Measurement System for On-Line Compaction Monitoring of Textile Reaction to Out-of-Plane Impregnation

Dry fiber placement (DFP) is a technology which enables outstandingly high mechanical performance of composite parts as preform structures with load-related fiber orientations can be created with minimum of fiber crimp. Furthermore, DFP has high cost-saving potential due to minimum material wastage during production. Recently, the efficiency has been further improved using an online binder application system, allowing the direct usage of untreated rovings instead of pre-designed rovings with binder applied by the manufacturer. Nevertheless, the poor impregnation behavior of DFP-preforms during liquid composite molding processing methods remains a main challenge. Encouraging an out-of-plane impregnation, e.g. by using a vacuum-assisted or compression resin transfer molding process, reduces the flow length within the preform and is a first step toward reducing cycle times. However, further improvements are required in order to apply DFP-preforming methods in serial production.Within this study influences on the out-of-plane permeability of DFP-preforms were investigated. The considered parameters were related to the material (e.g. binder amount) as well as the layup process and subsequent process steps.

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“…Out-of-plane permeability values were determined following the saturated measurement principle 36 as visualized in Fig. 4.…”

Section: Methodsmentioning

confidence: 99%

Maximizing the out-of-plane-permeability of preforms manufactured by dry fiber placement

Rimmel

Becker

Mitscháng

2016

Advanced Manufacturing: Polymer & Composites Science

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“…Thus, measurements of only three distinct scalar coefficients is required, which can be done according to existing procedures reported in the literature [13][14][15][16][17][18][19][20][21]. A further simplification is possible: as the thickness of the reinforcement is small compared to its length and width, the problem can be assumed to be 2D.…”

Section: Methods Used For Materials Properties Characterizationmentioning

confidence: 99%

“…Most of them evaluate the in-plane permeability [13,14], concluding that radial flow (liquid injected from transverse direction at well-defined locations to evaluate 2D permeability) and linear flow (liquid injected from one end of the composite preform to evaluate 1D permeability) experiments give consistent results. The through-the-thickness permeability is more complex to determine [15][16][17][18][19][20][21] and is usually neglected because of the small thicknesses of the preforms.…”

Section: Introductionmentioning

confidence: 99%

Material Characterization for Reliable Resin Transfer Molding Process Simulation

et al. 2020

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Resin transfer molding (RTM) technologies are widely used in automotive, marine, and aerospace applications. The need to evaluate the impact of design and production critical choices, also in terms of final costs, leads to the wider use of numerical simulation in the preliminary phase of component development. The main issue for accurate RTM analysis is the reliable characterization of the involved materials. The aim of this paper is to present a validated methodology for material characterization to be implemented and introduce data elaboration in the ESI PAM-RTM software. Experimental campaigns for reinforcement permeabilities and resin viscosity measurement are presented and discussed. Finally, the obtained data are implemented in the software and then compared to experimental results in order to validate the described methodology.

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“…Klunker et al [9] used experimental setups with three slightly different injection and data acquisition systems to study the permeability of fibrous reinforcements for different injection pressures. Becker and Mitschang [10] built a measurement unit to simultaneously monitor compaction and measure the transverse permeability. Without using stacks of fabric layers like in other investigations, Drapier et al [11] designed a system with fewer fabric plies to study the influence of stitching density on permeability.…”

mentioning

confidence: 99%

“…Besides nesting, the transverse permeability of fabrics can also be affected by other factors, such as the deformation of fiber tows resulting from flow-induced compaction, [9,20,21] reinforcement distortions, [22,23] and dual-scale flow. [24][25][26][27][28] Affected by these factors and also the intrinsic features of different fabrics, such as the material and the woven pattern, the range of saturated transverse permeability can be very large, which generally varies from 10 −10 m 2 ( [14,18,[29][30][31] ), 10 −11 m 2 ( [12,13,19,32] ) to 10 −12 m 2 or even lower ( [9][10][11]20,33] ). No standard procedure has yet been proven to measure the saturated transverse permeability of fibrous reinforcements.…”

mentioning

confidence: 99%

Numerical and experimental investigation of saturated transverse permeability of 2D woven glass fabrics based on material twins

Huang

Causse

et al. 2019

Polymer Composites

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The transverse permeability of fibrous reinforcement is one of the critical parameters that govern fabrication efficiency and production quality in several liquid composite molding process variants devised to achieve transverse impregnation of fibrous reinforcements. It is difficult to precisely measure and predict the transverse permeability, because it is simultaneously affected by diverse factors, for example, the geometric features of the test mold, nesting between fabric layers, and flow‐induced compaction of the fiber bed. In this article, the saturated transverse permeability of 2D woven glass fabrics is investigated using information provided by mesostructural geometric models reproducing the real textile architecture. These models are created by micro‐CT aided geometric modeling, a recently proposed technique to analyze three‐dimensional images obtained by X‐ray microtomography. They are called “material twins” because they reproduce with assessed accuracy the geometrical configuration of the textile preform, are representative of material variability, and allow performing numerical simulations of flow or mechanical properties. Computer simulations of steady state transverse flows in material twins were carried out to evaluate the transverse permeability and compared to experiments. Issues concerning material variability due to nesting and the accuracy of transverse permeability measurements were considered and discussed. A good agreement was obtained between numerical and experimental values of transverse permeability. Both approaches show a significant influence of the number of layers considered, which can be explained by nesting between adjacent plies. Numerical simulations also illustrate how nesting significantly affects material variability.

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Measurement System for On-Line Compaction Monitoring of Textile Reaction to Out-of-Plane Impregnation

Cited by 10 publications

References 19 publications

Maximizing the out-of-plane-permeability of preforms manufactured by dry fiber placement

Maximizing the out-of-plane-permeability of preforms manufactured by dry fiber placement

Material Characterization for Reliable Resin Transfer Molding Process Simulation

Numerical and experimental investigation of saturated transverse permeability of 2D woven glass fabrics based on material twins

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