Issue 45

D. Peng et alii, Frattura ed Integrità Strutturale, 45 (2018) 33-44; DOI: 10.3221/IGF-ESIS.45.03 33 Effect of corrosion and fatigue on the remaining life of structures and its implication to additive manufacturing D. Peng, R. Jones Centre of Expertise for Structural Mechanics, Department of Mechanical and Aerospace Engineering, Monash University, P.O. Box 31, Monash University, Victoria, 3800, Australia. F. Berto, S.M.J. Razavi Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway A BSTRACT . This paper investigates the combined effect of corrosion and fatigue on the growth of cracks that arise from natural corrosion in steel bridges. It is shown that if these two effects need to be simultaneously analyzed. If not, then the resulting life is not conservative. Consequently, to enable a better understanding of the remaining life of steel bridges this paper presents a simple methodology for performing this coupled analysis. The implication of this study to additively manufactured Ti-6Al-4V is also discussed. K EYWORDS . Steel bridges; Corrosion; Fatigue crack growth; Remaining life. Citation: Peng., D., Jones, R., Berto, F., Razavi, S.M.J., Effect of corrosion and fatigue on the remaining life of structures and its implication to additive manufacturing, Frattura ed Integrità Strutturale, 45 (2018) 33- 44. Received: 02.05.2018 Accepted: 25.05.2018 Published: 01.07.2018 Copyright: © 2018 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION t has long been known that the corrosion of steel bridges can have a marked effect on structural integrity. Indeed, the collapse of the I35W bridge in Minneapolis, USA led US Rep. Michael Conway (R-TX11) to introduce the Bridge Life Extension Act of 2008. Transportation for America subsequently conducted an analysis of the US National Bridge Inventory [1] and reported that one in nine U.S. bridges were rated as being structurally deficient. In this context it should be noted that for steel bridges the primary problems essentially result from either corrosion due to exposure of the steel to atmospheric conditions and/or from small non-detectable initial material discontinuities [2]. As a result, the US National Cooperative Highway Research Program, NCHRP Synthesis study [2] highlighted the need to develop advanced fatigue life calculation procedures that were capable of accounting for non-visible cracks in steel bridges. Indeed, the need to be able to account for small sub mm initial defects is reinforced in the US Federal Highway Administration Steel Bridge Design Handbook [3] where it was noted that crack growth essentially starts from day one and that the majority of the life of steel