Modeling and simulation of voids and saturation in liquid composite molding processes

Park, Chung; Lebel, Aurélie; Saouab, Abdelghani; Bréard, Joël; Lee, Woo Il

doi:10.1016/j.compositesa.2011.02.005

Cited by 170 publications

(142 citation statements)

References 34 publications

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“…Knowing the flow volume and the transverse bundle width, the impregnation time ∆T bundle of the transverse bundle can be determined by Equations (19) and (20): (19) where (20) Here w bundle is the width of the transverse bundle, and ubundle can be calculated using Equation (1). From Equations (18) and (19), the total inter-bundle impregnation time ∆T total can be obtained (Equation (21)): (21) Assuming the regularity and continuity of the unit cell, the mean value of the void fraction V v of the unit structure can be determined by Equation (22) [22]: (22) where Φ is the macroscopic porosity of the fabric obtained from the ratio of the inter-bundle domain to the whole fabric area. The macroscopic porosity is obtained by measuring the ratio occupied by inter-bundle cavities by analyzing images of the fabric taken from above.…”

Section: Inter-bundle Impregnation Path and Void Formationmentioning

confidence: 99%

“…An intra-bundle resin flow velocity for each bundle (warp or weft) is defined by Equation (1), which is based on the Darcy's law with an additional term for the capillary pressure gradient [21,25]:…”

Section: Intra-bundle Impregnation Pathmentioning

confidence: 99%

“…Unlike the macro-scale voids, meso-scale and microscale voids are caused by the unevenness of the fabric microstructure, which depends on the capillary number, and numerical models for predicting the void fraction values have been developed in previous studies [13,21,22]. Park et al [21] proposed a method for predicting the meso-scale and micro-scale void fractions by calculating the intra-bundle and interbundle flow velocities. Matsuzaki et al [23] presented a model for predicting the meso-scale void-fraction in the warp and weft directions of anisotropically woven fabrics.…”

Section: Introductionmentioning

confidence: 99%

“…To prevent the appearance of macro-scale voids, various simulations were performed to determine the optimal gate location [17][18][19][20]. Unlike the macro-scale voids, meso-scale and microscale voids are caused by the unevenness of the fabric microstructure, which depends on the capillary number, and numerical models for predicting the void fraction values have been developed in previous studies [13,21,22]. Park et al [21] proposed a method for predicting the meso-scale and micro-scale void fractions by calculating the intra-bundle and interbundle flow velocities.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Analytical prediction of void distribution and a minimum-void angle in anisotropic fabrics for radial injection resin transfer molding

Matsuzaki¹,

Naito²,

Seto³

et al. 2016

Express Polym. Lett.

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Abstract. 2D radial injection vacuum-assisted resin transfer molding experiments were performed using anisotropic plainwoven fabrics to determine the void distribution and the relationship between the void fraction and the resin flow velocity at arbitrary resin impregnation angles. The obtained void fraction values vary with the impregnation angle and velocity, while void formation is very difficult at the minimum-void angle oriented in neither the warp nor the weft direction. Moreover, the impregnation in the fabric microscopic structure is characterized by two patterns separated at the minimum-void angle. Based on the experimental results, a mathematical model for predicting the void fraction value at arbitrary impregnation angles and velocities and for calculating the minimum-void angle was developed. A comparison of the model predictions with the experimental results revealed a good agreement between them.

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Section: Inter-bundle Impregnation Path and Void Formationmentioning

confidence: 99%

Section: Intra-bundle Impregnation Pathmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analytical prediction of void distribution and a minimum-void angle in anisotropic fabrics for radial injection resin transfer molding

Matsuzaki¹,

Naito²,

Seto³

et al. 2016

Express Polym. Lett.

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show abstract

“…Current attempts are being made to couple void formation and void movement models to be able to predict the final distribution [20,21]. These models would assist in RTM process optimisation for high-performance composites, however, they are limited by (i) the difficulty of measuring in situ void formation [22,23], and (ii) the complexity of fluid dynamics modelling for the various flow paths and fibre architectures in industrial RTM processes.…”

Section: Introductionmentioning

confidence: 99%

High-resolution computed tomography in resin infused woven carbon fibre composites with voids

Sisodia

Garcea

George

et al. 2016

Composites Science and Technology

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Significance of paperRecent efforts in the composites industry towards less-expensive means to produce high-performance parts have often involved optimisation of liquid composite moulding processes such as resin transfer moulding (RTM). The most significant gap in part quality between RTM manufactured parts and traditional autoclave processes is the usually higher void content in the former, arising from the entrapment of bubbles during infusion, and the lower consolidation pressures used during such processes. Many laboratories around the world are working on understanding bubble entrapment and subsequent bubble mobility, so as to optimise RTM processes to reduce the concentration and size of voids. This paper contributes to that understanding with threedimensional examination using CT imaging of the morphology, size, clustering and location of the individual voids in composite parts made with RTM. Most important / novel contributionsThis paper presents visualisation of the voids in a composite part with significantly more statistical information regarding size distribution, orientation and location than has been previously shown in the literature. It also addresses a reinforcement architecture more typical to RTM, an un-balanced weave, than the unidirectional fabrics usually studied in previous work on void formation. Analysing a complex reinforcement along with the enhanced visualisation abilities of the CT-imaging technique allowed novel observations and conclusions regarding voids: 1) As the orientation angle between a reinforcement layer and the resin flow direction increases from parallel to perpendicular, larger voids and a greater number of voids were observed in that layer. This was linked to the resulting greater propensity for fatigue crack propagation between voids in layers transverse to the loading direction. A simple optimisation strategy is thus to infuse in a direction transverse to the expected primary load direction, thus creating the fewest voids in the transverse-to-load direction. 2) Voids accumulate around both the layer interfaces and yarns and are nearly completely absent from the layer thickness between those interfaces and away from yarns. 3) Void distribution follows the orientation of fibres in adjacent layers, suggesting that out-of-plane flow is a significant mechanism in void formation and mobility. 4) Observations 1-3 above all imply that current void formation and mobility models must be expanded from a microscale approach to the laminate scale, in order to focus on out-of-plane bubble movement and yarn bubble entrapment. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT AbstractTomographic imaging using both microfocus radiation and synchrotron radiation was performed to assess the void defects in resin transfer moulded woven carbon fibre composites. The focus of this study is on characterising the void homology (e.g. local void size and spatial distribution) in relation to weave orientation, infusion direction and potential effects on damage formation in tensile loadin...

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Reduction of void content of vacuum‐assisted resin transfer molded composites by infusion pressure control

Chen

Arakawa

2014

Polymer Composites

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Vacuum-assisted resin transfer molding is a promising technique for making large and complex composite structures. However, void formation remains a problem. Two primary contributors to void formation, nonuniform resin flow and continuous evaporation of resin under low pressure, were experimentally studied. Improved pressure control at the vent is proposed to reduce the void content of the manufactured composite material: at the start of the resin infusion, the pressure at the vent is set to the full vacuum of the equipment, while after the resin has saturated all of the reinforcements, the pressure at the vent is increased slightly. The full vacuum at the start of infusion avoids air entrapment, and the slightly higher pressure later in the process restrains the resin evaporation. A lower void content is obtained. POLYM. COMPOS., 36:1629-1637

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Modeling and simulation of voids and saturation in liquid composite molding processes

Cited by 170 publications

References 34 publications

Analytical prediction of void distribution and a minimum-void angle in anisotropic fabrics for radial injection resin transfer molding

Analytical prediction of void distribution and a minimum-void angle in anisotropic fabrics for radial injection resin transfer molding

High-resolution computed tomography in resin infused woven carbon fibre composites with voids

Reduction of void content of vacuum‐assisted resin transfer molded composites by infusion pressure control

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