PSI - Issue 64

Hamid Dahaghin et al. / Procedia Structural Integrity 64 (2024) 1192–1199 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Additionally, Fig. 14 highlights the presence of dislocation pileups near the crack tip due to stress concentration, resulting in the formation of microvoids and the creation of dimples. 5. Conclusion In this study, the WAAM technique was employed to enhance the fatigue resistance of damaged steel plates. Two cracked steel plates underwent WAAM repair using either the deposited or a machined and were tested under fatigue loads. FE simulation predicted RS and also provided insight into the repair mechanism. The key findings from the study are as follows: 1. The WAAM repair reduces the stress state at the existing crack tips by introducing stiffener and generating a compressive stress field in the steel substrate. In the end, the crack did not propagate from the existing crack in both WAAM-repaired samples. 2. The WAAM deposition induces a geometrical discontinuity; it generates high tensile RS at the edges of the WAAM deposited and base plate interface. These two effects may lead to new positions for fatigue crack initiation and eventually hinder fatigue life improvement in the cracked specimens due to WAAM. 3. Machining the WAAM-repaired provides a smoother transition from base plate to WAAM material and also releases some of the tensile RS. Therefore, it dramatically reduces the stresses at the deposition root, ensuring that no premature fatigue crack is formed at the interface of deposited WAAM and the plate. References Al-Emrani, M. (2002). Fatigue in Riveted Railway Bridges-a study of the fatigue performance of riveted stringers and stringer-to-floor-beam connections. Chalmers University of Technology. Baqershahi, M. H., Ayas, C., & Ghafoori, E. (2024). Design optimisation for hybrid metal additive manufacturing for sustainable construction. Engineering Structures, 301, 117355. https://doi.org/10.1016/j.engstruct.2023.117355. Buchanan, C., & Gardner, L. (2019). 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