Issue 48

J. F. Barbosa et alii, Frattura ed Integrità Strutturale, 48 (2019) 400-410; DOI: 10.3221/IGF-ESIS.48.38 400 A comparison between S-N Logistic and Kohout-Věchet formulations applied to the fatigue data of old metallic bridges materials Joelton Fonseca Barbosa Federal University of Rio Grande do Norte, Natal, Brazil & Federal Rural University of the Semi-Arid Region, Mossoró, Brazil Faculty of Engineering, University of Porto, Porto, Portugal joeltonfb@gmail.com, https://orcid.org/0000-0003-3447-8240 José A.F.O. Correia, Pedro A. Montenegro Faculty of Engineering, University of Porto, Porto, Portugal jacorreia@inegi.up.pt , jacorreia@fe.up.pt , https://orcid.org/0000-0002-4148-9426 paires@fe.up.pt, http://orcid.org/0000-0001-5699-4428 Raimundo Carlos Silverio Freire Júnior Federal University of Rio Grande do Norte, Natal, Brazil freirej@ufrnet.br Grzegorz Lesiuk Faculty of Mechanical Engineering, Department of Mechanics, Material Science and Engineering, Wrocław University of Science and Technology, Smoluchowskiego 25, 50-370 Wrocław, Poland Grzegorz.Lesiuk@pwr.edu.pl , https://orcid.org/0000-0003-3553-6107 Abílio M.P. De Jesus, Rui A.B. Calçada Faculty of Engineering, University of Porto, Porto, Portugal ajesus@fe.up.pt , http://orcid.org/0000-0002-1059-715X ruiabc@fe.up.pt , http://orcid.org/0000-0002-2375-7685 A BSTRACT . A new formulation of a Logistic deterministic S-N curve is applied to fatigue data of metallic materials from ancient Portuguese riveted steel bridges. This formulation is based on a modified logistic relation that uses three parameters to fit the low-cycle- (LCF), finite-life- and high-cycle- fatigue (HCF) regions. This model is compared to the Kohout-Věchet fatigue model, which has a refined adjustment from very low-cycle fatigue (VLCF) to very high-cycle fatigue (VHCF). These models are also compared with other models, such as, power law and fatigue-life curve from the ASTM E739 standard. The modelling performance of the S-N curves was made using the fatigue data considering the stress fatigue damage parameter for the materials Citation: Barbosa, J., Correia, J., Montenegro, P., Júnior, R., Lesiuk, G., Jesus, A., Calçada, R., A comparison between S-N Logistic and Kohout-Věchet formulations applied to the fatigue data of old metallic bridges materials, Frattura ed Integrità Strutturale, 48 (2019) 400-410. Received: 22.10.2018 Accepted: 27.12.2018 Published: 01.04.2019