The Influence of Brake Shoes on the Temperatures of Wheels in Railroad Service

Wetenkamp, H.R.; Eck, Bradley; Rhine, P E

doi:10.1115/1.3183825

Cited by 5 publications

(1 citation statement)

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“…After strains are read from the strain gage rosette, the average and the approxirnate residual stresses in the principal coordinate system and the stress components in the sample coordinate system may be easily obtained on a personal computer using Equations (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) to (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) and a spreadsheet program such as Lotus l23°°.…”

Section: Principles Of Residual Stress Measurements By X-ray Diffractmentioning

confidence: 99%

Residual stress measurement in railroad car wheels

1993

NDT & E International

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A new failure criterion for discriminating good and bad (overheated) railroad car wheels is proposed. This criterion can replace the conventional "four inch" discoloration rule. The procedure for the new discrimination criterion is based on the fluctuations of the azimuthal residual stress in the tread of the wheel. This criterion is based on a maximum likelihood statistical analysis of data obtained from six different wheels as deterrnined by x-ray diffraction. Of these locations, the analysis showed the tread, and perhaps a critical point on the top of the flange, to be the most sensitive .to residual stress. The variance analysis showed that fluctuations in stress at the most sensitive location in the tread appeared to be related to the service history. The residual stresses showed an oscillatory pattem in the hoop direction around the wheels.Extension of the measurement technology to the use of magnetoelastic stress measurement is proposed. To evaluate the inaccuracy in stress data possible from a large sample with curved surface, corrections for a deliberate tilt of the plane of the x-ray diffractometer from the normal to the sample surface have been developed. Analysis of different misalignments are discussed. To validate our x-ray residual stress data, residual stresses were also measured by hole drilling. Excellent agreement between two techniques was found. Finally, stress variation with depth below surface was deterrnined by the hole drilling technique.

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Section: Principles Of Residual Stress Measurements By X-ray Diffractmentioning

confidence: 99%

Residual stress measurement in railroad car wheels

1993

NDT & E International

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Investigation of tribological properties of brake shoe materials — phosphorous cast irons with different graphite morphologies

Zhang

Chen

et al. 1993

Wear

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On the Replacement of Shoe-Wheel Brakes by Pad-Disk for Railroad Freight Cars

Romano¹,

Santos²,

Santos

2013

Journal of Thermal Science and Engineering Applications

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Most of railroad freight cars use brake shoes directly applied onto the wheels. This system causes wheel heating, which in turn gives rise to thermal stresses and loss of mechanical strength. An alternate solution is a system of brake disks and pads, which would not heat the wheels, like disk brakes. Because temperature is one major factor affecting braking performance, a study of the viability of replacing shoe brakes by disk brakes must evaluate and compare the heating of wheels and disks. The present work evaluates the heating of disk-pad systems when used for braking freight cars in the same conditions regularly applied to shoe-wheel brakes. In addition, stop distance for both systems are evaluated for regular speeds of freight railroads. Preliminary numerical simulations were done to choose the critical brake condition and to check whether the expected temperatures would exceed the temperature limits, damaging the friction materials and systems. Following that, real scale tests were conducted in critical braking conditions for both types of brake systems. Dynamometer tests were performed in real scale at the Railroad Laboratory of the State University of Campinas, Brazil. Results showed that, as far as system heating is concerned, there is nothing to prevent the replacement of the current system by a disk-pad system. Besides, the stop distance for both systems is also in the recommended range.

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The Influence of Brake Shoes on the Temperatures of Wheels in Railroad Service

Cited by 5 publications

References 0 publications

Residual stress measurement in railroad car wheels

Residual stress measurement in railroad car wheels

Investigation of tribological properties of brake shoe materials — phosphorous cast irons with different graphite morphologies

On the Replacement of Shoe-Wheel Brakes by Pad-Disk for Railroad Freight Cars

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