Damage tolerance assessment of heavy-duty freight railway axles with artificial defects

Abstract

Abstract Heavy-duty freight railway axles are no less important than that of passenger ones, due to the potentially catastrophic results caused by the derailment of trains carrying hazardous substances. Intrinsic and extrinsic imperfections challenge classical design theories built based on the safe life concept, and damage tolerance assessment becomes vital for the safety and reliability of long-term serviced railway axles, as pits and scratches are common defects for heavy-duty railway axles. In this work, four-point rotating bending fatigue tests of the AAR-CM railway axle steel specimens with semi-circular and circumferential groove notches were conducted. The fatigue limit of the semi-circular notched specimen was evaluated based on the fracture mechanics theory, in which non-conservative results were obtained by the Haddad model; and the 𝑺–𝑵curves of circumferential groove notched specimens were correlated by the theory of critical distance (TCD).