PSI - Issue 83

Goran Vukelić et al. / Procedia Structural Integrity 83 (2026) 57– 62

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Assessing how marine environments affect the mechanical performance of structural materials is essential for the reliable design and operation of marine infrastructure (Ghoncheh et al., 2024). In the present study, engineering stress– strain diagrams were derived from uniaxial tensile tests conducted on welded specimens after exposure to seawater for periods of one, three, and six months. Each experimental condition included five specimens, and the reported curves represent the averaged response of these samples. Figure 3 summarizes the measured ultimate tensile strength values for specimens subjected to different exposure durations in the marine environment, presented together for direct comparison. Trend lines were fitted to the experimental results to illustrate the relationship between tensile strength and exposure time. The corresponding coefficients of determination ( R ²) are also provided to assess the quality of the approximation. This statistical indicator reflects the level of agreement between the measured data and the polynomial model, thereby demonstrating how well the fitted curve describes the observed variation in tensile strength.

Fig. 3. Change of ultimate tensile strength for CM-CM, AM-AM, and CM-AM welded AISI 316L steel exposed to the natural marine environment for one, three, and six months. The energy-dispersive spectroscopy (EDS) oxygen maps, Figure 4, illustrate the distribution of oxygen on the surface of AISI 316L stainless steel after different exposure periods in the marine environment.

Fig. 4. EDS analysis of AM specimen surface for one month (M1), three months (M3) and six months (M6) of exposure, along with a reference kept at room atmosphere (RA).