A new feature for detecting defects in ultrasonic high-speed rail inspection

Abstract

In high-speed testing of railway rails using ultrasonic transducers, there are significant deviations of the carrier frequency of echo signals from the frequency of filling the probing pulses. They are caused by the Doppler Effect. Since inclined ultrasonic transducers have a certain width of the directional diagram, the Doppler frequency of the echo signal from any reflector in the rail has a deviation that reaches 14-30% of the average value of the Doppler shift. Analysis of this frequency modulation of received signals allows detecting possible defects in rails with high noise immunity.