Estimation of the residual stresses in rails using electromagnetic–acoustic introduction–reception of waves

Strain Stress Model of the Rail with Crack in its Head and Estimation of its Operational Lifetime

“…Modern Problems in Materials Processing, Manufacturing, Testing and Quality Assurance II According to the results of modeling tensile stresses in the rail foot, the critical value of 250 MPa is exceeded, when the weighted average stress value is below |-52 MPa|. The modeling results have been confirmed by experimental studies of the internal stresses in rails [13].…”

“…Acoustoelasticity. Experimental nondestructive estimation of the stressed-strained state of the rail was made using the acoustoelasticity method [12,13], which is based in the case of the one-axis stress state, on measuring the velocity difference of two transverse acoustic waves with mutually perpendicular polarizations. The Input-reception of waves is made by the electromagnetic-acoustic (EMA) method.…”

“…The texture factor was taken into account when measuring the fragment of a rail that had undergone heat treatment by annealing with the release of internal stresses. The resultant oscillograms were processed in the PRINTS software environment [12,13,16].…”

“…2; the main technical features are listed in Table 3. The level of weighted-mean stresses, obtained by the method of acoustoelasticity using the SEMA structuroscope with insonification on the rail-head side, for a rail with the critical level of residual stresses is estimated at -77 MPa with an error of 3 MPa [12,13,16]. Therefore, the According to Table 5, in the area of the sharp crack, the area of sharp crack stresses is several times more, than that of the yield stress (for rail hardening steel σ0.2=800 MPa), so it will cause a 182…”

“…The reason of the thermal stresses is the actual temperature fluctuation as compared to the installation temperature. Changing the temperature by 1°C causes the increase of stresses by +2.5 MPa [12][13][14]. Results of sum stresses and element stresses modeling in case of different ΔT are shown in Table 2, where ΔT is the difference between the actual temperature and the installation temperature, °C.…”