Modeling Rail-Vehicle Coupled Dynamics by a Time-Varying Substructuring Scheme

The dynamic interaction between a flexible rail line and a traveling wheel can be treated in the framework of dynamic substructuring, assembling line and wheel through a moving contact point. The rail line is idealized as a continuous beam supported by the sleepers. It is discretized by the finite element method assuming the displacement and rotation of the support points as degrees of freedom. Besides, the particular solution of the static equation is included for the beam portion that is directly loaded by the moving wheel. The wheel is modelled as a dynamical system comprising two masses connected by visco-elastic devices. Following a dual assemblage approach, the equation of motion is obtained in the form of a set of linear time variant ordinary differential equations, whose unknowns are the rail line degrees of freedom, the displacement of the sprung and unsprung masses of the moving wheel and the contact rail-wheel force.