Abstract
To investigate the interaction mechanism between temperature gradients and material temperature dependency in wheel-rail contact behavior, a three-dimensional thermomechanical coupled finite element model was established. Heat flux density, normal/tangential loads, wheel-rail interfacial heat transfer boundary conditions, and surface convective heat transfer coefficients were applied to systematically examine temperature field evolution and its influence on stress-strain characteristics. The results indicated that: (1) Nonlinear temperature growth was observed in the contact patch, with radial temperature gradients significantly exceeding circumferential and axial gradients; (2) Temperature field heterogeneity was dominated by frictional heat source spatial distribution; (3) Temperature-dependent elastic modulus variations increased strain magnitudes by 64%–571%, while reduced friction coefficients induced differential evolution of circumferential/axial normal and shear strains; (4) Radial-circumferential shear strain reversal triggered shear instability. Stress field analysis revealed dominance of normal stresses and radial-circumferential shear stresses, with maximum stress offset ratios reaching 11.5% due to temperature gradient-driven strain redistribution. Yield strength and Poisson’s ratio were observed to inversely regulate stress spatial distributions. The coupled mechanism between thermal gradient effects and temperature-dependent material properties was clarified, providing theoretical support for optimizing wheel-rail thermomechanical performance and thermal damage assessment.
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