Modeling and Failure Analysis of a Broken Railway Axle: Effects of Surface Defects and Inclusions

In the present work, the fatigue behavior of an axle was analyzed using modeling and experimental approaches. A failed axle was used for experimental studies. The experimental results were then analyzed in order to model and predict the fatigue life of axle. The three-dimensional finite element analysis was used to simulate the fatigue behavior of axle. The growth of a machining defect, 2 μm initial crack length, was simulated versus applied cycles. The changes in the stress intensity factor as a function of crack length were modeled as well. The model predicted that after about 5 × 10⁸ cycles there was an abrupt increase in the crack length, reaching a critical value of about 65 mm at around N _f = 5 × 10⁹ cycles, indicating that the longer the crack, the higher its growth will be. The experimental results were then compared with the modeling predictions. It is shown that the latter are in a good agreement with the former. The results obtained in this study do give a basis for evaluation of single scratch or notch produced by improper machining.