To accurately evaluate the fatigue life and reliability of complex structures
a weak point selection method for complex structures with multi-variable reliability model is proposed. The impact of load uncertainty
material properties uncertainty
number of load application
and material strength degradation for the fatigue life and reliability are taken into account
and a standard for other mechanical structures to determine their weak points is provided. A metro-train bolster is taken as an example to show the specific calculation process of selecting weak points by the multi-variable reliability model in detail and the fatigue reliability is evaluated. The results indicate that only two weak points among 28 potential weak points determined by stress concentration criterion are the real ones affecting the fatigue reliability of the bolster
the bolster meets the 30-year design requirement for safe service
and its cumulative failure probability is only 0.75% within the 60 year service.
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references
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