Technical Reports

Advanced Railroad Wheel/Rail Interaction Force Measurement

  • 07
  • Nov
  • 2000
AUTHOR: Jeffery Everson, Susan MacPherson, Terrence Barnes, Wayne Hill
SUBJECT: Track/Train Interactions
KEYWORDS: Foundation Disk, Power System, MEMS Sensors
ABSTRACT: The Phase I research into the development of a novel, cost effective and efficient wheel/rail interaction force measurement system demonstrated the ability to use silicon strain gauges, fabricated with MEMS manufacturing techniques, to measure the types of forces seen in car wheels. Silicon strain gauges, which operate based on their piezoelectric properties, were evaluated in the laboratory to compare their functionality to conventional resistive strain gauges. A design for the overall system concept is presented, including the foundation disk: the component that will hold all of the electronics and will be bonded to the wheel. Extensive epoxy evaluations, consisting of coupon load and fatigue tests, were performed in order to choose the best epoxy for this application. The program also demonstrated the ability to transmit data using RF data transmission hardware. A prototype transmission system contained within an electronics system a few inches in diameter was used to transmit data from the silicon gauges to a receiver attached to a data collection system. Evaluations proved that data could be reasonably transmitted by the prototype system over distances up to about 10 feet. The application of state-space analysis to the problem of system calibration is presented. The present methodology for measuring wheel/rail interaction forces involves extensive finite element modeling and precise gauge placement. The state space approach for calibration provides a simpler and quicker calibration methodology that will not require the precise gauge placement.