Experimental and Numerical Study on the Permeation Behavior of Foam-core Sandwich Panels in LCM

The foam-core sandwich panel is a widely used high-performance structure in a variety of applications, which has been successfully manufactured by liquid composite molding (LCM). During the filling process of LCM, flow-induced defects inevitably occur, like dry spots and voids, particularly in complex structures. In industry, it is pervasive to introduce distributed grooves or holes in foam cores to optimize the resin flow channels, therefore reducing the likelihood of defects. This study aims to experimentally and numerically investigate the effect of grooves and holes on the permeation behavior of the foam-core sandwich panel. The filling process simulation was first performed to characterize the permeation behavior of the foam-core sandwich panel. The simulation results fitted the experimental results very well. This verified simulation method was further used to evaluate the influence of holing or grooving treatment of foam cores on the permeation behavior, which were characterized by flow pressure, flow front, and filling time. Both experimental and numerical results indicated that holing and grooving treatments could improve the filling pattern and the mold filling time. Notably, the effect of grooving treatment on foam cores was more effective in enhancing the impregnation of reinforces.