Rolling Contact Fatigue Life Evaluation Using Weibull Distribution

Abstract

Surfaces subjected to rolling and sliding contacts may suffer from contact fatigue. This text deals with solid mechanic aspects of contact fatigue including the description of experimental study on contact fatigue. This document describes the methodology used in MS Excel for evaluation of component survival probability by Weibull distribution in application for evaluation of contact fatigue survival probability. Introduction. Contact stresses and deformations are those that have their origin in the mutual contact of objects, realized by tiny contact areas. Principles of the contact mechanics can be applied for example for calculation of contact stresses between teeth of gear sets, within roller bearings, between the wheel and a rail of rail vehicles, etc. When two solid bodies are brought into a contact, the deformation occurs at or very close to the areas of the true contact, so we have to consider that the stress is three-dimensional. The Hertzian contact stresses (pressures) have a local character and that is the reason why their values, together with the distance from the contact area, decrease rapidly. Stresses that occur, when solving contact tasks, cannot be considered as the linear function of loads, because with the change of the load power, dimensions of the contact area are also different [1]. In the reliability engineering, failure analysis and survival analysis many statistical methodologies are used. In the article measured data were analysed using the Weibull distribution that is a continuous probability distribution, the gradients of which directly inform us about the shape and scale parameters corresponding to the characteristic life and failure rate of the specimen. Methodology for the Weibull distribution calculation in the commonly used MS Excel environment is also described.