PSI - Issue 54

Norman Osa-uwagboe et al. / Procedia Structural Integrity 54 (2024) 44–51 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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3.4. Damage Charaterization A post-mortem analysis of the damage region indicated that the seawater degradation resulted in an increase in the damage region, which could be due to the reduction in strength of the specimen and, therefore, a decline in damage resistance of the composites. Apparently, the damaged area increased by 26.7 % and 34.1 % for the GS and CS specimen after seawater exposure respectively. Thus, FRPSSs subjected to seawater exposure are prone to more severe damage from out-of-plane loading.

Fig. 6. Damaged area of FRPSS.

In terms of the macroscale damage morphology, the X- ray μ -CT results of GS_16 and CS_16 (Fig 7a and 7b), demonstrated that both samples had similar primary failure mechanisms which included fiber breakage, delamination, core failure, and core/face sheet debonding. At a microscale level, the SEM images (Fig 8) indicate that fibre breakage, fibre/matrix interface, delamination, and fibre pull-outs were the damage sequences for both samples. The results from this study provide details needed in an ongoing examination of the multiscale damage characterization of sandwich structures with foam cores exposed to the effects of salinity.