Estimation of the damping effects of suspension systems on railway vehicles using wedge tests

The damping ratios of suspension systems on a railway vehicle were estimated in terms of the free-decay responses obtained by applying the logarithmic-decrement method to data obtained in wedge tests. The characteristics of the free-decay responses were measured both for motor and trailer cars experiencing either the tare loading (AW0) or crush loading (AW3) condition and either inflated or deflated air springs. The considered cases included bouncing, pitching, rolling and lateral motions. A dynamic model was established and the simulation results were compared with the experimental results. For the vertical cases, the time cycles and displacement amplitudes of the free-decay response are related to the state of the air springs and the vehicle load. The damping ratio of the secondary suspension for inflated air springs is about three to five times higher than for when the air springs are deflated. For the primary suspension, it is two to four times higher. Also the heavier the carbody loads, the much more severe is the divergence. Furthermore, the damping ratios have their largest values for the pitching modes, followed by the bouncing modes and finally the rolling modes. For the lateral cases, the free-decay responses have similar characteristics to those of the vertical responses but with smaller amplitudes. All the tests show good agreement with one another, and the primary and secondary suspensions show similar regularities. The simulations show a good agreement with the test results and highlight that the initial velocity has only a limited effect on the test results.

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  • English

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  • Accession Number: 01599970
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 4 2016 9:13AM