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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3.3. Energy-absorption properties To adequately visualize the energy-absorption properties of the FRPSS under indentation load, it is necessary to superimpose the force and energy-displacement curves. In Fig 4, the load and energy absorption-displacement curves can be broadly categorized into three distinct regions (I, II, and III), with the force and energy curves denoted (_f) and (_e) respectively. In region I, at peak force F 1 , where the core crushing/face sheet penetration started has a corresponding energy value (E 1 ), while in region II, the max peak force (F max ) has a corresponding energy value of (E max ). As can be seen from Fig 4, the variation in E 1 and E max for GS samples due to seawater exposure was 34.6 % and 64 % respectively while CS dropped by 44.3 % and 9.4 % over the same period.

(a)

(b)

I

II

III

I

III

II

E max

E 1

E max

E max

E 1

E max

E 1

E 1

Fig. 4. Load and energy absorption-displacement curves of FRPSS; (a) GS (b) CS. note _f represent force, _e represent energy. A considerable decrease in the SEA of the samples after exposure to seawater was observed (Fig. 5) and this could be attributed to the localized deformation around the region of indentation, which was greater due to the reduction in bonding strength after the exposure.

Fig. 5. Normalized SEA of FRPSS.