Damage Behaviors and Compressive Strength of Toughened CFRP Laminates with Thin Plies Subjected to Transverse Impact Loadings

Yokozeki, Tomohiro; Aoki, Yoshio; Ogasawara, Toshio

doi:10.2322/jjsass.55.388

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…The impact resistance of CFRPs must be improved to ensure the safety and reliability of structures. Yokozeki et al [8] have suggested that the impact resistance of CFRPs by out-of-plane impact load was improved by using the toughened CFRP laminated with thin plies. Yamada et al [9] have also proposed that the metal layers insertion in thin-ply composite laminates was improved Compressive after impact (CAI) strength by inhibiting the fiber break.…”

Section: Introductionmentioning

confidence: 99%

Effect of sub-micron glass fiber addition on CAI strength of UD-CFRP

Murayama¹,

Obunai²,

Okubo³

2022

Int. J. CMEM

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The purpose of this study is to investigate the effect of the addition of sub-micron glass fiber (sGF) into the matrix of carbon fiber reinforced plastics (CFRP) on the impact energy absorption and Compressive after impact (CAI) strength of it. The unidirectional (UD)-CFRP was fabricated with UD-carbon fiber fabric and thermoset epoxy resin modified by adding 0.3wt% of sGF. For comparison, UD-CFRP made with the neat epoxy resin was also prepared. The impact energy absorption under out-of-plane impact was measured by using falling-type impact testing equipment. In this study, the applied impact energy was 3, 5, 7, 10, and 20 J by changing the mass of the drop weight. After the tests, a compressive load was also applied to the specimen to investigate the CAI strength of UD-CFRP. Test results showed that when the applied impact energy was relatively low (3 and 5 J), the energy absorption of the modified UD-CFRP was slightly improved, compared to that of the neat UD-CFRP. The projection areas of internal damages of UD-CFRP after the drop weight test were also decreased by the sGF addition. However, when the applied impact energy exceeds 7 J, there were no differences in the energy absorption of UD-CFRP even if the sGF was added to the matrix. The scanning electron microscope (SEM) observations of the fractured surface of UD-CFRP after the drop weight test suggested that the adhesion between carbon fiber and matrix resin was improved by the addition of sGF when the low impact energy was applied. The interlaminar shear strength of the modified UD-CFRP was also improved. The CAI strength of modified UD-CFRP was improved when the applied impact energy was relatively low. However, when the applied impact energy exceeds 7 J, the CAI strength of UD-CFRP was degraded by adding sGF. Therefore, when low impact loading was applied, the addition of sGF into UD-CFRP was effective to improve CAI strength.

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Section: Introductionmentioning

confidence: 99%

Effect of sub-micron glass fiber addition on CAI strength of UD-CFRP

Murayama¹,

Obunai²,

Okubo³

2022

Int. J. CMEM

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show abstract

“…The use of thin-ply prepreg was proved to have distinct effects on laminates' strength. In a study by Yokozeki et al (2007), the use of thin-ply prepreg in quasi-isotropic laminates can improve compressive-after-impact (CAI) strength of the laminates compared to prepregs with conventional thickness. They also showed that the CFRP laminates which have thin-ply prepregs at the outer surface with conventional prepregs as inner plies cured together exhibited the highest CAI strength among stacking combinations they tested.…”

Section: Introductionmentioning

confidence: 99%