Abstract
This article presents an economical and efficient way to assess the structural safety and fatigue reliability of the bolster, a key structure for the metro-train. First, its finite element model was validated based on the comparison between numerical results and experimental data of stresses and displacements recorded during a static test. Then, the fatigue life of the bolster under loading scheme was predicted using Gerber diagram, in which the validated finite element model was applied to determine the weak points, and its structural safety was also evaluated by a full-scale fatigue test and non-destructive test method. Finally, the metro-train bolster was modeled as a series system of weak points, and a new fatigue reliability model for mechanical component derived based on stress-life interference model was used to assess its fatigue reliability under the application of the design passenger number spectra. The results show that not only does this bolster satisfy the structural safety requirement during its service life, but also its fatigue reliability is more than 99.993% after 30-year service under normal atmospheric conditions.
Highlights
The metros, one kind of efficient and convenient transportations, have been constructed in many cities as economy continues to develop in China
The static test of the bolster specimen was performed on an experimental setup under the static load condition, and the finite element (FE) model was validated through comparing the stresses and deformations obtained during the test with finite element method (FEM) simulation results
In the condition of the loading scheme derived from the international standards, the fatigue life of the bolster under normal atmospheric conditions was evaluated by the Gerber diagram, in which the weak points were determined using the validated FE model, and a full-scale fatigue test
Summary
The metros, one kind of efficient and convenient transportations, have been constructed in many cities as economy continues to develop in China. From the FEM simulation results of the metro-train bolster under the fatigue loads, the stress concentration areas are located around the welding area between the side beams and the bolster, which are inside the bolster specimen and inconvenient to bond the strain gauges, and 28 weak points were selected to assess the fatigue life of the bolster by analytical studies.
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