Impregnation of Composite Materials: a Numerical Study

Abstract

Oxide ceramic matrix composites are currently being developed for aerospace applications such as the exhaust, where the parts are subject to moderately high temperatures (≈ 700 • C) and oxidation. These composite materials are normally formed by, among other steps, impregnating a ceramic fabric with a slurry of ceramic particles. This impregnation process can be complex, with voids possibly forming in the fabric depending on the process parameters and material properties. Unwanted voids or macroporosity within the fabric can decrease the mechanical properties of the parts. In order to design an efficient manufacturing process able to impregnate the fabric well, numerical simulations may be used to design the process as well as the slurry. In this context, a tool is created for modeling different processes. Thétis, which solves the Navier-Stokes-Darcy-Brinkman equation using finite volumes, is expanded to take into account capillary pressures on the mesoscale. This formulation allows for more representativity than for Darcy's law (homogeneous preform) simulations while avoiding the prohibitive simulation times of a full discretization for the composing fibers at the representative elementary volume scale. The resulting tool is first used to investigate the effect of varying the slurry parameters on impregnation evolution. Two different processes, open bath impregnation and wet lay-up, are then studied with emphasis on varying their input parameters (e.g. inlet velocity).

Nanocellulose-Based Nanocomposites for Sustainable Applications: A Review

“…Baché et al [184] mentioned the initial step of the manufacturing process is a complicated issue with numerous conceivable final saturation profiles due to the various processes and materials that can be applied. Process parameters (e.g., pulling velocity) and materials characteristics (e.g., slurry viscosity and fabric geometry), for example, have a significant impact on impregnation, with each set of slurry and fabric qualities necessitating a certain pressure and impregnation duration.…”

A polymer infiltration and pyrolysis (PIP) process model for ceramic matrix composites (CMCs)

“…Impregnation of alumina matrix in eight‐harness satin Nextel 610 fabric has been studied numerically in Ref. [24]. Modeling approaches used in the above work generally involved modeling the flow of a high viscosity resin through porous media and modeling the chemical reactions and volumetric changes during processing.…”