PSI - Issue 57

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 57 (2024) 569–580

© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers Abstract Analysis results using finite elements are compared with strain measurements and laboratory fatigue testing of doubling plates used in floating production platforms. Circular and quadratic doubling plates of thickness 10 mm with diameter and length equal to 150 mm fillet welded to a main plate of thickness 20 mm were fatigue tested. The testing was performed until crack growth through the plate thickness and the number of test cycles was compared with design standards. Finite element analyses of the doubling plates were performed using different methods for hot spot stress derivation in combination with relevant S-N curves. Analyses were performed using 8-node shell elements and 20-node solid elements. Hot spot stresses were based on calculated surfaces stresses at the weld toe. Also stresses through the thickness of the main plate were used for assessment of the hot spot stress. For purpose of analyses the main attention was made to the weld toe. However, the main reason for performing the fatigue testing was related to concern for crack growth from the weld root. This failure mode was found to be less critical than fatigue crack growth at the weld toe. The results from this work are being used for developing more reliable analysis methods to be included in design standards. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers Keywords: Fatigue; fillet welde doubling plates; finite element analyis; weld roots; weld toes; fatigue design recommendations. 1. Introduction Fillet welded doubling plates are frequently being used where secondary structures are connected to the main structure in semisubmersible platforms and floating production vessels for oil and gas. The fatigue design of the weld toes at the fillet welds is well established in recommended design standards such as DNV-RP-C203 (2019) and IIW in Hobbacher (2009). A fatigue design methodology is more uncertain with respect to fatigue crack growth from Fatigue Design 2023 (FatDes 2023) Fatigue assessment of fillet welded doubling plates using different methods Inge Lotsberg and Wenbin Dong Det Norske Veritas, Vertasveien 1, 1322 Høvik, Norway

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers 10.1016/j.prostr.2024.03.063