Fatigue behaviour of EA4T notched specimens: experiments and predictions using the theory of critical distance

Abstract

As a fatigue-sensitive component, the reliability of railway axles is critical for the safe service of high-speed trains. Fatigue is a localized process involving the nucleation and growth of cracks to failure, especially sensitive to local geometrical discontinuities. Unfortunately, in the manufacturing, operation and maintenance of railway axles, some kinds of microscopic notches are inevitably introduced. Therefore, it is important to study the notch effect on the fatigue performances of railway axle steels. Accordingly, rotating bending fatigue tests of smooth and notched specimens were conducted, in consistency with the actual service load pattern of railway axles. Finally, the theory of critical distance (TCD) was introduced for studying the fatigue behaviour of different specimens, which correlates the S–N curves of three kinds of specimens well when regarding the critical distance as a life dependent variable.