Fatigue Life Optimization of Simple Turnout in Ballasted Track
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Date
2016-07
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Addis Ababa University
Abstract
Turnouts are very important components in railway infrastructure for facilitating changes in direction and shift in track that trains are moving. Therefore, various discontinuities are introduced at turnouts which affect the dynamic interactions and increase the damage severity on the turnout and on the trains using the turnout. The annual investment of funds to construct and maintain a viable track system is enormous. Then optimum use of these funds is a challenge which demands the best technology available. Therefore, research on fatigue life optimization of simple turnout in ballasted tracks, which are the very critical elements in railway infrastructure, worth researching a lot.
In this research, multiple cases of virtual experiments, based on design of experiment approach have been done to come up with an optimal parameter combination which gives maximum fatigue life or minimum cumulative damage. Numerical mechanical dynamic simulation in an MBS environment SIMPACK on a computer run and then a finite element simulation finally done on ABAQUS based on the optimum parameter combination obtained in the MBS simulations to determine fatigue life. And lastly results have been compared between the MBS and FE dynamic simulation then interpretations made after that.
The results show that an optimum fatigue life will be obtained if the rail-pad vertical stiffness is 300MPa and effective sub-structure stiffness is 110MPa. And the optimum fatigue life is calculated to be 1.1years as per the MBS result and 1.2years from the FE result. Possible reasons for the discrepancy in life prediction have been forwarded with ways in maximizing the accuracy and precision.
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Keywords
Simple Turnout, Multi-Body-System, finite element, modeling and simulation, fatigue life, optimization