A fractal in-plane permeability model for fabrics

In this paper, a fractal in-plane permeability model for various fabrics is developed. The model is based on the fractal characteristics of pores in fiber preforms. Four different glass fabrics are considered in the modeling: plain woven, 4-harness, bidirectional stitched, and continuous strand random mats. The fractal in-plane permeability model can be expressed as a function of the pore area fractal dimension and architectural parameters of the fiber preform. This model also relates the permeability to porosity changes of fiber preforms under compression, which usually occurs in the molding processes. To verify the applicability of the model, the results from the present fractal model are compared with those from the one-dimensional analysis model and with a set of permeability measurements. Good agreement is found between the two models and the permeability measurements in the general porosity ranges of interest.