oscillations were recorded. With further increase in the speed, the spatial configuration of the flame front was stabilized before transition to detonation. The high-speed video recording of the glow at the DDT made it possible to register the appearance of hot spots and to determine their position relative to the tube walls and the front flame front. It is established that after the flame front attains a speed of an order of sound speed in the products, near a tube wall between a shock wave and a flame front, there is a hot spot from which the detonation wave develops. In the mixture diluted with argon, several hot spots were often observed simultaneously. In the mixture diluted with nitrogen, weak initiation modes were observed, in which the emergence of the hot spot did not lead to the development of detonation over long distances (more than a meter). In a mixture diluted with argon, the occurrence of a hot spot always led to detonation.

A Study of Judder Vibration in Automotive Disk Brakes

2006 ◽  
Vol 326-328 ◽  
pp. 1301-1304 ◽  
Author(s):  
Ho Joon Cho ◽  
Chong Du Cho ◽  
Myoung Gu Kim ◽  
Ju Wong Maeng ◽  
Sang Kyo Lee
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Infrared Camera ◽  
Mode Frequency ◽  
Mode Shapes ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Brake Disk ◽  
Disk Brake ◽  
The Relationship

In this experimental paper, the judder vibration of automotive disk brake was analyzed by the finite element method and compared with experimental results. The relationship between specific modes of disk and pad, and hot spot was investigated. Characteristics of the judder vibration were measured by using the chassis-dynamo and hot spots were photographed by highspeed infrared camera. Vibration modes of the brake disk and pad were measured and an specific relationship between mode shapes and hot spots was found. Results show that the judder vibration occurred due to the frequency modulation of the specific mode frequency of disk brake due to the non-linearity phenomenon. This relationship was examined by the frequency analysis of the judder vibration.

scholarly journals Simplified three-dimensional finite element hot-spotting modelling of a pin-mounted vented brake disc: an investigation of hot-spotting determinants

2017 ◽  
Vol 232 (7) ◽  
pp. 877-895
Author(s):  
Jinghan Tang ◽  
David Bryant ◽  
Hongsheng Qi ◽  
Ben Whiteside ◽  
Max Babenko
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Heat Generation ◽  
Hot Spots ◽  
Hot Spot ◽  
Three Dimensional ◽  
Element Model ◽  
High Energy ◽  
Brake Disc ◽  
Brake Pad

Hot spotting is a thermal localisation phenomenon in which multiple hot regions form on a brake disc surface during high-energy and/or high-speed braking events. As an undesired problem, hot spots can result in high-order brake judder, an audible droning noise and thermal cracking. This paper presents a finite element model for hot-spot modelling which introduces the classical axisymmetric assumptions to the brake pad in three dimensions by scaling the material properties combined with a subroutine to simulate the heat generation instead of modelling the rotation of the brake pad. The results from the initial feasibility models showed significant improvement in the computing efficiency with acceptable accuracy when compared with a traditional finite element model without such simplifications. This method was then applied to three-dimensional simulations of hot spotting on a realistic ventilated brake disc–pad pair, and the results showed good correlation with the experiments. In order to improve the understanding of the hot-spotting mechanism, parametric studies were performed including the effects of a solid-disc geometry and a ventilated-disc geometry, the rotational speed and energy, the pins, the disc run-out and the brake pad length. Based on the analysis of the results, it was identified that the vents and the pins affected the hot-spot distribution. The speed was shown to be more important in the hot-spot generation time and the hot-spot distribution than either the pressure or the total energy input was. The brake disc run-out was shown to affect the magnitude of both the hot-spot temperature and the hot-spot height because of the non-linear relationship between the local deformation, the contact pressure and the heat generation. Finally, increasing the brake pad length generated fewer hot spots, but the temperature of each hot spot increased.

scholarly journals High-Speed Study of Drop-Weight Impact Ignition of PBX 9501 Using Infrared Thermography

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Emily M. Hunt ◽  
Steve Malcolm ◽  
Matt Jackson
Keyword(s):  
Hot Spots ◽  
High Speed ◽  
Reaction Rate ◽  
Hot Spot ◽  
Exothermic Reaction ◽  
Strong Temperature Dependence ◽  
Explosive Materials ◽  
Weight Impact ◽  
Transfer Mechanisms ◽  
Ignition Site

Reaction in explosive materials does not occur as a result of homogenous heating of the sample, but rather from a localized region of high temperature called a hot spot. Observation of hot spot development is critical in understanding the heat transfer mechanisms occurring during reaction. Due to the strong temperature dependence of explosives, the overall reaction rate is dominated physically by these hot spots. Once formed, these hot spots either fail to react chemically due to thermal diffusion or react exothermically thus creating an ignition site in the solid explosive. The slightest difference of physical properties can change the positioning of hot spot development, creating an argument that the differences in material properties influence the formation of hot spots, which produce an exothermic reaction.

Spatial Hotspot Analysis of Bucharest’s Urban Heat Island (UHI) Using Modis Data

2018 ◽  
Vol 18 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Georgiana Grigoraș ◽  
Bogdan Urițescu
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Hot Spots ◽  
Land Surface ◽  
Hot Spot ◽  
Monitoring Network ◽  
Residential Areas ◽  
Hotspot Analysis ◽  
The City

Abstract The aim of the study is to find the relationship between the land surface temperature and air temperature and to determine the hot spots in the urban area of Bucharest, the capital of Romania. The analysis was based on images from both moderate-resolution imaging spectroradiometer (MODIS), located on both Terra and Aqua platforms, as well as on data recorded by the four automatic weather stations existing in the endowment of The National Air Quality Monitoring Network, from the summer of 2017. Correlation coefficients between land surface temperature and air temperature were higher at night (0.8-0.87) and slightly lower during the day (0.71-0.77). After the validation of satellite data with in-situ temperature measurements, the hot spots in the metropolitan area of Bucharest were identified using Getis-Ord spatial statistics analysis. It has been achieved that the “very hot” areas are grouped in the center of the city and along the main traffic streets and dense residential areas. During the day the "very hot spots” represent 33.2% of the city's surface, and during the night 31.6%. The area where the mentioned spots persist, falls into the "very hot spot" category both day and night, it represents 27.1% of the city’s surface and it is mainly represented by the city center.

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