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Investigation of the influence of textile compression on the out‐of‐plane permeability of a bidirectional glass fiber fabric
Author(s) -
Endruweit Andreas,
Luthy Thierry,
Ermanni Paolo
Publication year - 2002
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.10455
Subject(s) - materials science , composite material , permeability (electromagnetism) , porosity , compressibility , permeameter , composite number , relative permeability , mold , mechanics , hydraulic conductivity , geology , genetics , physics , membrane , soil water , soil science , biology
In Liquid Composite Molding (LCM) processes, the out‐of‐plane component of the textile permeability varies with the applied injection pressure because of compression of the textile. A correlation of the compressibility measured on a testing machine and the behavior in a flow channel gives information about the compression for dry and wet preforms in the LCM mold during resin injection. The permeability for injection pressure values between 0.1 MPa and 0.5 MPa has been measured for various initial porosity values with five pressure cycles each. A steady state permeability value has been defined, averaging the permeability values in the pressure range of 0.1 MPa to 0.5 MPa excluding the hysteresis effect of the initial pressure cycle. A relation between this steady permeability and the given initial porosity and injection pressure has been found, replacing the Kozeny‐Carman formula for the description of the permeability of compressed textiles. Based on the same idea, a formula for description of the variations in permeability for increasing pressure in the first pressure cycle has been found. In this empirical formula, the term describing the influence of the injection pressure varies from the one found for the steady state permeability.