Assessment of elliptical defect dimensions influence on the metal structure contact strength properties

Abstract

Based on the approaches of continual mechanics and computer simulation, a computational methodology for establishing the operational parameters of functionally graded parts depending on the dimensional characteristics of elliptical defects is proposed. For the first time, using spatially non-local models of mechanics and the FEniCS finite element package, a calculation scheme was constructed for determining the contact strength of a material depending on the ratio of the sizes of the main radii of an elliptical defect in a structure. On the example of locomotive wheel tyres, it is shown that the most dangerous for operation are elliptical “needle-shaped” hubs with a ratio of the radii of the main axes of more than 40. They can also be a source for the development of “crack-type defects” during the operation of products. The established connection between the change in the properties of railway wheels under the action of loads and the characteristics of stress concentrators indicates that the shape of the concentrator is a more dangerous factor than its volume, and allows you to determine ways to control the operational parameters of parts with the presence of stress concentrators by surface engineering methods.