PSI - Issue 66

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 66 (2024) 370–380

8th International Conference on Crack Paths Residual Stress Effect on Crack Closure in Additively Manufactured Stainless Steels Aditya Khanna a *, Andrei Kotousov b , Andrew Sales b,c

a School of Mechanical and Mining Engineering, The University of Queensland, Brisbane QLD 4072, Australia b School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide SA 5005, Australia c AML3D Limited, 35 Woomera Avenue, Edinburgh SA 5111, Australia

Abstract Super duplex stainless steels (SDSS) are extensively used in oil and gas, marine, and chemical process industries. Recently, wire arc additive manufacturing (WAAM) has been demonstrated as an attractive method for fabricating near net-shape structural components from SDSS. This manufacturing technique can introduce a complex residual stress field, which could significantly influence the fatigue lifetimes of the manufactured parts. Moreover, residual stresses can affect the evaluation of fatigue properties by changing the effective stress ratio. This study investigates the effect of residual stresses on crack tip closure values at different stress ratios. For this purpose, CT specimens were fabricated from the printed plate and starter notches were machined in the specimens either parallel or perpendicular to the weld deposition directions. No heat treatment was applied to the machined specimens. The crack growth rates, crack closure loads, and residual back face strain were evaluated experimentally in the Paris regime of long crack growth. The open crack compliance method is used to estimate the contributions of the residual stress field to the crack tip closure values and the effective stress intensity factor range. It was demonstrated that accounting for the residual stresses leads to a notable reduction in the scatter of experimental results. In general, the current work contributes to the development of testing procedures for the evaluation of intrinsic fatigue properties, i.e. material properties, which are not affected by the loading history and the presence of residual stress field. © 2025 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 CP 2024 Organizers Keywords: Residual stress; Crack Closure; Additively Manufactured Alloys; Fatigue crack growth testing © 2025 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 CP 2024 Organizers

* Corresponding author. Tel.: +61-7-336-54264. E-mail address: aditya.khanna@uq.edu.au

2452-3216 © 2025 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 CP 2024 Organizers

2452-3216 © 2025 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 CP 2024 Organizers 10.1016/j.prostr.2024.11.088