On Constitutive Models for Ratcheting of a High Strength Rail Steel

Abstract

The ratcheting behaviour of a hypereutectoid high strength rail steel with carbon content of 0.85% was experimentally studied under both uniaxial and bi-axial cyclic loadings recently by the authors. To numerically simulate the multiaxial ratcheting behaviour of the rail steel, the Abaqus built-in Lemaitre-Chaboche model was applied first in current study. Following Abaqus documentation, the material data for the Lemaitre-Chaboche model were calibrated from the uniaxial loading test results. Comparing with experimental data, the Lemaitre-Chaboche model with the calibrated data provides overpredictions for the ratcheting responses of the rail steel under both uniaxial and bi-axial loadings. After that, a modified cyclic plasticity model with a coupling multiaxial parameter in the isotropic and kinematic hardening rules was applied for the material. The material data for this modified model were calibrated from both uniaxial and bi-axial loading tests. Comparison between the simulated results and the experimental data show that this modified cyclic plasticity model has the capacity to simulate both uniaxial and multiaxial ratcheting behaviour of the hypereutectoid rail steel with an acceptable accuracy.