Transient Impact Behavior Analysis of Rail Broken Gap on High-Speed Continuous Welded Rail

The rail of seamless track may break and form a broken gap at the weld and its heat affected zone under temperature force. In order to study the influence of rail broken gap on train operation, the wheel-rail contact force characteristics and the high-frequency dynamic response of the material is analyzed. First, the ANSYS/LSDYNA three-dimensional wheel-rail transient rolling contact finite element model was established; then, according to the time-domain response of wheel-rail forces at different speeds, the appropriate calculation conditions are selected, and the safety issue in the case of the wheel crossing the broken gap is analyzed by calculating the wheel-rail contact force and the high-frequency dynamic response of the material; finally, when the wheel crosses the gap, the frequency-domain distribution of the wheel-rail force is obtained by wavelet transform. The results show that the peak value of the high-frequency impact force decreases at first and then increases as the length of the rail broken gap increases. The length of the broken gap at the turning point is inversely correlated to the train speed; when the wheel passes through the gap, the maximum shear stress of the rail exceeds the material failure limit, which may cause the brittle fracture of the rail material; there are two special frequency components in the time-frequency diagram of the wheel-rail force, which respectively correspond to the high-frequency impact load (about 1 500 Hz) and secondary impact load (about 450 Hz); the gap length has little effect on the frequency-domain distribution of the wheel-rail force.