Anisotropic in‐plane permeability of fabric media

Abstract

An elegant procedure is proposed for obtaining components of the orthotropic or anisotropic in‐plane permeability tensor from experimental data on flow front position and time. A radial flow geometry allows the shape of the advancing flow front to be dictated by the in‐plane permeability of the fabric media. The directional permeabilities in the fabric plane are directly calculated from fluid and fabric properties together with data from the mold filling experiment (resin injection pressure and flow front position with time). The simplicity of the apparatus and proposed analytical procedure permit easy testing and comparison of different types of fibrous media.

An evaluation of the reproducibility of capacitive sensor based in-plane permeability measurements: A benchmarking study

“…They are needed to determine the corresponding highest (K1) and lowest (K2) in-plane permeability values with a mathematical algorithm after having executed the permeability measurement. Adams and coworkers [32][33][34][35] and Chang and Hwang [36] are describing two different and independent algorithms for in-plane permeability calculation. Anisotropy $ is a coefficient which describes the relationship between the major and minor axis permeability.…”

“…The determination of the preform permeability values and the orientation angle of the occurring ellipse to a reference axis are still challenging problems from experimental and theoretical points of view. The knowledge about the timely flow front advancement is the most important fact for an accurate permeability calculation [32][33][34][35][36][37]. In order to calculate the permeability values of the investigated preform, the major and minor axis lengths of the occurring ellipse are needed.…”

“…Anisotropy $ is a coefficient which describes the relationship between the major and minor axis permeability. The anisotropy coefficient is defined as the quotient of K2 and K1 [32,36,37]. For the in-plane permeability measurements different permeability test rigs are described in the literature.…”

Experimental Investigation of the Effect of Short Flax Fibers on the Permeability Behavior of a New Unidirectional Flax/Paper Composite

“…Once K e is obtained, the permeability in the x and y directions (K x and K y ) can be calculated. The calculation details are given in Albert et al [26].…”

“…Fiber flexibility determines fiber deformation during compression, which in turn affects inter fiber porosity [27,28]. Second, flax fibers have a thicker cell wall [29] than Kraft fibers [26]. Thinner cell walls will collapse (flatten) more easily and create a network that conforms better under compression forces [30,31].…”