Impregnation Molding of Particle‐Filled Preceramic Polymers: Process Modeling

Abstract

A process model is presented for the analysis and simulation of impregnation molding of particle-filled, continuousfiber ceramic composites. A multidimensional, transient particle filtration formulation is coupled with isothermal, anisotropic Darcy flow to predict filler-concentration profiles during molding. The particle filtration is insensitive to the injection flow rate; however, in irregularly shaped molds, the geometry of the mold greatly influences the local velocities, which results in local variations in the rate of filtration. Although the preform volume fraction and inlet particle concentration influence the particle accumulation quantitatively, the filtration coefficient and the permeability have a dominant role in setting the filtration trend.

Coupling filtration and flow during liquid composite molding: Experimental investigation and simulation

“…Concerning the filtration of particle-filled resin through a fibrous preform during composite processes, some models and investigations have also been published. Filtration models were based on macroscopic approaches coupling kinetics of retention to conservation of mass [10,7,12]. Chohra et al used a geometric and probabilistic model to represent retention of particles in the thickness direction during infusion process [5].…”

“…The output of that solver is the suspension velocity U. Filtration sub-model: A finite element method is used to solve for Eqs. (3), (4), (6), and (7). A commercial code (COMSOL Multiphysics 3.3, COMSOL AB) is used.…”

Modelling the flow of particle-filled resin through a fibrous preform in liquid composite molding technologies

“…In the most severe conditions when use of high fiber content fabrics is necessary, mold filling may be difficult or impossible. However, few researches related to the flow of particle-filled resin through a fibrous preform has been published [7,10].…”

“…Hence, both experimental and theoretical studies have been published on these particular matters. In the case of composites manufacturing, filler content, flow velocity, fluid viscosity do not belong to the same range, so the filtration theory equations need to be derived [10]. A macroscopic model of filtration during the flow of a particle-filled resin through a fibrous preform has already been proposed by Erdal et al [10].…”

“…In the case of composites manufacturing, filler content, flow velocity, fluid viscosity do not belong to the same range, so the filtration theory equations need to be derived [10]. A macroscopic model of filtration during the flow of a particle-filled resin through a fibrous preform has already been proposed by Erdal et al [10]. However, they were not able to validate a reliable way of characterizing the filtration during impregnation [11].…”