On the Use of Darcy Permeability in Sheared Fabrics

Dungan, F. D.; Senoguz, M. T.; Sastry, Ann Marie; Faillaci, D. A.

doi:10.1177/073168449901800507

Cited by 17 publications

(5 citation statements)

References 11 publications

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“…The permeability generally tends to be lower in the transverse direction. 14,24,28,33 In fact, in the y-direction, pores are smaller resulting in a greater resistance to the flow which is not the case in x-direction.…”

Section: Determination Of Materials Properties In In-plane Impregnationmentioning

confidence: 92%

Investigation of capillary impregnation for permeability prediction of fibrous reinforcements

Koubaa

Burtin

Corre

2015

Journal of Composite Materials

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In thermoplastic pultrusion process, unidirectional glass fibre bundles are very often used as reinforcement. This study was motivated by the industrial requirement to evolve from low viscosity thermoset resin processes to high viscosity thermoplastic polymers. The key parameters to control the impregnation process are the permeability of the fibrous reinforcement and the capillary pressure. The current study's objectives are threefold: (1) study the fibres arrangement by X-ray tomography, (2) determine the longitudinal and transversal permeabilities as well as capillary pressure to use them as input parameters of impregnation process in pultrusion and (3) carry out sensitivity analyses of the permeability measurements to the perturbation of fibre structure. To reach these purposes, two theoretical models were used to determine both axial and transversal tow permeability. The axial impregnation of aligned fibres was described by Washburn equation applied to 1D infiltration into the bundles. The in-plane impregnation was described by Darcy's law. The elliptical equation for highly anisotropic medium was resolved. Results show that permeability measurements are subjected to large variations, caused by perturbation of the fibre architecture during experiments. Besides, it was shown that the tensile force applied on fibres during pultrusion has a great effect on impregnation. Indeed, the permeability increases with the applied tension.

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Section: Determination Of Materials Properties In In-plane Impregnationmentioning

confidence: 92%

Investigation of capillary impregnation for permeability prediction of fibrous reinforcements

Koubaa

Burtin

Corre

2015

Journal of Composite Materials

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“…Therefore, the pressure gradient between both areas becomes a driving force for infusing liquid resin into the dry preform and eventually to the outlet. This is governed by Darcy's law [27][28][29]. According to formulas (1) and ( 2), the larger the differential pressure and the higher the preform permeability, the faster the flow velocity during the infusion process.…”

Section: Flow Simulationmentioning

confidence: 99%

Improvement of impregnation quality on out-of-autoclave processed CFRP aircraft wing spar through resin flow simulation

Park

et al. 2021

Funct. Compos. Struct.

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Vacuum-assisted resin transfer molding (VaRTM) is becoming one of the most robust alternatives for autoclave processes. VaRTM, which applies the resin injection method in a vacuum environment, generally uses fiber reinforcement and a polymer matrix separately in the process. The VaRTM is mainly dominated by the characteristics of constituent materials, such as preform permeability and resin viscosity. Among them, process design with the arrangement of resin inlet/outlet locations is closely related to process defects, and inappropriate inlet/outlet layouts cause voids, etc, which has a decisive effect on quality degradation. Therefore, in this study, a highly curved and twisted spar structure was fabricated by the VaRTM, and both flow simulations using Programs for Applied Mechanics–Resin Transfer Molding software and experimental test parts built with three different inlet/outlet line conditions were performed and compared to predict and improve impregnation quality. There was good agreement between the simulation and built test specimen for the three cases that the shorter inlet and outlet length resulted in improved impregnation quality. It was verified that impregnation and inner quality could be improved through flow simulation analysis during the VaRTM process.

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“…However, several conclusions from studies on 0/90 sheared fabrics [3][4][5] can be applied to the permeability of braided fabrics. The increase or decrease of the braiding angle from AE45 reduces the yarns spacing and therefore, the permeability decreases [5]. Also, the alignment of the fibers with the injection direction increases the permeability [3].…”

Section: Introductionmentioning

confidence: 97%

“…The open literature shows that the permeability of a wide range of reinforcements has been studied, but the evaluation of braided fabrics is almost nonexistent [2]. However, several conclusions from studies on 0/90 sheared fabrics [3][4][5] can be applied to the permeability of braided fabrics. The increase or decrease of the braiding angle from AE45 reduces the yarns spacing and therefore, the permeability decreases [5].…”

Section: Introductionmentioning

confidence: 98%

Evaluation of the Physical and Mechanical Properties of Braided Fabrics and their Composites

Charlebois

Boukhili

Zebdi

et al. 2005

Journal of Reinforced Plastics and Composites

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This study aims to evaluate the permeability and the basic mechanical properties of braided fabrics intended for hollow composites to be manufactured by resin infusion processes. A simple procedure has been devised to obtain flat specimens for the required permeability and mechanical tests. Permeability measurements have been performed on 2-D biaxially braided glass fabrics at three braiding angles. The change of the braiding angle affects the fiber volume fraction, which in turn affects the permeability. Tension, compression, and shear tests have also been conducted on unidirectional (UD) and braided glass-epoxy composites. From the experimental UD properties, the lamination theory (LT) has been used to predict the properties of angle ply (AE) laminates equivalent to the braided composites tested. From the comparison of the predicted and experimental results, the effects of the fibers' intertwining and undulation on the mechanical properties have been derived. The undulation of the fibers is responsible for the compression strength reduction, mainly at low braiding angles, but has no effect on the tensile strength. For all angles, the braided composites have a higher modulus than the predicted angle ply laminates. The Iosipescu shear method is not suitable for the characterization of composites containing braided fabrics because of their high shear stiffness and strength.

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On the Use of Darcy Permeability in Sheared Fabrics

Cited by 17 publications

References 11 publications

Investigation of capillary impregnation for permeability prediction of fibrous reinforcements

Investigation of capillary impregnation for permeability prediction of fibrous reinforcements

Improvement of impregnation quality on out-of-autoclave processed CFRP aircraft wing spar through resin flow simulation

Evaluation of the Physical and Mechanical Properties of Braided Fabrics and their Composites

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