An experimental method for characterizing unsaturated 1D flow in tubular braided preforms during bladder‐assisted resin transfer molding

Schillfahrt, Christian; Fauster, Ewald; Schledjewski, Ralf

doi:10.1002/pc.24585

Cited by 2 publications

(2 citation statements)

References 51 publications

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“…The material permeability data are shown in table 2. The permeability of each material was experimentally obtained based on the flow-front velocity measurement using permeability measurement device as shown in figure 4 [36][37][38]. The manufacturer's technical data was referred for the resin viscosity value as shown in figure 5.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…The most common model to describe fluid flow through a porous material is Darcy's law; it correlates the volume‐averaged flow rate ν with permeability K , pressure gradient ∇P , and viscosity η – see Equation (). [ 10,131,205–207 ] Viscosity can be defined as the fluid's resistance to flow. [ 208 ] A permeability equation based on the research of Kozeny and Carman [ 184,209–211 ] (Equation ()) allows to estimate the permeability in longitudinal direction via the fiber volume ratio ( e F ), the fiber radius ( r F ), and the Kozeny constant k , a geometric factor.

υ = - \frac{K \nabla P}{η},

K = \frac{{r_{F}}^{2} {(1 - e_{F})}^{3}}{4 k {e_{F}}^{2}} .

…”

Section: Main Effects On the Roving During Processingmentioning

confidence: 99%

An overview on current manufacturing technologies: Processing continuous rovings impregnated with thermoset resin

et al. 2021

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The demand for products made of fiber‐reinforced polymer composites (FRPC) is constantly growing. These lightweight products are characterized by high stiffness, high tensile strength, and high service life. FRPC processes that employ thermoset‐impregnated continuous rovings are easily automated and provide the products with the highest unidirectional tensile strength. A critical disadvantage of continuous fiber‐reinforced polymers is caused by relatively high production costs. Among others, three main factors contribute to these production costs: (1) material costs, especially when carbon fibers are used, (2) costs for manufacturing semi‐finished products, such as textiles or preimpregnated fabrics, and (3) costs for waste occurring along the entire chain of process steps. In this context, one group of processes shows outstanding characteristics: processes in which rovings are in situ impregnated with a thermoset resin and then directly processed. Wet filament winding and pultrusion are the most popular but not the only representatives of this group. For all these processes, in situ impregnation is the key element, and various technologies have been developed for this purpose, each with its own unique fluid‐mechanical effects on rovings. A fundamental understanding of these effects is crucial to achieve products of the utmost quality. The paper at hand provides an overview of manufacturing processes that employ in situ impregnation of continuous rovings, specifically focusing on impregnation technologies. On this basis, phenomenological models describing the effects on the rovings during processing (impregnation, tension, and spreading) are reviewed.

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An experimental method for characterizing unsaturated 1D flow in tubular braided preforms during bladder‐assisted resin transfer molding

Cited by 2 publications

References 51 publications

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

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

An overview on current manufacturing technologies: Processing continuous rovings impregnated with thermoset resin

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