Southwest Research Institute

Transportation Technology Center, Inc.

Douglas R Earnest

Adam C Cobb

Sergey A Vinogradov

Keith Alan Bartels

Clinton Thwing

Jonathan Bartlett

Richard Paul Reiff

Greg A Bustamante

Xin Chen

Gopichand Katragadda

Gregory Anthony Garcia

A method of in situ measurement of an acoustoelastic constant (L) of a railway rail, using an ultrasonic wedge sensor to measure a stress-free (unloaded) time-of-flight (t) in the vertical direction of the rail. Next, a vertical load of known load value is applied to the rail. While the vertical load is applied, the ultrasonic wedge sensor is used to measure a stressed time-of-flight value. The difference between the stress-free and the stressed time-of-flight is calculated to obtain a time-of-flight difference value (Δt). Based on the load value, the stress-free time-of-flight value, and the time-of-flight difference value, the acoustoelastic constant, L, may be calculated. The wedge sensor may be further used to measure the (stressed) horizontal time of flight, and a time-of-flight difference value in the horizontal direction may be used to measure longitudinal stress.

Reference-free load-modulated longitudinal rail stress measurement using ultrasonic LCR waves

A guided wave probe for use in guided wave testing of plate structures. The probe comprises a cup having a flat or nearly flat bottom, and a guided wave sensor, such as a magnetostrictive sensor, placed in the bottom of the cup. The sensor and/or cup are coupled to the plate structure, such that ultrasonic energy from the sensor is transmitted to the cup and the plate surface. The sensor is incrementally rotated in the cup, and sensor data is acquired at each incremental position.

Omni-directional guided wave testing of plate structures using probe having rotating guided wave sensor

A method and system for detecting transverse cracks beneath horizontal cracks in the rail way track. As a transporter moves over rail, a saturation magnetic field is generated into and across the rail head using a toroidal-shaped DC saturation magnet located a predetermined distance above the rail head. Any transverse cracks in the rail head are detected with a low frequency eddy current probe mounted centrally between the opposing pole ends of the DC magnet and over the rail head. A force is applied to the low frequency eddy current probe to hold the probe towards the rail head as the transporter moves on the rail so as to follow the wear pattern of the rail head and to minimize lift-off. A second sensor is used to sense the presence of non-relevant indications that falsely indicate possible transverse cracks by the low frequency eddy current probe.

Transverse crack detection in rail head using low frequency eddy currents

Growing community of inventors

San Antonio, TX, United States of America

Douglas R Earnest