IDENTIFICATION OF DYNAMIC PROPERTIES OF A RAILWAY TRACK

摘要

The paper presents a methodology for assessment of dynamic characteristics of a railway track in application to an Embedded Rail Structure. First, the dynamic responses of a track are obtained using a Hammer Excitation Test (HET) by applying a vertical impulse load to a rail and measuring resulting accelerations of a track. The measured data is then analyzed using the Frequency Response Function (FRF). The hammer test is also simulated by the finite element model (RAIL), which can be used for analysis of the dynamic behavior of a track under various loading. Both HET and RAIL are developed at Delft University of Technology (DUT). To match the simulation and measurement data a numerical optimization technique called a Multipoint Approximation based on Response Surface fitting (MARS) method has been used. The parameters of the model related to the material properties of elastic compound (polyurethane and cork mixture) wherein the rails are embedded have been varied during the identification process. The numerical model with the obtained parameters of compound can then be used for estimation of performance characteristics of the railway track. The compound parameters have been compared with the ones obtained using a single degree of freedom mass-spring system. The results of the identification problems are presented and discussed.