Structural dynamic response of a locomotive hydraulic damper with welding imperfections

Abstract

Railway vehicle hydraulic dampers are usually subject to premature structural failures, so it is meaningful to investigate the dynamic response of its welded main structure. FEA modelling of the welded rod-and-attachment assembly with imperfections of a Chinese electric locomotive axle-box hydraulic damper is performed, and load spectra of the axle-box hydraulic damper both under nominal and actual in-service conditions are obtained. Structural dynamics response analysis of the welded rod-and-attachment assembly of the damper is then conducted by using the FEA model and load spectra, and demonstrates that all of the maximum dynamic stresses have increased by 40% or so when using the actual in-service load spectra regardless of the weld joint condition, if the weld joint is with imperfection of misalignment of rod and attachment, the maximum dynamic stress has increased by 41.46%. Therefore, railway hydraulic dampers are usually subject to actual in-service load spectra instead of the nominal load spectra used in the design process, if the damper also has got welding imperfections, the damper would be readily subject to premature failures, this is why many current railway vehicle hydraulic dampers are still subject to premature failures despite with ‘perfect’ designs. The FEA model, the structural dynamic response analysis approach and results obtained in this work would be instructive in improving damper structure design, welding quality control and inspection.