Avaliação global-local da vida em fadiga de ligações soldadas em pontes ferroviárias de carga
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Data
2025-10-13
Autores
Ferro, Karina Barth
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Universidade Federal do Espírito Santo
Resumo
In cargo transportation, railways play a complementary role in logistics by enabling the transport of large volumes with lower energy consumption. To serve this purpose, railway bridges have been constructed over the years using various materials, among which steel has gained prominence due to its versatility and the ability to span long distances with lightweight structures. In these bridges, structural details such as welded connections can feature various geometric configurations that result in stress concentration points. When combined with dynamic loading and second-order effects, these stress concentrations make fatigue one of the primary causes of failure in steel bridges. However, assessments for this type of limit state can be complex, and more accurate approaches, such as the global-local methodology, can be employed. Within this context, a fatigue life assessment is conducted on a welded connection of a railway bridge with a composite steel-concrete structure. The analysis is carried out using finite element models in the commercial software Ansys Mechanical APDL v. 2020R1, considering two modeling scales – global and local. Fatigue life is estimated using both the nominal stress method and the hot-spot stress method. Damage per vehicle passage is computed based on the stress history, followed by the estimation of the number of load cycles the structure can withstand, in accordance with the recommendations of the International Institute of Welding (IIW) and EN 1993-1-9:2005. The results indicate that for the evaluated detail, fatigue life is not infinite, even when considering the passage of the lightest type of vehicle operating on the track. Furthermore, it is evident that increases in vehicle weight and traffic speed have a significant impact on the fatigue life of the detail. Regarding standards and methodologies, the nominal stress method was found to be non-conservative for fatigue life prediction, whereas the IIW methodology yielded more conservative results than those provided by EN 1993-1- 9:2005.
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Fadiga , Elementos finitos , Ponte ferroviária , Tensão hot spot , Metodologia global-local , Fatigue , Finite element models , Railway bridges , Hot spot stress , Global-local methodology