Responses of infinite periodic structures to moving or stationary harmonic loads

Formulae are derived for the computation of the response of periodically supported structures subject to a moving or stationary harmonic load. They are expressed in terms of an integral over the wavenumber in the longitudinal direction. The structures may be described using either a multiple-beam model, or more generally, a two-and-half-dimensional finite-element model. The supports, described by a receptance matrix, may have arbitrary degrees of freedom, either translational or rotational. Equations for free vibration propagation constants are yielded straightforwardly. Results are produced for a conventional ballasted track, showing the effects of the load speed and the modelling of the supports.