A Wheel-Rail Force Identification Method Based On The Wheelset Finite Element Model

The force between wheels and rails becomes more and more intense with the increasing of velocity of high-speed trains,therefore the accurate identification of wheel-rail force has important significance to the safe operation of trains.The instrumented wheelset technology is the most accurate and effective wheel-rail force identification method.In this paper,the theory and method of identification of the wheel-rail forces are studied based on the method of instrumented wheelset and finite element analysis.The experimental modal parameters of a scaled wheelset are obtained by modal testing and the computational modal parameters are obtained by finite element analysis.Then a model updating process based on sensitivity analysis is carried out to optimize the finite element model.Interference and friction coefficient are taken as research parameters to analyze the influence of interference fit on the strain distribution of wheels and to determine the connection of wheelset axis and hubs in the finite element model.Finally,the accurate finite element model of the scaled wheelset is obtained.Strain distribution on the wheel is obtained by static analysis.Two kinds of Wheatstone bridges which can remove harmonics on the wheel are proposed and proved theoretically.On this basis,a method of wheel-rail force identification considering the strain of wheel and axle is proposed.Traditional sensitivity matrix is replaced by transition matrix.Besides,the condition number of transition matrix can be effectively controlled by adding the principal component weighted iteration method to wheel-rail force identification.The calibration experiment is designed and completed to verify the identification algorithm and the ability of harmonic elimination for bridges.A toolbox,for the identification of surface nodes in finite element model and wheel/rail force,is developed to provide friendly human-machine interface for research and engineering application based on MATLAB GUI programming technique.The reliability of the toolbox is verified by an example.