| What endangers the traffic of traffic that fracture occurred of a large number of T type bolt on small-radius curve in Yuanboyuan-Dawayao area in Beijing Metro line 14. The essay discusses the practical disease of the project to for research object by establishing finite element model in Abaqus software. The model can simulate the actual working state of T type bolt in fastener system basing on non-linear contact theory. The model analyses the maximum mises stress distribution relationship of the roots of bolts under different boundary conditions by changing restraint area and position along axial direction. Basing on fourth strength theory, the essay also analyses the strength with the maximum mises stress caused by changing constraint form, and the field dynamic test in track is made to verify strength-analysis results. Field test in track corrugation and vibration are carried out, according to the test, the essay discusses the influence of vibration in T type bolt with corrugation on rails. Conclusion is obtained that:(1) When the axial restraint area is reduced, the mises stress value in root of T type bolts will increase. When the axial restraint area is reduced, T-bolts roots maximum mises stress value will increase. In case that the constraint area is stable, the maximum mises stress in root of T type bolts increases as the constraint position moving away from the axis of the bolt.(2) The maximum mises stress appears at the root of 1/2 at both sides of the axial position and T type bolts breakage spread downward gradually from the spherical surface.(3) Vibration analysis shows that when the train speed at 80km/h and with a wavelength of line typical corrugation 10-30mm of presence, T-bolts the first and second modal natural frequency of T type bolts are in a typical corrugation. Meanwhile T-bolts vibration excitation frequency test results under 80km/h speed are similar with the first modal natural frequency, thus there exists resonance phenomenon on T type bolts in the line. |
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