Numerical modeling and determination of the stress-strain state of railway wheels with the presence of subsurface physical type stress concentrators

Abstract

Problem statement. The problem of establishing the stress-strain state of carriage wheels with the presence of subsurface inclusions is considered. Purpose. The purpose of this article is to build a methodology to establish dependence between the parameters of subsurface inclusions and the contact strength of railway wheels. Methodology. Based on modern models of the mechanics of a deforming solid of non-local (gradient) media, approaches to assessing the strength of structures and methods of mathematical modeling, the spatial distribution of the field of displacements, stresses and softening that occurs in the elements of carriage wheels under operational friction loads has been established. For the computer implementation of the task, the Python version of the free Fenics finite element analysis package was used. Findings. Conducted studies of this applied problem have shown that the presence of an inclusion reduces the size of the zone with increased strength characteristics; in addition, on the surface of the inclusion, the base metal, the level of stress increases, which leads to the formation of defects in this area. Originality. It was established that the field of displacement of the body with the inclusion in the problem under consideration is distorted slightly, which may indicate the fact that cracks are formed not by the mechanism of separation or shear, but due to the formation of zones with lower strength parameters, in particular, zones with increased damage. Practical value. To eliminate the negative impact of inclusions, it is recommended to technologically form locally gradient structures that make it possible to neutralize the negative impact of inclusions on the formation of a stressed-strained state of the structure. Scopes of further investigations. Further investigations will be conducted in the field of determining the relationship between contact strength and properties of the inclusion zone area.