Framework for Wheel Life Model – Phase I

Researchers developed a model to predict the life of a freight railroad car wheel due to rolling contact fatigue, crack initiation and growth leading to fracture. The Phase I effort includes a literature survey, an estimation of hoop residual stress from manufacturing process, and the effects of mechanical load – including traction and thermal load due to tread-braking on the initial residual stresses distribution in the wheel. An analysis shows how a severe braking event may completely eliminate the beneficial hoop residual stress in the rim of a wheel, which can otherwise delay crack initiation and growth. An approach to include the residual stress in the shakedown theory used to predict rolling contact fatigue is proposed to investigate crack initiation and growth.