Fatigue Analysis of A Railway Hydraulic Damper with Welding Imperfections under Actual In-service Load Conditions

Abstract

. Fatigue analysis of a railway vehicle axle-box hydraulic damper was carried out in this study. The damping force profiles under nominal and actual in-service load conditions were simulated, and the corresponding load spectra were obtained using the rain-flow cycle counting approach. Further fatigue analyses of the hydraulic damper under nominal and actual in-service load spectra and with welding imperfections were conducted. Results demonstrate that the maximum local stress of the damper would increase and fatigue life would be remarkably reduced when using the actual in-service load spectra. If the damper also has multiple welding imperfections, such as with porosities and misalignment of parts, the damper would be readily subject to premature failures. For this reason, many current high-speed rail hydraulic dampers are still subject to premature failures despite being designed to nominal load cases. Thus, a nonlinear in-service damper model and the actual in-service load spectra should be used in further damper structural development, the results obtained in this study could also be instructive in improving damper structure welding technique and inspection.