Fractographic analysis of tensile failures of aerospace grade composites

Kumar, M Suresh; Raghavendra, K; Venkataswamy, Magalapalaya Anjanappa; Ramachandra, Honnudike Venkateshwararao

doi:10.1590/s1516-14392012005000141

Cited by 42 publications

(27 citation statements)

References 20 publications

(20 reference statements)

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“…It is obvious that incorporating MWCNTs in epoxy matrix alters the failure mode of the GFRP composites. A typical broom-like failure of the GFRP composites was observed in the coupons fabricated using neat epoxy due to the weak interfacial bond between glass fibers and the epoxy matrix as reported by others [39][40][41]. However, the figure shows that incorporating 0.5 wt% and 1.0 wt% MWCNTs significantly limited the broom-like failure of the GFRP composites giving a sign of enhancing the cohesive strength of the epoxy nanocomposite matrix.…”

Section: Tensile Strengthsupporting

confidence: 61%

Improving Fatigue Performance of GFRP Composite Using Carbon Nanotubes

Genedy

Daghash

Soliman

et al. 2015

Fibers

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Glass fiber reinforced polymers (GFRP) have become a preferable material for reinforcing or strengthening reinforced concrete structures due to their corrosion resistance, high strength to weight ratio, and relatively low cost compared with carbon fiber reinforced polymers (CFRP). However, the limited fatigue life of GFRP hinders their use in infrastructure applications. For instance, the low fatigue life of GFRP caused design codes to impose stringent stress limits on GFRP that rendered their use non-economic under significant cyclic loads in bridges. In this paper, we demonstrate that the fatigue life of GFRP can be significantly improved by an order of magnitude by incorporating Multi-Wall Carbon Nanotubes (MWCNTs) during GFRP fabrication. GFRP coupons were fabricated and tested under static tension and cyclic tension with mean fatigue stress equal to 40% of the GFRP tensile strength. Microstructural investigations using scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy were used for further investigation of the effect of MWCNTs on the GFRP composite. The experimental results show the 0.5 wt% and the 1.0 wt% MWCNTs were able to improve the fatigue life of GFRP by 1143% and 986%, respectively, compared with neat GFRP.

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Section: Tensile Strengthsupporting

confidence: 61%

Improving Fatigue Performance of GFRP Composite Using Carbon Nanotubes

Genedy

Daghash

Soliman

et al. 2015

Fibers

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“…The chevron marking are facing toward the fracture point and is a good evidence to show the crack propagation region exhibits brittle fracture emanating from the crack origin. By referring to Kumara et al [26], composites displaying good interfacial bonding characteristics exhibit brittle fracture. The presence of chevron lines is helpful in identifying the failure origin and the crack propagation directions.…”

Section: Three Point Flexural -Brittleness Of Gelcoatmentioning

confidence: 99%

Effects of gelcoat thickness on mechanical properties of woven glass/polyester laminated composite

Yuhazri¹,

Amirhafizan²,

Nilson³

et al. 2018

J. MECH. ENG. SCI.

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In this study, effects of gelcoat thickness on the mechanical properties and interfacial bonding of woven glass/polyester laminated composite are investigated by using threepoint flexural test and tensile test. The composites had been applied at variance thickness of gelcoat layers (0.25, 0.3, 0.35, 0.4, 0.45, and 0.5mm) using hand lay-up method. Samples were measured in two techniques for the flexural test, i.e., coated surface facing the loads (concave) and bare surface facing the loads (convex). Since the coated surface was concavely bent, greatest increase of flexural strength that acquired 5fold of increase was shown by composite with 0.3 mm of gelcoat thickness for both measurements. The increasing of thickness to 0.35 mm and above deflated the rising percentage in flexural strength. This event was happened because of the gelcoat thickness ratio was greater than the matrix/reinforcement ratio. For tensile test, composite applied with gelcoat of 0.4 mm thickness exhibited the highest increase in strength. An increase of almost 38 % in tensile strength was recorded compared to the uncoated composite. Similarly, the increase in tensile strength reduced slightly when the gelcoat thickness was increased above 0.4 mm. The results demonstrate that the mechanical properties of the composite improve as the gelcoat thickness increases. However, the mechanical properties show no further improvement as the thickness is further increased above the optimum thickness.

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“…This procedure is useful because it can be used to optimize the composite processing and also to prevent other damages that can occur in the future. Thus, fractographic studies have been strongly disseminated and used not only in the area of metallic materials, but also in the polymeric composites reinforced with continuous fibers [45][46][47][48][49][50][51][52][53] .…”

Section: Introductionmentioning

confidence: 99%