Issue 78

G. Palomba et alii, Fracture and Structural Integrity, 78 (2026) 233-247; DOI: 10.3221/IGF-ESIS.78.14

useful information for designers and users in the evaluation of preferential sites for damage nucleation under monotonic or cyclic loading conditions. The integration of hardness-based material characterization and finite element simulation represents a powerful strategy, with non-destructive potential, for evaluating welded structures. This method can be extended to fatigue and fracture analyses by correlating local cyclic properties with hardness. Moreover, the approach can be automated for large-scale assessments, enabling rapid material property mapping across complex weld geometries.

C ONCLUSIONS

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comprehensive experimental–numerical analysis has been carried out to evaluate the mechanical behavior of AISI 316L welded joints using hardness-based property correlations. The combined Lopez & Fatemi and Kamaya approaches enabled accurate reconstruction of true stress–strain curves from hardness data, which were validated through tensile tests on non-welded specimens. These models were then applied to welded joints to distinguish the behavior of BM, HAZ, and WM regions. The main conclusions are summarized as follows: - Hardness variations across welded joints provide an effective indicator of local strength heterogeneity. - The Lopez and Kamaya correlations, when properly calibrated, can provide a reasonable prediction of local stress–strain behavior. - Finite element simulations incorporating local properties reproduce both global and local deformation patterns. - The applied methodology lays the foundation for the development of reliable procedures to be employed for in-service evaluation on critical components, limiting the necessity of destructive testing. The present implementation should be regarded as a laboratory-scale hardness-based characterization procedure. Although the current workflow involved sectioning and metallographic preparation, the approach indicates a possible development path toward future non destructive or minimally invasive evaluation procedures based on local hardness mapping. - Future developments will integrate fatigue correlations and microstructural characterization to extend the applicability to life prediction. The above findings should be interpreted considering that present study has some limitations. The proposed hardness-based local constitutive modelling approach was assessed under quasi-static tensile loading and on a limited number of AISI 316L welded specimens. Moreover, direct fatigue, fracture, radiographic, and fracture-surface validations were not included. Therefore, the results should be interpreted as a feasibility assessment and preliminary validation of the proposed methodology. Nonetheless, the suggested scientific approach, shows that full mechanical property reconstruction from Vickers hardness data, coupled with finite element modeling and DIC validation, is viable for TIG-welded AISI 316L joints. Therefore, the present work should be regarded as a feasibility study showing promising agreement between hardness derived local constitutive modelling, FEM predictions, and DIC observations for welded AISI 316L butt joints. This method aims to advise a roadmap toward the development of a reliable, non-destructive alternative to extensive tensile testing.

A CKNOWLEDGMENTS

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his work has been supported by the project “EMPATHY”. “Enhanced Marine Pollution Emergency Actions To preserve the Ocean Health and the safetY of ship and navigation”. Project 2022TXST8X. CUP I53D23001880006. Progetti di Ricerca di Rilevante Interesse Nazionale PRIN 2022. funded under the National Recovery and Resilience Plan (NRRP). Mission 4 Component C2 Investment 1.1 by the European Union – NextGenerationEU.

R EFERENCES

[1] D’Andrea, D. (2023). Additive Manufacturing of AISI 316L Stainless Steel: A Review, Metals (Basel). DOI: https://doi.org/10.3390/met13081370. [2] Corigliano, P., Frisone, F., Chianese, C., Altosole, M., Piscopo, V., Scamardella, A. (2024). Marine Science and Engineering Fatigue Overview of Ship Structures under Induced Wave Loads, J. Mar. Sci. Eng. 2024, 12, p. 1608. DOI: https://doi.org/10.3390/jmse12091608.

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