PSI - Issue 13

Stanislav Seitl et al. / Procedia Structural Integrity 13 (2018) 1494–1501 Author name / Structural Integrity Procedia 00 (2018) 000–000

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5. Conclusions The S-N curves and the rates of growth of long fatigue cracks were experimentally investigated in two rolling direction A, B of high strength S355 J0 steel grade. The following conclusions can be drawn:  Two different models representing two alternative methodologies both for evaluation of the S–N field and evaluation of the crack propagation rate in the Paris region were applied to the fatigue data assessment of S355 J0 steel grade for two rolling directions, and a comparison of the results performed.  The ProFatigue program, based on the regression Weibull model proposed by Castillo-Canteli, provides a probabilistic analytical way of assessing fatigue results.  The extrapolation outside the lifetime ranges implied in the tests is possible. In principle, a fatigue limit is estimated with this model, although accordingly to the results this limit may prove to become zero or not.  The ProPagation program, based on the regression Gumbel family model proposed by Castillo et al., provides a probabilistic analytical way of assessing results in fatigue of cracks components.  The S355 J0 A – perpendicular to rolling direction exhibits higher crack growth rates comparing to the S355 J0 B – parallel to the rolling direction, though differences between both are small. From the engineering point of view, the crack growth rates can be considered to be independent of the rolling direction and resulting structure.  For a reliable assessment of the stress intensity factor threshold, as a model parameter in the ProFatigue software, test results in the lower part of the crack growth rate curve are required. Acknowledgements The Czech Science Foundation under the contract No. 17-01589S supported this research. This paper has been worked out under the “National Sustainability Programme I” project “AdMaS UP – Advanced Materials, Structures and Technologies” (No. LO1408) supported by the Ministry of Education, Youth and Sports of the Czech Republic. References Allen, E.J., 2018, SED models with exponential drift and diffusion for approximating fatigue crack growth dynamics, Engineering Fracture Mechanics, 200(2018) 75-85, doi: 10.1016/j.engfracmech.2018.07.013 ASTM E647 - Standard test method for measurement of fatigue crack growth rates. In Annual book of astm standards, American Society for Testing Materials: 1991; Vol. 3, 591–629 Basquin, O. H., 1910, The exponential law of endurance tests. In Proc. ASTM 10, II: 625–630 Bozkurt, F. Schmidova, E., 2017, Fracture Toughness Evaluation of S355 Steel Using Circumferentially Notched Round Bars, Periodica Polytechnica Transportation Engineering, 1–5 Branco, R., Antunes, F.V., Ferreira, J.M., Silva, J.M. Determination of Paris law constants with a reverse engineering technique. Eng. Fail. Anal. 2008, 16, 631–638 Fernández-Canteli, A., Przybilla, C. Nogal, M., Lopez Aenlle, M. Castillo, E., 2014, ProFatigue: A software program for probabilistic assessment of experimental fatigue data sets, Procedia Engineering 74, 236–241 Castillo, E., Fernández-Canteli, A., 2001, A general regression model for lifetime evaluation and prediction, International Journal of Fracture, 107, 117–137 Castillo, E., Fernández-Canteli, A., 2009, A unified statistical methodology for modelling fatigue damage, Springer. Castillo, E., Fernández-Canteli, A., Siegele, D., 2014, Obtaining S-N curves from crack growth curves: an alternative to self-similarity, International Journal of Fracture 187(1), 159–172 De Jesus, A.M.P.; Matos, R.; Fontoura, B.F.C.; Rebelo, C.; Simões da Silva, L.; Veljkovic, M. A comparison of the fatigue behavior between s355 and s690 steel grades. J. Construct. Steel Res. 2012, 79, 140–150 Dinas, A., Nikolaidis, T, N., Baniotopoulos, C.C., Sustainable restoration criteria for a historical steel railway bridge, Procedia Environmental Sciences 38 (2017) 578–585 Ellyin, F. Fatigue Damage, Crack Growth and Life Prediction, Chapman & Hall, 1997. Kala, Z., 2017 Identification of stochastic interactions in nonlinear models of structural mechanics, AIP Conference Proceedings, (2017) 1863,480004 Kala, Z., Omishore, A., 2016, Fuzzy stochastic approaches for analysing the serviceability limit state of load bearing systems, International Journal of Mathematics and Computers in Simulation 10 (2016) 294–301. Kala, Z., Omishore, A., Seitl, S., Krejsa, M., Kala, J., The effect of skewness and kurtosis on the probability evaluation of fatigue limit states, International Journal of Mechanics, 11 (2017) 166-175.