Contact Stress Analysis
Wheel/rail contact and the damage to both surfaces continue to preoccupy railway engineers. From wheel shelling to rail spalling, the causes and mitigation thereof are part of the services that ARRT provides. Understanding the loading into the track and the stresses they generate is the first step in identifying the root cause of the problem.
Thereafter, ARRT computes contact stresses and damage using the FE method or traditional Hertzian approach (available in numerous sources in the literature). The Hertzian approach provides an estimate of the size of the contact patch from which the contact and associated shear stress are computed. The contact patch is dependent on the magnitude of the vertical loads and the four radii of the contacting surfaces. As the loads or the radii varies, so do the contact and shear stresses. The shear stress in the contact patch is what causes the most damage to the rail material and is the cause of contact fatigue failure. ARRT has the experience and can help your railroad to resolve contact damage related problems.