TTB-2D: Open-source 2D Train-Track-Bridge numerical model

This article introduces an open-source implementation capable of modelling the train-track-bridge interaction problem with a moderate level of complexity. The software is called TTB-2D and has been implemented for Matlab. The Train-Track-Bridge (TTB) problem is modelled in a 2-dimension representation. In this model, the train is represented as a succession of multiple wagons, where each individual vehicle can be represented as a combination of linear spring and dashpot elements together with rigid bodies and lumped masses. The train travels over a track that includes rail irregularities, the rail, pads, sleepers, ballast, and sub-ballast. Part of the track is resting over a bridge, which is modelled as a beam using a finite element formulation. The support conditions of the bridge are customizable, enabling the representation of a wide range of structural configurations. The numerical solution of the combined Train-Track-Bridge system accounts for the coupling effect of the vehicle-infrastructure interaction. The software implementation and variable definitions have been designed aiming for simplicity and readability, to achieve steep learning curves for the potential users and enable future additional developments by the community. This paper provides an overview of the software. The main features of the model are highlighted, and a brief guidance on its use is provided. In addition, this document provides a review of past examples where it has been employed successfully in published scientific article. The author believes that TTB-2D constitutes a great tool for researchers starting to work in the field of railway bridge dynamics under traffic loading.