PSI - Issue 64

Nikhil Holsamudrkar et al. / Procedia Structural Integrity 64 (2024) 815–821 Holsamudrkar Nikhil et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Interestingly, the event rate shows minimal variation from phase I to phase II due to improved load distribution, resulting in less damage to both the FRCM system and concrete. Throughout phase III, the average frequency remains relatively reduced, hovering around 60 kHz, indicating more damage to the matrix component than the fabric. Historical indices exhibit peaks corresponding to significant events observed during the test. The enhanced load distribution of the strengthening system leads to Phase II displaying events with more intensity than Phase I. Analysis of the RA-AF plot reveals that 91.02% of hits are dominated by tensile mode, coinciding with the observed fabric rupture failure.

Fig. 4. Variation of (a) Cumulative AE hits for different channels wrt time, (b) Average frequency, RA value, Event rate wrt time, (c) Historic index, Cumulative signal strength wrt time, and (d) AF-RA scatter plot for the specimen S1-NA

3.2. Specimen S1-NA This specimen is reinforced using a conventional S1 methodology without anchorage, achieving an ultimate load of 150.1 kN. Fig 4 provides a comprehensive overview of all the results obtained. The load-displacement curve reveals three distinct phases, marked by changes in the slope of both AE cumulative hits and the CSS curve. Notably, a sudden increase in the event rate during the second phase indicates FRCM damage activity. The average frequency gradually decreases from phase I to phase III while the RA value gradually increases. Historic indexes highlight larger peaks during phase II compared to the other two specimens, suggesting more significant damage to the FRCM component due to debonding. Analysis of the RA-AF plot reveals that tensile forces dominate 80.69% of the damage. Additionally, shear activity for this specimen appears to be higher than that observed in other specimens, indicating fiber-matrix debonding. 4. Conclusions The current study includes AE-based health monitoring of RC beams strengthened with FRCM composites prepared using different methodologies. All the methods show comparable load-displacement behavior, S3-AN being the