One step to comparable off-plane permeability results - an improved measuring method for transverse permeability and compaction behavior of textile fiber materials

For the conventional transversal permeability test equipment, the preform cavity is limited by distribution structures for the test fluid (usually metal plates with an equidistant distribution of holes). These structures are used to provide a uniform fluid flow throughout the preform. The distance in between the structures defines the fibre volume content (FVC) of the preform under the assumption that the preform is homogenously compacted. In this study the influence of the distribution structures on the homogeneity of the fibre volume content is investigated. For this purpose, an experimental device was developed that allows the preform to be cured at identical conditions compared to the permeability test equipment. FVC measurements were made to examine the assumption. First test series confirm that the distribution structures indeed have an important impact on the results. This effect can be an explanation for the inconsistency of test results for off-plane permeability when different equipment (especially different distribution structures) is used.