Railway Track Numerical Modelling with Geogrid Incorporation

• Autor(a) principal: Santos, Filipe Frade dos
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/143940
• topic: Railway; Finite Element Method; Numerical model; Parametric model; ANSYS Parametric Design Language; Geogrid; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Mecânica

Although rail transportation is one of the oldest ways of transportation, it is still seen as one of the major components toward the implementation of green cities, green transportation. And due to many advantages to the alternatives, growth in research and investment has been observed in the past decades. With the tools available today, a considerable part of the research, not only structural mechanics but in many other of the engineering world, is conducted with the aid of computational models. This dissertation aims at: developing a fully parametric numerical model of the railway track using ANSYS, allowing the study of different particular track sections easily; including a geogrid in the model and evaluate its influence on the railway track behaviour. The development of the numerical model with ANSYS Parametric Design Language (APDL) code goes through many stages, namely the definition of: geometry, material model, mesh/elements and boundary conditions. Then, static and transient analyses are carried out to compare the vertical displacement as well as the settlement in short-term (50 cycles) with a full-scale laboratory model results. The laboratory model results are used to compare with simulations with different material model characteristics, namely the initial yield stress and tangent modulus used to define the initiation and progression of plastic deformation of the ballast and sub-ballast layers. The short-term numerical model behaviour achieved is very close to the laboratory model which, with all the parameters made available, means that it is, in theory, possible to reliably simulate many particular railway track sections. Moreover, the incorporation of the geogrid in the model is tested with different characteristics and brought, as intended and expected, an improvement in permanent vertical settlement results.