Modeling the impact of capillary pressure and air entrapment on fiber tow saturation during resin infusion in LCM

Stokes–Brinkman formulation for prediction of void formation in dual-scale fibrous reinforcements: a BEM/DR-BEM simulation

“…For the second weft, the void is smaller as C cap increases. The total void size, which is the sum of the size of both bubbles, also decreases with C cap , which is in agreement with the results of [30]. On the other hand, the void aspect ratio in both wefts increases with C cap .…”

“…Although the size of the first bubble is not a monotonic function of C cap for both values of β, with the smaller voids corresponding to C cap = 5 × 10 −1 and the larger ones, to C cap = 1 × 10 −1 , the size of the second bubble is a decreasing monotonic function of C cap , and the resulting total void size, which is the sum of the size of both bubbles, also decreases with C cap . This last behavior is in agreement with results previously reported in the literature [30], where unidirectional macroscopic simulations were carried out using the software LIMS and it was found that the saturated length corresponding to the arrival of the fluid front to the end of a cavity is larger as C cap increases, which, from a mesoscopic viewpoint, can be interpreted as the reduction of the total void size with the increment of C cap for a given position along the cavity. In general, the void shapes obtained in this work are physically consistent with some experimental works.…”

“…As it can be noticed from (21) to (30), the maximum capillary pressure in the present case is always achieved at the symmetric boundary of the warp, and it is given by: …”

“…As a constant inlet pressure condition is considered in all simulations, the comparison between the pressure and capillary forces is described by the capillary ratio, C cap = P cap,max /P in , as defined in [30], where P cap,max and P in stand for the maximum capillary pressure and inlet pressure, respectively. For Series 1, 2 and 4, three different capillary ratios are contemplated: C cap = 1×10 −2 , C cap = 1×10 −1 and C cap = 5 × 10 −1 , whereas for Serie 3 only the lower value of C cap is taking into account, i.e, C cap = 1 × 10 −2 .…”

Dynamic capillary impact on longitudinal micro-flow in vacuum assisted impregnation and the unsaturated permeability of inner fiber tows

“…Amico and Lekakou [15] reported the influence of capillary pressure on estimation of permeability of a plain-weave glass fiber fabric. And recently, Advani and coworkers [16] modeled the capillary action on fiber tow saturation during resin infusion by introducing theoreticallyestimated capillary pressure in flow simulation. However, as for the dynamic of penetration flow, capillary pressures are always deemed to act as promotive force, which is found not to be true the cases of vacuum driving impregnation in unidirectional fiber bundles in this study.…”