Bestimmung der Permeabilität von flächigen Faserhalbzeugen

Translated title of the contribution: Permeability measurement of two dimensional textile preforms

Harald Grössing

Research output: ThesisMaster's Thesis


Nowadays fiber based polymer composite materials are used in automotive, aerospace and wind power industry. To achieve the highest levels of quality and properties, the parameters like permeability, of the Liquid Composite Moulding (LCM) process have to be evaluated. A very important parameter for LCM is the textile impregnation time, which is directly related with the permeability of fibre textiles. Measurement of permeability supplies useful information about the infiltration process. The main aim of this work is to compare different permeameter systems regarding the resulting permeability values. The experimental work will focus on the reproducibility of Non-Crimp Fabrics (NCF). Other attempts should show the influence of numbers of layers, the injection pressure and the handling on the permeability. For practical work an optical and an electric capacity measurement system are available to determine the permeability of NCF. This thesis also concerns the implementation of a calculation software to determine anisotropic permeability values. The first result was a MatLAB- code which is able to calculate anisotropic permeability values. Two existing permeameter systems have been investigated. It could be shown, that the optical permeameter doesn´t work exact, because the glass plate is bending up and the consequence is a local change of the cavity hight. In further investigations it could be shown, that the injection pressure and the numbers of layers have no significant influence on the permeability. With regard to the reproducibility it can be said, that each individual measurement has a very high standard deviation. The highest standard deviation, more than 50%, were detected at the two bar and eight bar attempts. So the reasons of these deviations are material errors like orientation differences between the 0° and 90° layers and missing rovings in the 0° layer. The handling, treatment and the transportation are taking more significant influence on the permeability. A very rough treatment of the preform ensures that the permeability of the major axis is 50% and the permeability of the minor axis is 120% higher than the permeability’s from an untreateted preform. Also the transportation left it´s traces behind. The permeability of both axes is more than 80% higher than the permeability from the reference.
Translated title of the contributionPermeability measurement of two dimensional textile preforms
Original languageGerman
  • Schledjewski, Ralf, Supervisor (internal)
  • Wolfahrt, Markus, Supervisor (external)
Award date30 Mar 2012
Publication statusPublished - 2012

Bibliographical note

embargoed until 06-03-2017


  • permeability
  • liquid composite moulding
  • fiber based preforms

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