Experimental characterization and numerical modeling on the external impacting of high-speed railway axle EA4T steel

Abstract Modern railway axles are prone to external impacts under in-service, leading to fatigue crack initiation and failure accidents. In this work, the impacting responses of railway axles induced by foreign object damage (FOD) were investigated by using finite element modelling with the Johnson-Cook (J-C) constitutive law and failure model. J-C material model parameters of railway axle EA4T alloy steel were determined by the quasi-static compression test, Split-Hopkinson pressure bar test and high-speed tensile tests at room temperature and high temperatures. For validation purpose, typical FOD craters were generated using the air gun device at two impacting velocities of 100 m/s and 138 m/s. Based on statistical size and morphology as well as residual stress distribution around the crater, it can be concluded that the derived J-C material model can effectively depict the impacting behavior of EA4T alloy steel. It is also observed that the dimensions of the defect and the residual stress are positively correlated with the assumed running speed of railway vehicles.