Three-dimensional features of void morphology in resin transfer molded composites

Hamidi, Youssef K.; Aktas, Levent; Altan, M. Cengiz

doi:10.1016/j.compscitech.2005.01.001

Cited by 74 publications

(69 citation statements)

References 27 publications

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“…This is also in agreement with the experimental results of Hamidi et al [21], where radial injections in a circular mold were conducted, founding that the most of voids were formed at the rear edge of the tows with respect to the flow direction, both inside the tow and in the transition tow-channel. Other numerical works, [24,25,43,54], have also predicted the void formation at similar locations.…”

Section: Influence Of the Jump Stress Coefficientsupporting

confidence: 81%

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Stokes–Brinkman formulation for prediction of void formation in dual-scale fibrous reinforcements: a BEM/DR-BEM simulation

et al. 2017

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A numerical study of voids formation in dualscale fibrous reinforcements is presented. Flow fields in channels (Stokes) and tows (Brinkman) capillary ratio, jump stress coefficient and two formulations (Stokes-Brinkman and Stokes-Darcy) on the filling process, void formation and void characterization. Filling times, fluid front shapes, void size and shape, time and space evolution of the saturation, are influenced by these parameters, but voids location is not.

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Section: Influence Of the Jump Stress Coefficientsupporting

confidence: 81%

“…In general, the void shapes obtained in this work are physically consistent with some experimental works. For instance, Hamidi et al [20,21] studied the void morphology in the Resin Transfer Molding process (RTM), observing different void shapes inside the bundles:…”

Section: Influence Of the Jump Stress Coefficientmentioning

confidence: 99%

Stokes–Brinkman formulation for prediction of void formation in dual-scale fibrous reinforcements: a BEM/DR-BEM simulation

et al. 2017

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“…Void contents in the composites containing nanoclay do not seem to show clear radial trends. However, radial void contents of the composite molded without nanoclay appear to follow predictions of the capillary analysis [17][18][19][20][21][22]37,38]. Because the mold filling is performed at a constant injection rate, the fluid front velocity decreases with increasing distance from injection gate.…”

Section: Effect Of Nanoclay Content On Radial Voidage Variationmentioning

confidence: 93%

Effect of Nanoclay Content on Void Morphology in Resin Transfer Molded Composites

Hamidi

Aktas

Altan

2008

Journal of Thermoplastic Composite Materials

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Effects of nanoclay content on morphology and spatial distribution of voids in resin transfer molded nanoclay/E-glass/epoxy composite disks are investigated. Closite Õ 25A nanoclay loads of 2, 5, and 10 wt% are mixed by sonication with a low-viscosity epoxy resin prior to filling the mold cavity containing 13.6% E-glass preform by volume. A disk without nanoclay is also molded. Once the molded composites are cured, voids on radial composite samples are evaluated via microscopic image analysis. The addition of nanoclay is found to result in a significant increase in the apparent viscosity of the clay-epoxy mixture, thus increasing the molding pressure. Void occurrence is observed to increase considerably with increasing nanoclay content, from 2.1% in the composite without nanoclay to 5.1 and 8.3% in the composites molded with 5 and 10 wt% nanoclay, respectively. However, the composite with 2 wt% nanoclay yields the lowest void content of 0.7%. Voids are observed to be, in average, smaller after the addition of nanoclay at all nanoclay concentrations. Presence of nanoclay in the impregnating resin induces at least 60% reduction in voids located inside fiber tows, which are trapped by the fluid front motion during impregnation. Irregularly shaped voids are also observed to decrease with increasing nanoclay content. A nonuniform void content and morphology is observed radially, which seems to be affected by the flow kinematics as well as possible breakdown and filtration of clay clusters.

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“…The intent in such simulations is to place a vent in a region where the resin arrives last, to ensure no voids remain [18]. However, in addition to macrovoids that can be visually seen, another concern in manufacturing with LCM is microvoids, which are micron size regions devoid of resin within a fiber tow or in the vicinity [4,[19][20][21][22][23]. These voids cannot be seen by visual inspection, but can be detected by non-destructive testing such as ultrasound [24,25], if they are larger than 1 lm, or by destructive testing, where samples are machined and evaluated under a microscope [25,26], as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Analytic characterization of the permeability of dual-scale fibrous porous media

Zhou

Kuentzer

Šimáček

et al. 2006

Composites Science and Technology

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Three-dimensional features of void morphology in resin transfer molded composites

Cited by 74 publications

References 27 publications

Stokes–Brinkman formulation for prediction of void formation in dual-scale fibrous reinforcements: a BEM/DR-BEM simulation

Stokes–Brinkman formulation for prediction of void formation in dual-scale fibrous reinforcements: a BEM/DR-BEM simulation

Effect of Nanoclay Content on Void Morphology in Resin Transfer Molded Composites

Analytic characterization of the permeability of dual-scale fibrous porous media

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