Fatigue Reliability Assessment of a Metro-Train Bolster  
Author Jiexin Hu

 
Co-Author(s) Liyang Xie; Haiyang Yu; Longxi Liu; Weiguang Sun

 
Abstract The bolster is one of the key structures of a metro train. To evaluate its fatigue lifetime, a full-scale fatigue test was performed. The fatigue loading scheme was derived from the international standards, and the Von-Mises stresses used to verify the validity of finite element model were measured by the strain gauges during test. The bolster was treated as a series system with stress concentration zones, and their stresses were calculated using the verified model. Since no fatigue crack was observed after test and the fatigue lifetime got from Goodman diagram is more than 1×107 load cycles, the bolster’s service life is more than 30 years with 90% reliability. In addition, to learn more about its fatigue reliability, a fatigue reliability model for the metro-train bolster was established based on stress-life interference model. In the fatigue reliability assessment, 10 load spectrums were generated by Poisson processes, and the bolster was also treated as a series system with 6 weak points. As a result, not only does this bolster meet its service requirement, but also its cumulative failure probability is less than 0.002% in the atmospheric environment within its 30-year service.

 
Keywords Metro-train bolster, full-scale fatigue test, fatigue reliability, series system, reliability model
   
    Article #:  24237
 
Proceedings ISSAT International Conference on Reliability and Quality in Design 2018
August 2-4, 2018 - Toronto, Ontario, Canada