ON INCREASE OF AXIAL LOAD

Studies show that the stress state in the contact area is achieved by pressure in the contact area, which influences the stress. Thus, considering the Hertz contact of a spherical indenter with elastic halfspace, Huber [1] determined stresses in the cartesian reference system by a set of expressions [2]. It is easy to see that the state of stress for each point is determined by the average pressure and physical characteristics of contacting materials and coordinates of the point in question. The objective of the authors was to investigate influence of increasing axial load on the wheel-rail interaction, stress state in the area of contact and wear rate of contacting surfaces, using mathematical tools and engineering methods.

As the result of detailed calculations the authors note that there is an increase of principal stresses and pure shear stress is outside the contact area. As wear is proportional to the applied force, the wear rate of wheel and rail surfaces increases. The authors emphasize the need to study the effect of increasing the load on other elements of the rolling stock, track superstructure, roadbed. It is known that productivity of railways can be improved by increasing crossing capacity and carrying capacity. In turn, carrying capacity at constant geometrical parameters of rolling stock units can be increased with increasing axial load. And that again entails changing the state of stress in the contact area of wheel and rail. The article deals with some of the problems arising in the elements of the rolling stock and track superstructure, but does not consider the effect of increasing the load on the roadbed, artificial structures, longitudinal forces in the train, its stability, etc. Hence the authors declare a need for a thorough and comprehensive study to present all the inevitable interdependences in the complex.

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