Issue 45

L.M. Viespoli et alii, Frattura ed Integrità Strutturale, 45 (2018) 121-134; DOI: 10.3221/IGF-ESIS.45.10 121 Fatigue life assessment for a welded detail: advantages of a local energetic approach and experimental validation Luigi Mario Viespoli, Filippo Berto Norwegian University of Science and Technology, Norway luigimv@stud.ntnu.no, filippo.berto@ntnu.no Aurelio Somà Politecnico di Torino, Italy aurelio.soma@polito.it A BSTRACT . In modern civil buildings, as well as in mechanical and naval constructions, welding is a widely diffused technological process. The fatigue assessment, as design or verification procedure, of a welded joint to evaluate his endurance with respect to a load spectrum is a challenging but of paramount importance procedure. Several techniques have been proposed in the literature, constantly researching efficient, cost effective and reliable methods to predict the behavior of a complex welded structures. Some of them are part of norms and standards which any design engineer must respect. The aim of the present work is to compare the results provided by some of the principal fatigue life assessment procedures for welded joints, focusing the attention on the stress intensity factor evaluation by the use of numerical methods. Finally the proposed numerical method has been experimentally validated. K EYWORDS . Welding; fatigue; Strain energy density; Crack initiation; structural steel; Finite element analysis Citation: Viespoli, L. M., Somà, A., Berto, F., Fatigue life assessment for a welded detail: advantages of a local energetic approach and experimental validation, Frattura ed Integrità Strutturale, 45 (2018) 121-134. Received: 27.04.2018 Accepted: 26.05.2018 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 or the fatigue life evaluation of a welded detail, different procedures have been proposed [1], two of the most used are the Nominal Stress and the Hot Spot Stress approaches [2]. Their diffusion is due to the relative simplicity of the techniques, which makes them ideal in a complex structure, where is necessary to perform an assessment for a great number of weldments. A drawback of these procedures is the lack of detailed information about the stress field in the area of the critical point, so their application is closely related to an extensive previous experimental work to assess the correct fatigue class for each detail in each size class. F