Trend analysis of rail corrugation in metro lines considering friction memory and interface effects

In order to investigate the evolution trend of rail corrugation under the action of slip and interface effects, stick-slip vibration characteristics of a wheel-rail system in different line con- ditions have been analyzed in detail by establishing a complete three-dimensional coupling metro vehicle-track numerical model and considering the friction memory effect characteriz- ing the slip rate and state dependence as well as interface effect. The results show that on a straight line, the friction memory effect has less influence on the wheel-rail contact stick-slip characteristics, and the values and variation ranges of adhesion coefficients and creepages are relatively small, indicating that it is difficult for the wheel-rail system to have stick-slip vibration, which makes it less likely to form rail corrugation. On a curved line, the fluctua- tion amplitudes of the inside longitudinal stick-slip characteristics and the outside transverse stick-slip characteristics are relatively large, which illustrates that the inside wheel-rail sys- tem is more prone to stick-slip vibration in the longitudinal direction, while the outside wheel-rail system is more prone to stick-slip vibration in the transverse direction, thus lead- ing to different forms of rail corrugation. The friction memory effect reduces longitudinal and transverse creepages of both the inside and outside wheel-rail systems, demonstrating that the friction memory effect can moderate the relative wheel-rail slip and thus reduce the development rate of rail corrugation. The interface effect makes longitudinal and transverse adhesion coefficients of the wheel-rail system tend to homogenize and mostly decrease, while the corresponding creepages tend to increase. Although an increase in the creepage induces an enhanced interface slip, a smaller adhesion coefficient does not cause a significant change in the corrugation evolution. Friction memory and interface effects can cause the wheel-rail contact adhesion area ratio to increase, thus making the contact stick-slip distribution tend to homogenize, which is beneficial to reduce wear in the contact area and promote wear to homogenize.