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Description
The interaction between vehicles moving on a continuous elastic medium and underlying support layers generates induced vibrations that may affect surrounding structures. In environmental impact studies for proposed and planned new railway lines, it is frequently necessary to characterize vibration intensities for different track support structural packages. For train systems, in addition to the mechanical properties of the foundation package, both rail roughness and wheel roughness (flat- wheel conditions) become particularly relevant. This work develops a modeling approach for parametric analysis of such systems, employing a matrix assembly methodology in generalized coordinates along with global interpolation functions for the rail (modeled as a constant-section Euler-Bernoulli beam) and discrete coordinates to represent sleeper kinematics and elastic support medium deformation. Rail deformation is approximated through superposition of a Fourier basis with interpolation functions ac- counting for rigid body displacements of the rail. The implementation of global interpolation functions and the orthogonality properties of the rail deformation interpolation functions enable efficient assembly of the system’s motion equations matrices (some being time-variant) for the coupled vehicle-track model incorporating rail, sleepers, and elastic foundation support. Through numerical integration of the linear time-variant model, rail vibrations are analyzed under the assumption of rigid wheel-rail contact. Results from this primary model are compared with a mass-mass coupling model using a time-domain metric.