Analysis of resin injection molding in molds with preplaced fiber mats. II: Numerical simulation and experiments of mold filling

Abstract

This work presents the results of numerical simulation and experimental visualization of the mold filling process in resin injection molding with preplaced fiber mats. The mold filling experiments were conducted with various mat stacks consisting of continuous random glass fiber mats and bidirectional stitched glass fiber mats. The use of two different mat types in the mat stack created porosity and permeability variations. The effect of these permeability variations was studied by taking flow pressure measurements and observing the progress of the flow front of a non-reactive fluid filling a clear acrylic mold that contained the reinforcement mat stack. Numerical simulation corresponding to each experiment was also carried out. The numerical results were compared to the experimental measurements.

Control Volume Finite Element Methods for Flow in Porous Media: Resin Transfer Molding

“…Other techniques based also on the observation of the moving resin front are common in the literature [43,[51][52][53][54][55][56][57][58][59]. However, transparent mold walls may not have enough rigidity to avoid deflection, which has been shown to perturbate the measured permeability values [45,48,49,54]. In this context, the University of Plymouth radial flow permeability appartus was enhanced by the use of a laminate of two 25 mm toughened float glass sheets [60] as the upper mould tool to achieve a similar stiffness to the aluminium mould base [61].…”

“…Trevino et al [48] and Young et al [49] determined unidirectional permeability using two pressure transducers at each of the inlet and the exit in conjunction with an equation based on Darcy's law applied to their flow geometry. Calhoun et al [50] presented a technique based on placing several pressure transducers at various locations inside the mold.…”

“…This type of approach was first presented by Wang and others and was adopted in the case of thin shell injection molding [5]. Fracchia was the first to apply the CVFEM to simulate the RTM process [6] and other researchers also followed this approach [7][8][9][10][11][12][13][14][15][16]. The application of these methods generate several commercial software: RTM-FLOT ( no longer supported ), PAM-RTM, MyRTM and LIMS.…”

Effect of Preform Thickness and Volume Fraction on Injection Pressure and Mechanical Properties of Resin Transfer Molded Composites

“…Other techniques based also on the observation of the moving resin front are common in the literature [10,11,17,[25][26][27][28][29][30][31]. However, transparent mold walls may not have enough strength to avoid deflection, which has been shown to perturbate the measured permeability values [10,11,22,23]. In addition, the use of a camera or multiple transducers placed on the mold walls may not be practical for many RTM applications.…”

“…Trevino et al [22] and Young et al [23] determined unidirectional permeability using two pressure transducers at the inlet and the exit in conjunction with an equation based on Darcy's law applied to their flow geometry. Calhoun et al [24] presented a technique based on placing several pressure transducers at various locations inside the mold.…”