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Residual stresses in railroad wheel rims significantly affect the wheel failure life; therefore, it is important to consider residual stresses for wheel failure analysis. In this paper, an advanced computational methodology is developed to estimate residual stresses developed during both the manufacturing process and under service conditions. To estimate the residual stresses in the wheel, three-dimensional decoupled thermal-structural analyses are performed. To simulate the manufacturing process, thermal analysis is performed with convection boundary conditions on the wheel surfaces. The temperature distributions obtained from this thermal analysis are input as loads for structural analysis. The results represent as-manufactured residual stresses. To simulate the thermal brake loading under service conditions, thermal analysis is performed using a heat flux boundary condition on the tread surface. Structural analysis is performed, including the estimated as-manufactured residual stress as initial stress, and using the temperature distributions obtained from thermal analysis of the on-tread braking. The resultant stresses represent the complex combination of residual stresses developed during both the manufacturing process and on-tread braking. The computed results are compared with the experimental data obtained at TTCI and the values reported in the literature.

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Vertical split rim cracking, rapid unstable propagation of a sub-surface crack parallel to the front rim face, is one of the dominant railroad wheel failure types observed in North America. Wheel impact load is believed to be a trigger for this unstable crack growth. This rapid crack growth rate depends on several factors, such as wheel geometry (wheel diameter and rim thickness), load magnitude, load location, residual stresses in the rim, worn tread profile, and material defects in the rim (size, shape, location, and orientation). This paper investigates the effect of these parameters on vertical split rim cracking, using finite element analysis and fracture mechanics. Vertical split rim cracking is modeled using a three-dimensional, multiresolution, elastic-plastic finite element analysis. Material defects are modeled as mathematically sharp cracks. Wheel impacts are simulated by applying a high axle load on the tread surface. The residual stress and wheel wear effects are also included in modeling vertical split rim cracking.