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Fatigue assessment based on hot-spot stresses obtained from the global dynamic analysis and local static sub-model

Cristiane Oliveira Viana (Federal University of Minas Gerais, Belo Horizonte, Brazil)
Hermes Carvalho (Department of Structural Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil)
José Correia (Department of Civil Engineering, University of Porto Faculty of Engineering, Porto, Portugal)
Pedro Aires Montenegro (University of Porto Faculty of Engineering, Porto, Portugal)
Raphael Pedrosa Heleno (Federal University of Minas Gerais, Belo Horizonte, Brazil)
Guilherme Santana Alencar (University of Porto Faculty of Engineering, Porto, Portugal)
Abilio M.P. de Jesus (Department of Mechanical Engineering, University of Porto Faculty of Engineering, Porto, Portugal)
Rui Calçada (University of Porto Faculty of Engineering, Porto, Portugal)

International Journal of Structural Integrity

ISSN: 1757-9864

Article publication date: 1 October 2019

Issue publication date: 3 February 2021

321

Abstract

Purpose

The purpose of this paper is to evaluate the fatigue process through the dynamic analysis of the global structural model and local static sub-modelling in a critical detail using the hot-spot stress approach. The detail was studied in three different positions at the “Alcácer do Sal” access viaduct, and the methodologies from the IIW and Eurocode EN 1993-1-9 were compared.

Design/methodology/approach

In this study, the fatigue life process based on the hot-spot stress approach was evaluated using a global dynamic analysis and a local sub-modelling based on a static analysis of welded connections in the “Alcácer do Sal” railway structure, Portugal, taking into consideration the recommendations from IIW and Eurocode EN 1993-1-9. The hot-spot stresses were calculated through the static analysis of the sub-model of the welded connection for each vibration mode with the aim to obtain the temporal stresses using the modal coordinates and modal stresses of the extrapolation points. The Ansys® and Matlab® softwares were used for the numerical analysis and the hot-spot stress calculations, respectively.

Findings

The proposed methodology/approach to obtain fatigue assessment is based on the modal analysis of the global structural model and local static sub-modelling. The modal analysis was used to extract the boundary conditions to be used in the local model to determine the temporal stresses of the extrapolation points. Based on the modal superposition method, the stresses as function of time were obtained for fatigue life evaluation of a critical detail by the hot-spot stress approach. The detail was studied in three different positions.

Originality/value

In the present study, a global-local fatigue methodology based on dynamic analysis of the global structural model and local static sub-modelling of the critical detail using the hot-spot stress approach is proposed. Herein, the modal analysis of the global structural model supported by the modal superposition method was used to obtain the matrix of modal coordinates. The static analysis of the local sub-model for each mode from the modal analysis of global structural model was done to estimate the hot-spot stresses. The fatigue damage calculation was based on S-N curve of the critical detail and rainflow method. The IIW recommendation proved to be more conservative compared to the proposed rules in the Eurocode EN 1993-1-9. The global-local modelling based on dynamic analysis is an important and effective tool for fatigue evaluation in welded joints.

Keywords

Acknowledgements

This work was financially supported by: national funds through FCT – Fundação para a Ciência e a Tecnologia; UID/ECI/04708/2019 – CONSTRUCT – Instituto de I&D em Estruturas e Construções funded by national funds through the FCT/MCTES (PIDDAC); post-doctoral grant SFRH/BPD/107825/2015 provided by FCT to the first author; NORTE-01-0145-FEDER-000022 – SciTech – Science and Technology for Competitive and Sustainable Industries, co-financed by Programa Operacional Regional do Norte (NORTE2020), through the Fundo Europeu de Desenvolvimento Regional (FEDER); IN2TRACK2 – Research into enhanced track and switch and crossing system 2 funded by European funds through the H2020 (SHIFT2RAIL Innovation Programme); and Institute of Construction (IC, University of Porto). Additionally, this research work was also supported by CAPES (Coordination for the Improvement of Personnel of Graduation), CNPQ (National Council for Scientific and Technological Development) and UFMG (Universidade Federal de Minas Gerais).

Citation

Viana, C.O., Carvalho, H., Correia, J., Montenegro, P.A., Heleno, R.P., Alencar, G.S., Jesus, A.M.P.d. and Calçada, R. (2021), "Fatigue assessment based on hot-spot stresses obtained from the global dynamic analysis and local static sub-model", International Journal of Structural Integrity, Vol. 12 No. 1, pp. 31-47. https://doi.org/10.1108/IJSI-03-2019-0021

Publisher

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Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited

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