PSI - Issue 84

Martina Giglio et al. / Procedia Structural Integrity 84 (2026) 9–16 M. Giglio et al. / Structural Integrity Procedia 00 (2026) 000–000

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condensation environment. This choice is motivated by the fact that this cyclic exposure reproduces the hygrothermal fluctuations typical of service environments, where moisture levels cyclically transition between condensation, forming a thin water film, and subsequent evaporation, accelerating the natural phenomena of atmospheric exposure conditions. Both groups were placed in thermostatic baths maintained at 40 °C and 100 % relative humidity (Figure 3). 3.2. Monitoring protocol and signal acquisition Each RFID tag possesses a unique identification code, which is detected at each interrogation. For every tag, both the ID code and Received Signal Strength Indicator (RSSI) were recorded. Measurements were performed every three hours daily to capture short-term RSSI fluctuations induced by multiple factors, including operator position, sample positioning, proximity of other tags, and environmental parameters (temperature and humidity). The reference tag (colored curves) served as a baseline to account for variations unrelated to corrosion. Initially, the metallic layer on the working tag reflects the reader signal, and only the reference tag is detected. Once the metal layer degrades sufficiently, the working tag signal can be detected alongside the reference tag, providing two RSSI readings for the same sample. At this stage, a standardized detection procedure was applied: • If the working tag RSSI was not detected the sample was returned to the thermostatic bath for continued exposure. • If both tags were detected, such as the working and the reference tag RSSI, it indicated full degradation of the metallic layer, and the sample was subjected to further evaluation, including optical microscopy and chemical cleaning to verify corrosion progression.

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Fig. 4. Reference tags RSSI fluctuation over time alongside a conceptual corrosion progression curve of the working tags.