Analytical model coefficient of friction (COF ) of rail disc brake on the basis of multi-phase stationary tests

Sawczuk, Wojciech

doi:10.17531/ein.2018.1.8

Cited by 16 publications

(6 citation statements)

References 31 publications

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“…First, bench tests were carried out on railway brake discs. This research was conducted using the same methodology as in [ 29 , 30 ]. The research was carried out in at Łukasiewicz Research Network IPS TABOR in Poznan, Poland.…”

Section: Methodology Of Testing Surface Cracksmentioning

confidence: 99%

Modeling the Depth of Surface Cracks in Brake Disc

et al. 2021

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The article presents the state of knowledge and research in the field of surface cracks occurring in disc braking systems of rail and car vehicles. The craze formed during the operation of vehicles is particularly dangerous and leads to breaking the disc into several pieces. It may lead to a loss of braking force and damage to the entire disc brake caliper. The main aim of the research is to identify surface cracks in brake discs made of cast iron and use experimental methods to estimate their depth. Research were conducted on the disc braking system developed by the authors. In examining the location and depth of cracks, the penetration method, ultrasound, as well as a special probe were used. This device measures the crack depth based on the electrical resistance between two points on the surface of the metallic object. The tests showed that the first microcracks on the brake discs appeared after 309 braking tests on the test stand. In addition, it was observed that the surface cracks length of the disc increased linearly to depth until they reached about 11.5–12 mm with corresponded to crack lengths in the range of 65–70 mm. However, determination of the regression functions presented in the article allows to estimate the depth of surface cracks up to 70 mm long on cast iron brake discs by measuring their length.

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Section: Methodology Of Testing Surface Cracksmentioning

confidence: 99%

Modeling the Depth of Surface Cracks in Brake Disc

et al. 2021

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“…However, validation of the model on the new and worn disc gave a relative percentage error of 4 and 7%. It should be noted that the research and modeling of the average coefficient of friction µ m were also presented in [ 56 ]. This article takes into account another variable from the group of design parameters; that is, disc perforation in the form of holes on the friction surface and its impact on frictional characteristics.…”

Section: Verification and Validation Of The Model Of The Variability Of The Friction Coefficientmentioning

confidence: 99%

Modeling the Average and Instantaneous Friction Coefficient of a Disc Brake on the Basis of Bench Tests

Sawczuk

Cañás

Ulbrich³

et al. 2021

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This article presents the results of tests conducted on the average and instantaneous friction coefficients of railway vehicle disc brakes. The tests were carried out independently of various states of wear on the friction linings and the brake disc. The requirements of the International Union of Railways (UIC) regarding the approval of brake linings for use were taken into account. Based on many years of research using a brake bench to test railway disc brakes, the authors developed multiple regression models for the average friction coefficient and fluctuations (tolerances) in the instantaneous friction coefficient and achieved 870 results. The models proposed three types of variables: the input braking parameters (speed, pressure, and mass to be braked), operational parameters (the wear on the friction linings and the brake disc), and design parameters (perforations in the form of holes on the disc surface). The above two models were validated on the basis of 384 brakes, and in subsequent stages a further evaluation was performed. The coefficients were determined to be, respectively, 0.99 for the model of the average friction coefficient and 0.71 for the model of tolerance (fluctuations) of the instantaneous friction coefficient.

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“…The authors proposed a mathematical model based on the results of temperature distribution in rolling contact obtained with the use of the finite element method during full slip in order to calculate the heat partition factor of the interacting bodies on a wheel and rail contact test rig, identical as the numerical model. Sawczuk, 7 in turn, used an infrared camera to determine temperature distribution when developing an analytical model of the variability of the coefficient of friction (COF) of the rail disc brake. What is also worth noting is the measurement system of lateral displacement of a wheelset on track developed by Assets4Rail.…”

Section: Introductionmentioning

confidence: 99%

Thermal imaging of the wheel-rail interface

Firlik

Staśkiewicz

Słowiński

2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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The paper presents the use of a new method of imaging of the wheel-rail interface wear adopting thermal imaging techniques. Based on the heat generated at the point of contact, coming from the friction and strain of the mating materials, it is possible to identify the type and location of the wheel-rail interface. This work presents the usability of the method with reference to the typical conditions of operation of light rail vehicles (small-radius curves – from 22 m, wheel diameter around 0.6 m, lower standard of track maintenance than in the case of regular railways, use of shallow-grooved frogs, etc.). Thermal imaging presents a big potential in terms of monitoring the wheel-rail interaction and can also be used to identify flange climbing, rolling noise generation or longitudinal creepage during traction or braking.

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Analytical model coefficient of friction (COF ) of rail disc brake on the basis of multi-phase stationary tests

Cited by 16 publications

References 31 publications

Modeling the Depth of Surface Cracks in Brake Disc

Modeling the Depth of Surface Cracks in Brake Disc

Modeling the Average and Instantaneous Friction Coefficient of a Disc Brake on the Basis of Bench Tests

Thermal imaging of the wheel-rail interface

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