Full field monitoring of the resin flow and laminate properties during the resin infusion process

Abstract

The resin infusion process (a.k.a. VARTM, SCRIMP) has developed as a low cost method for manufacturing large fibre reinforced plastic parts. This process still presents some challenges to industry with regards to reliability and repeatability, resulting in trial and error development being expensive and inefficient. This paper describes a fully instrumented resin infusion setup, providing preliminary experimental data acquired while varying influential parameters during the filling and post-filling stages. The laminate permeability is a strong function of the fibre volume fraction which can be determined from the laminate thickness. To assess the variation of the volume fraction and permeability, full field thickness variations have been monitored using a digital speckle stereophotogrammetry system developed for this purpose. In-mould resin pressures, flow front progression, and incoming resin flow rate were also measured. A selection of four experiments is presented here for discussion.

Numerical modelling of the flow in the resin infusion process on the REV scale: A feasibility study

“…We have tested the model with both constant and tensorial permeability for the preform (porous) medium and the results showed a reasonable agreement with the ones presented in similar studies [1,2,3]. Presence of different regions with different permeability and porosity has also been studied and the results showed that such a layup configuration may lead to an unsaturated region in the domain.…”

“…Its main intention is to provide a sustainable and consistent framework for the implementation and application of model concepts, constitutive relations, discretizations and solvers [5]. Figure 2(a), and they are similar to the results presented in the studies [1,2,3]. As seen in the figure, the resin fast fills up the distribution medium region, and then starts to impregnate the preform region.…”

“…Consequently, a part of the preform region is not fully saturated by the resin and that is one of the most common issues seen in the manufacturing process [1]. This issue can be solved by increasing the infusion pressure and/or increasing the process time in order to let the preform region get fully wetted by the resin [3]. It should be noted that curing of the resin (which is neglected in this study) also plays a role in the fluidity of the resin and hence the wetting of the preform region.…”

“…For this particular study, we assume that the third region has the characteristic properties of a Balsa wood (see Figure 3(a)) which is normally used as a core material in the manufacturing of wind turbine blades. The properties of the Balsa wood is chosen to be φ 3 Figure 3(b), due to the higher permeability of the Balsa region the flow reaches to the bottom of the domain faster than it moves in the preform region. Consequently, a part of the preform region is not fully saturated by the resin and that is one of the most common issues seen in the manufacturing process [1].…”

“…A distribution medium (resin feed line) is positioned over the peel ply to enhance the resin flow if the preform has low in-plane permeability. Once inlet and vent tubes are placed, the mould is covered with a vacuum bag sealed with sealant tape [3].…”