Technology Digests / Measuring Wheel Impact Force through the Bearing Adapter

TD23-014

September 18, 2023
Authors
  • Matthew Witte
  • Yuqing Zeng
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Key Findings

  • Force measurement through the bearing adapter is not sufficient to accurately measure wheel/rail impact force.
  • Wheel impact load transmitted to the bearing adapter is substantially attenuated at input frequencies above just a few hertz (Hz).
  • Mass, suspension characteristics, and wheel defect characteristics affect force transmissibility.
  • No single transfer function is sufficient to correct the transmissibility of the impact load through the wheel/bearing/suspension system.

Measuring Wheel Impact Force through the Bearing Adapter

MxV Rail investigated the transmissibility of wheel impact force through the bearing adapter in rail vehicles. The purpose of this study, a part of the Association of American Railroads’ (AAR) Strategic Research Initiatives (SRI) program, was to determine the efficacy of using on-board measurement of wheel impact force to validate wayside wheel impact load detectors. A simplified 4-degree-of-freedom (4DOF) model was used to investigate the frequency-dependence of force transmissibility through the suspension.   BACKGROUND  A wheel impact load detection (WILD) system is a wayside-condition monitoring method by which high impact load wheels (HIWs) are detected, evaluated, and indicated for removal. Wheelset replacement is the single highest interchange maintenance expense for North American freight railroads. Therefore, consistent indication is necessary for fair and objective cost sharing. Currently, all AAR-approved WILDs are validated according to AAR Standard S-6101,1 using a static calibration method based on work conducted in 1993.2 As a result, WILD…