Finite Element Algorithm for Fatigue Crack Initiation Life Modeling of Railway Coupler Knuckle Under Hybrid Load Spectra

This study employs the compiled longitudinal coupler load spectrum of the Da-Qin Line 20,000-ton heavy-haul trains to calculate fatigue life for 20 couplers. Utilizing the steady-state approach within the Local Stress-Strain Method (LSSM), the analysis specifically accounts for localized plastic deformation effects. Furthermore, considering the stochastic positioning of couplers within train formations, a hybrid load spectrum methodology was implemented. This approach enables the derivation of generalized fatigue life predictions for hook tongues across the Da-Qin Line coupler population.