Technical Reports

Ultrasonic Pulse Propagation in the Cold-Worked Layer of Railroad Rail

  • 01
  • Jan
  • 1978
AUTHOR: University of Oklahoma, School of Aerospace, Mechanical, and Nuclear Engineering
OFFICE: RPD
REPORT NUMBER: FRA/ORD-77/09.2
SUBJECT: Rail and Infrastructure Integrity, Evaluation
KEYWORDS: Wave Propagation, Layered Media Wave Propagation, Texture, Rail Nondestructive Inspection
ABSTRACT: Ultrasonic pulses propagating along the rolling surface of used railroad rail were observed to have two distinct arrivals. One arrival corresponded to the expected Rayleigh wave. The other, travelling just ahead of the Rayleigh wave, could not be identified as either a pure shear or dilatational wave. An analysis of the material properties in the rail head showed some significant differences to exist between the cold-worked layer on top of the rail and the underlying structure. The observed condition of a low-velocity layer over a high-velocity substructure was found to satisfy the requirements for the propagation of the M2 (Sezawa) shear wave mode. Experimental data and solutions to the governing wave equation showed that the early arrival was the M2 mode. The cause of the shear wave velocity reduction in the cold-worked zone was investigated. The results of these investigations showed that a material texture having the (531) crystallographic plane parallel to the rolling plane and the [112] crystallographic direction parallel to the rail axis was the most probable cause of the velocity reduction.
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