Numerical evaluation of the transverse permeability determination experiment

Abstract

Polymeric composites produced by liquid molding are becoming more and more common in nowadays applications. Quality control of the produced parts relies on precise evaluation of the manufacture parameters and physical properties. Permeability is one of these important properties and the subject of present work where mold design for transverse permeability (out-of-plane) determination is investigated. The most used mold design is based on a resin rectilinear (one dimensional) flow which is forced through the fibers. To assemble it inside the mold cavity, two perforated plates are used. The geometry of these plates, as well as the distance between them, directly influences the calculated permeability, however quantification of this influence is not well documented in literature. Furthermore, the anisotropy (K _xx /K_zz ratio) of the material is evaluated as a factor that intensifies the influence of flow distortions that vary with the plates used. A numerical study has been performed to quantitatively evaluate how much these parameters may affect the calculated permeability. Results have shown that errors up to 40% may occur if a wrong setup was used in materials with low permeability ratios. Better accuracy is obtained for materials with higher ratios regardless of the used perforated plate.