Control of Internal Mechanical Stress in Rails Using the Acoustoelastic Effect

Abstract

AbstractThe method and technique permitting the time parameters of the introduced ultrasonic (US) waves to determine the longitudinal stresses in the rails using the acoustoelastic effect have been considered. A new scheme of longitudinal mechanical stress control in the rails with the use of longitudinal (L) and transformed (LT) waves has been proposed. For this purpose, two piezoelectric transducers with an angle of input equal to \(18^\circ\), operating in a mode of radiation and reception, were mounted on a 200 mm long piece of rail P65. It is shown that when transformed ultrasonic waves are used, compressive stresses are controlled. Experimental and computational dependencies of compressive stresses on load, which were obtained by acoustic and strain-measuring and computational methods, are given. The thermal tests of the rail section with the use of acoustoelastic effect have been carried out. Its heating with hot air was carried out with the help of construction hairdryer. At the same time, determination of propagation times of longitudinal and transverse waves was carried out by “Akust-1” system, temperature of rail heating was measured by rail thermometer of IT5-p/p-rail type with the limit of allowable error of measurement not more than ±1 °C. The developed acoustic method of control based on the effect of acoustoelastic makes it possible to determine mechanical stresses in rails with an error not exceeding 10%, which is acceptable for its practical application on the railroad.KeywordsRailContinuous welded railUltrasoundAcoustoelastic effectMechanical stressesTemperatureHeating