Effect of Impactor Design on Unidirectional and Woven fiber Reinforced Composites

Ahmed, Payman Sahbah

doi:10.17656/sjes.10033

Cited by 6 publications

(8 citation statements)

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“…These failure mechanisms contribute to the amount of energy absorbed by the FML system, in which it is clearly can be seen that the woven fibre absorb more energy compared to unidirectional fibre during static indentation loading. Ahmed et al [14] also reported that the woven type of fibre resulted in minimum deformation and maximum force and energy. He concluded that woven type composites have good ability to absorb large energy, while unidirectional type of fibre showed low energy absorption [14].…”

Section: Quasi-static Indentation Test (Qsi)mentioning

confidence: 98%

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Woven and Unidirectional Glass-Aluminium Fibre Metal Laminates (FML): Quasi-Static Indentation Properties

Jumahat*,

Najib,

Sapiai

2019

IJRTE

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In this study, the effect of fibre arrangement and aluminium thin sheet on quasi-static indentation properties of fibre metal laminates (FML) based on glass fibre reinforced polymer composite (GFRP) and Aluminium (Al) was investigated. The woven and unidirectional types of glass fibre prepreg and 0.5mm, 1mm and 2 mm of Al sheet thickness were used in the fabrication of Glass fibre-Al FML systems. The GFRP and FML samples were fabricated using a combination of hand lay–up and hot press methods. Quasi-static indentation test was performed according to ASTM D6264. The results showed that the woven type of GFRP and FMLs exhibited the highest energy absorption as compared to those of unidirectional of GFRP and FMLs. It was observed that for the woven type specimens of GFRP and FMLs, the matrix cracking and fibre breakage/delamination triggered in weft and wrap direction, which showed diamond-shaped damage. While the damage surface of unidirectional GFRP and FMLs showed single axis orientation damage type that lateral with the direction of the fibre namely fibre splitting mechanism. The FML2 systems for both woven and unidirectional, that used 2mm thickness of Al, demonstrated the highest energy absorption when compared to the other FML systems. This shows that FMLs absorbed more energy when thicker Al sheet was used.

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Section: Quasi-static Indentation Test (Qsi)mentioning

confidence: 98%

“…Ahmed et al [14] also reported that the woven type of fibre resulted in minimum deformation and maximum force and energy. He concluded that woven type composites have good ability to absorb large energy, while unidirectional type of fibre showed low energy absorption [14].…”

Section: Quasi-static Indentation Test (Qsi)mentioning

confidence: 98%

Woven and Unidirectional Glass-Aluminium Fibre Metal Laminates (FML): Quasi-Static Indentation Properties

Jumahat*,

Najib,

Sapiai

2019

IJRTE

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“…The results revealed that 0.2 Wt.% of MWCNTs improve tensile properties, whereas 0.6 Wt.% of MWCNTs improve impact characteristics (Fadhil et al, 2016). Ahmed (2016) used different designs of the impactor in drop-weight impact test (bullet, cone and hemispherical) and investigated this effect on the impact properties of epoxy composites reinforced with unidirectional glass, unidirectional carbon, woven glass and hybrid woven (glass þ carbon) fibers. Results showed that changing the impactor design had no effect on the impact characteristics of composites reinforced with woven fiber, whereas it has a huge effect on unidirectional fiber-reinforced composites.…”

Section: Mmms 166mentioning

confidence: 99%

“…Results showed that changing the impactor design had no effect on the impact characteristics of composites reinforced with woven fiber, whereas it has a huge effect on unidirectional fiber-reinforced composites. Indentation and perforation were observed as impact damage behavior of woven composites while matrix cracking and splitting along the fiber direction and the fracture were for unidirectional fiber-reinforced composites (Ahmed, 2016). Others studied hybrid armor made of UHMWPE and soft structure panel to increase energy absorption (Liu et al, 2018).…”

Section: Mmms 166mentioning

confidence: 99%

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Abed

Ahmed

Oleiwi

et al. 2020

MMMS

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PurposeComposite laminates are considered one of the most popular damage-resistant materials when exposed to impact force in civil and military applications. In this study, a comparison of composites 12 and 20 layers of fabrics Kevlar and ultrahigh-molecular-weight poly ethylene (UHMWPE)-reinforced epoxy under low-velocity impacts represented by drop-weight impact and Izod pendulum impact has been done. During the Izod test, Kevlar-based composite showed damage at the composite center and fiber breakages. Whereas delamination was observed for UHMWPE reinforced epoxy (PE). The maximum impact strength was for Kevlar-reinforced epoxy (KE) and increases with the number of laminates. Drop-weight impact test showed the highest absorbed energy for (KE) composites. The results revealed that different behavior during the impact test for composites belongs to the impact mechanism in each test.Design/methodology/approachAramid 1414 Kevlar 49 and UHMWPE woven fabrics were purchased from Yixing Huaheng High-Performance Fiber Textile Co. Ltd, with specifications listed in Table 1. Epoxy resin (Sikafloor-156) is supplied from Sika AG. Sikafloor-156 is a two-part, low-viscosity, solvent-free epoxy resin, with compressive strength ∼95 N/mm², flexural strength ∼30 N/mm² and shore D hardness 83 (seven days). The mixture ratio of A/B was one-third volume ratio. Two types of laminated composites with different layers 12 and 20 were prepared by hand layup: Kevlar–epoxy and UHMWPE–epoxy composites as shown in Figure 1. Mechanical pressure was applied to remove bubbles and excess resin for 24 h. The composites were left in room temperature for seven days, and then composite plates were cut for the desired dimensions. Low-velocity impact testing, drop-weight impact, drop tower impact system INSTRON CEAST 9350 (see Figure 2) was facilitated to investigate impact resistance of composites according to ASTM D7137M (Test Method for Compressive, 2005). Low-velocity impact tests have been performed at room temperature for composite with dimensions 10 × 15 cm2 utilizing a drop tower (steel indenter diameter 19.85 mm as shown in Figure 3), height (800 mm), drop mass (5 kg) and speed (3.96 m/s). Special impact equipment consisting of vertically falling impactor was used in the test. The energy is obtained from Drop tower impact systems, (2009) E = ½ mv2 (2.1). The relationship between force–time, deformation–time and energy–time and deformation was obtained. Energy–deformation and force–deformation relationships were also obtained. The depth of penetration and the radius of impactor traces were recorded. Izod pendulum impact test of plastics was applied according to ASTM D256 (Test Method for Compressive, 2005). Absorbed energy was recorded to compute the impact strength of the specimen. The specimen before the test is shown in Figure 4.FindingsIn order to investigate two types of impact: drop-weight impact and Izod impact on damage resistance of composites, the two tests were done. Drop-weight impact is dropping a known weight and height in a vertical direction with free fall, absorbed energy can be calculated. Izod impact measures the energy required to break a specimen by striking a specific size bar with a pendulum (Test Method for Compressive, 2005; Test Methods for Determining, 2018). The results obtained with the impact test are presented. Figure 5 shows the histogram bars of impact strength of composites. It can be noticed that Kevlar–epoxy (KE) composites give higher energy strength than UHMWPE–epoxy (PE) in 12 and 20 plies. The increasing percentage is about 18.5 and 5.7%. It can be observed in Figure 6 that samples are not destructed completely due to fiber continuity. Also, the delamination occurs obviously for UHMWPE–epoxy more than for Kevlar-based composite, which may due to weak binding between UHMWPE with an epoxy relative with Kevlar.Practical implicationsThe force–time curves for Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites with 12 and 20 plies are illustrated respectively in Figure 7. The contact duration between indenter and composite surface is repented by the force–time curves, so the maximum force reaches with certain displacement. It can be seen that maximum force was (13,209, 18,734.9, 23,271.07 and 19,825.38 N) at the time (3.97, 4.43, 3.791 and 4.198 ms) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. The sharp peaks of KE composite are due to the lower ductility of Kevlar compared with UHMWPE. These results agree with the results of Ahmed et al. (2016). Kevlar-based composites (KE) showed lower impact force and crack propagates in the matrix with fast fiber breakage compared with PE composites, whereas the latter did not suffer from fabric breakage in 12 and 20 plies any more (see Figure 8). Figure 9 illustrates force–deformation curves, for 12 and 20 plies of Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites. Curve's slop is considered the specimen's stiffness and the maximum displacement. To investigate the impact behavior of the four different composites, the comparison was made among the relative force–deformation curves. The maximum displacement was 5.119, 3.443, 1.173 and 1.17 mm for 12KE, 12 PE, 20 KE and 20 PE, respectively. It seems that UHMWPE-based composite (PE) presents lower deformation than Kevlar-based composites (KE) at a same number of laminates, although the maximum displacement is for 12 PE and 12 KE (see Figure 8). Kevlar-based composites (KE) showed more damage than UHMWPE-based composite (PE), so the maximum displacement is always higher for KE specimens with maximum indenter trace diameter (D∼11.27 mm). The onset of cracks begins along fibers on the impacted side for 20 KE and 20 PE specimens with lower indenter trace (D∼5.42 and 5.96 mm), respectively (see Table 2). These results refer to the lower stiffness of KE composites (see the slope of the curve) relative to PE composites. This result agreed with (Vieille et al., 2013) when they found that the theoretical stiffness of laminated composite during drop-weight impact depends significantly on fiber nature (Fadhil, 2013). The matrix cracking is the first type of damage that may not change stiffness of composites overall. Material stiffness changes due to the stress concentration represented by matrix cracks, delamination and fiber breakage (Hancox, 2000). Briefly, the histogram (see Figure 10) showed that the best impact behavior was for 20 KE, highest impact force with lower deformation, indenter trace diameter and contact time. Absorbed energy–time and absorbed energy–deformation curves for composites are shown in Figures 11 and 12, respectively. The maximum absorbed energy was (36.313, 29.952, 9.783 and 6.928 J) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. Test period time is only 8 ms, but the time in which composites reached maximum absorbed energy was (4.413, 3.636, 2.394 and 2.408 ms). The maximum absorbed energy was for 12 KE with lower rebound energy because part of kinetic energy transferred to potential energy kept in the composite as material damage (see Figures 3 and 4). This composite absorbs more energy as material damage which kept as potential energy. Whereas other composites 12 PE, 20 PE and 20 KE showed less damage, lower absorbed energy and higher rebound energy, which appeared in different peak behavior as the negative value of energy. Also from the absorbed energy–time curves, it had been noticed significantly the maximum contact time of indenter with composite was 4.413 ms for 12 KE, which exhibits higher deformation (5.119 mm), whereas other composites 12 PE, 20 KE and 20 PE showed less damage, contact time and deformation as (3.443, 1.173, 1.17 mm), respectively.Originality/valueThe main goal of the current study is to evaluate the performances of armor composite made off of Kevlar and UHMWPE fabrics reinforced epoxy thermosetting resin under the low-velocity impact. Several plates of composites were prepared by hand layup. Izod and drop-weight impact tests were facilitated to get an indication about the absorbed energy and strength of the armors.

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“…Payman S. A. [9] studied the effect of impactor design on the impact properties of epoxy composites reinforced with unidirectional glass, unidirectional carbon, woven glass and hybrid woven (glass + carbon) fibers. This research shows that changing the impactor design have no effect on impact properties of woven reinforced composites while it has a significant effect on unidirectional fiber reinforced composites, and glass fiber reinforced composites have a better impact property than carbon reinforced composites.…”

Section: Introductionmentioning

confidence: 99%

Effect of reinforcement material on impact properties of epoxy

Fadhil

Ahmed

Kamal

2017

KJAR

Self Cite

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Impact characteristics of Epoxy matrix composites is investigated by impact machine. Four different types of reinforcement are used in the experimental works: type one: 1.9wt% steel fiber, 1.9wt% carbon fiber,1.9 wt% carbon nanotube, 1.9 wt% woven carbon fiber. This work shows that reinforcing epoxy with (1.9 wt% of woven carbon fiber) improves the impact properties where energy, force and deformation values of impact test for this composite were 18.4J, 3580.59 N and 18 mm respectively while for epoxy were 2.927 J, 921.849 N and 18.413 mm respectively.

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Effect of Impactor Design on Unidirectional and Woven fiber Reinforced Composites

Cited by 6 publications

References 0 publications

Woven and Unidirectional Glass-Aluminium Fibre Metal Laminates (FML): Quasi-Static Indentation Properties

Woven and Unidirectional Glass-Aluminium Fibre Metal Laminates (FML): Quasi-Static Indentation Properties

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Effect of reinforcement material on impact properties of epoxy

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