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Discrete Element Modeling of Railway Ballast Toward Improved Tamping Practices

项目名称：	Discrete Element Modeling of Railway Ballast Toward Improved Tamping Practices
摘要：	The development of Discrete Element Model (DEM) of railway ballast for the purpose of studying the behavior of ballast particles during tamping is addressed in a simulation study. The research aims at optimizing the railroad tamping operation. A comprehensive literature review of applicability of DEM techniques in modeling the behavior of railway ballast has been conducted. The feasibility of DEM methods in studying the fundamental mechanisms that dictate the outcome of railroad tamping process has been analyzed. Using a DEM-based commercial software, a simulation model of the dynamics of railway ballasts during tamping has been developed and validated. The selection and calibration of ballast parameters, such as inter-particle contact force laws, ballast material properties, and selection of particle shape in the model have been evaluated in detail. Finally, a complete tamping simulation model has been constructed with high degree of adjustability to allow control of all process parameters for achieving realistic output. An analysis of the modeling results shows that DEM is a highly valuable tool for studying railroad tamping operation. It has the capability to provide crucial and unprecedented insights into the process, facilitating not only the optimization of current tamping practices, but also the development of novel methods for achieving sustainable improvements in track stability after tamping in the future. Different ways of modeling particle shapes have been evaluated and it has been shown that while using spheres to represent irregular ballast particles in DEM provides large gains in computational efficiency, they cannot capture all properties of irregularly-shaped particles. Additionally, the results indicate that the model is able to accurately predict properties of granular assemblies of the railway ballast in different test cases. The half-track model that has been developed thus far can be extended in future studies for evaluating rail track settlement and stability, optimization of tamping process, and performance of different ballast gradations.
状态：	Active
资金：	180000
资助组织：	Office of the Assistant Secretary for Research and Technology
管理组织：	Virginia Polytechnic Institute and State University, Blacksburg
项目负责人：	Ahmedian, Mehdi
执行机构：	Virginia Polytechnic Institute and State University, Blacksburg
主要研究人员：	Ahmedian, Mehdi
开始时间：	20180101
预计完成日期：	20191231
实际结束时间：	0