Interaction between a slab track/subsoil system and a vehicle with a laterally nonsymmetric out-of-roundness of its wheels

The paper describes a semi-analytical approach for the calculation of the interaction of a 3D beam/halfspace system with a moving vehicle with wheels of given out-of-roundnesses which may be different for the front and for the rear axle as well as for the left and for the right wheels. The coupling between the laterally rigid, infinitely long beam and the 3D halfspace under bending as well as under torsion is derived according to the Integral Transform Method (ITM) with the use of shapefunctions with unknown factors for the approximation of the unknown distribution of the coupling stresses. The respective procedure allows, after the coupling of the beam and the soil is accomplished, to arrive at a description where the soil appears practically in the same form as a Winkler foundation, with the only difference that the stiffness now depends on the wavenumber k_x and the frequency ω. For the solution of the problem the principle of superposition shall be applied which allows to substitute the unsymmetrical loading by the superposition of a purely symmetric and a purely antisymmetric case. The latter causes a torsion of the beam. In order to couple the beam-halfspace structure to the vehicle, it is necessary to go back to the original spatial domain by an Inverse Fourier transformation. In this context the fact, that the vehicle moves, can be taken into account by respective transform operations. The vehicle shall be described as a 4DOF system for the roll excitation. After the investigation of the movement, the pressures between the beam and the halfspace are known and with them one can calculate the motion of the halfspace since its loading is known then. The evaluation (in a coordinate system at rest) of the wave propagation shall be considered especially in regard of effects which are caused by the nonsymmetry of the excitation.     «

The paper describes a semi-analytical approach for the calculation of the interaction of a 3D beam/halfspace system with a moving vehicle with wheels of given out-of-roundnesses which may be different for the front and for the rear axle as well as for the left and for the right wheels. The coupling between the laterally rigid, infinitely long beam and the 3D halfspace under bending as well as under torsion is derived according to the Integral Transform Method (ITM) with the use of shapefunctions...     »