Analysis and minimization of void formation during resin transfer molding process

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

“…It should be noted that the porosity of the fiber bundles is assumed to be the same in both directions [23,24]. In addition, the capillary pressure in Equation (1) is determined using the Young-Laplace equation represented by Equation (8) [29]: where γ is the surface tension of the resin, C is the geometric correction factor, θ c is the contact angle between the resin and the fibers, and r c is the capillary radius of the fiber bundles specified by Equation (9). The geometric correction factor C is obtained by fitting the data from the measurement results in the voidfraction experiments with the results acquired using the estimated model.…”

“…The voids formed during the impregnation may be classified as macro-scale voids, mesoscale voids or micro-scale voids depending on their size. A macro-scale void is also called a dry spot and is formed in the domain where the fabric is not impregnated by the resin because of inappropriate molding conditions [9][10][11]. A meso-scale void is caused by inter-bundle air trapping resulting from the differences between the high value of the intra-bundle resin velocity and the low value of the inter-bundle resin velocity [12][13][14].…”

Efficient stochastic simulation approach for RTM process with random fibrous permeability

“…Although studies have been performed on the probabilistic characterization of the random transport properties of fibrous media [2][3][4], the random effects are usually neglected in the available optimization or on-line control schemes [5][6][7] which employ common simulation softwares for mold filling. Available stochastic studies in the RTM context [8][9][10][11][12] mostly depend on the Monte Carlo simulation (MCS), which is computationally expensive for a fast uncertainty analysis or to be combined with other algorithms for optimization or sensitivity analysis.…”

Multiscale modeling of combined deterministic and stochastic fabric non-uniformity for realistic resin injection simulation

“…However, this refers only to meso/macroscale dry spots, not to microscale voids which are caused by differences in flow velocity between interyarn gaps and yarns and capillary pressure as discussed, e.g. by Lee et al 35 These effects cannot be assessed here since the mesoscale fabric structure was homogenized for flow modeling.…”