Issue 43

P. Zampieri et alii, Frattura ed Integrità Strutturale, 43 (2018) 90-96; DOI: 10.3221/IGF-ESIS.43.06 95 Moreover, as already noted by other researchers [14], the inverse slope k of the S-N curve obtained from experimental tests is substantially greater (between 8 and 9) than the one proposed by the EC3 standard for the detail category 112. The inverse slopes and Δσ at 2 million cycles with Ps = 90% and 97.7% are reported in Tab. 1. Specimens k Δσ 90 [N/mm 2 ] Δσ 97.7 [N/mm 2 ] Not corroded 8.29 155.9 144.0 Corroded 9.05 127.7 113.7 Difference [%] 8.00 22.0 27.0 Table 1 : Summary of fatigue tests. C ONCLUSIONS n this paper, experimental tests were performed on a bolted joint (category 112 of the EC3 standard) by fatigue cyclic tests on virgin samples and on degraded samples obtained by an accelerated corrosion process. From the test results statistical reanalysis, the S-N curve (with Ps 97.7%) obtained from uncorroded samples has an inverse slope of 8.29, approximately equal to 9.05 that is the one relative to the S-N curve derived from corroded tests results, however the last curve (of corroded specimens) is moved down with respect to the not corroded curve. The results confirm that the accelerated corrosion process applied to the specimens caused a not negligible reduction of the fatigue strength of this kind of joints. A CNOWLEDGMENTS he Authors would thank to Prof. M. Quaresimin, Eng. N. De Rossi, Prof. G. Concheri and Eng. G. Savio for their contribution. R EFERENCES [1] Correia, J.A.F.O., Huffman, P.J., De Jesus, A.M.P., Cicero, S., Fernandez-Canteli, A., Berto, F., Glinka, G. Unified two- stage fatigue methodology based on probabilistic damage model applied to structural details. [2] Sampayo, L.M.C.M.V., Monteiro, P.M.F., Correia, J.A.F.O., Xavier, J.M.C., De Jesus, A.M.P., Fernandez-Canteli, A., Calcada, R.A.B. 2015. Probabilistic S-N field assessment for notched plate made of puddle iron from the Eiffel bridge with an elliptical hole. 1st ICSI. 114 (2015) 691-698. [3] Razavi, S.M.J., Peron, M., Torgersen, J., Berto, F., Mutignani, F. Effect of hot dip galvanization on the fatigue strength of steel bolted connections, Frattura ed Integrita Strutturale, 41 (2017) 432-439. DOI: 10.3221/IGF-ESIS.41.5. [4] Berto, F., Mutignani, F., Guido, E. Effect of hot dip galvanization on the fatigue behaviour of steel bolted connections, International Journal of Fatigue, 93 (2016) 168-172. DOI: 10.1016/j.ijfatigue.2016.08.02. [5] Berto, F., Mutignani, F., Tisalvi, M. Notch Effect on the Fatigue Behavior of a Hot-Dip Galvanized Structural Steel Strength of Materials, 47 (5) (2015) 719-727. DOI: 10.1007/s11223-015-9709-0 [6] Horstmann, M., Gregory, J.K., Schwalbe, K.H. 1995. Geometry effects on corrosion fatigue in offshore structural steels. International Journal of Fatigue, 17 (1995) 293–299. [7] Rokhlin, S.I., Kim, J.Y., Nagy, H., Zoofan, B., Effect of pitting corrosion on fatigue crack initiation and fatigue life. Engineering Fracture Mechanics, 62 (1999) 425-444. [8] Ernst, P., Newman, R.C. Pit growth studies in stainless steel foils. I. Introduction and pit growth kinetics, Corrosion Science, 44 (2002) 927-941. [9] Liu, Y.M., Mahadevan, S. Probabilistic fatigue life prediction using an equivalent initial flaw size distribution, International Journal of Fatigue, 31 (2009) 476-487. [10] Shan-hua, X., You-de, W., Estimating the effects of corrosion pits on the fatigue life of steel plate based on the 3D profile. International Journal of Fatigue, 72 (2015) 27-41. I T