An investigation into the constitutive relation of corrugated metro rail material based on nano-indentation experiment and inverse analysis

To establish the constitutive relation of corrugated rail material, rail corrugation was reproduced. The material mechanical properties of corrugation peaks and troughs were obtained by experiment. A set of dimensionless functions was proposed for the elastic modulus, hardness and yield stress at arbitrary depth of corrugation peaks and troughs. By combining the finite element model and dimensional functions, the constitutive relations were obtained at different vertical and lateral positions of corrugation. The closer the material is to the rail surface, the larger the mechanical property values. The elastic modulus and hardness of corrugated rail material at the trough surface are higher than those at the peak, while the yield stress at the peak surface is higher than the trough.