Study On The Permeability Of Fiber Aggregation By Fractal Theory

In the process for manufacturing composites, such as the resin transfer molding, permeability is the important parameter for describing the resin flow, it can be used to token the hardness of resin flowing fiber aggregation. Permeability also is the important parameter for computer simulation, it help to design the fibrous reinforcements. The permeability decides the composite's quality and efficiency. So, it can be drive the RTM industrialization if we lucubrate the permeability of fibrous reinforcements and control the factor.In this paper, we study on the permeability with fractal theory. The fractal theory was putted forward in 1970s, it has unique advantage to describe and analysis the disorder object. The paper includes three aspects: first, we validated the structure of fiber aggregation accord with the fractal theory. Then we used the fractal theory to study on pore, Second, the fractal dimension of fiber aggregation was calculated by box-counting method with program, which based on the image analysis of section image. Third, the fractal analysis model was established by Hagen-Poiseulle equation and darcy's law, it is based on fractal capillary model. The validity of the proposed fractal permeability model is assessed by a comparison with experimental data.After analyzing, some deduction is confirmed. First, there are macro-pore and micro-pore in the fiber aggregation, the size and distribute of them are similar to the islands and lakes on the earth. So, the size and distribute of pore have the fractal character, we can use fractal theory to calculate. The fractal dimension of fiber aggregation was calculated by the program writing by VC++6.0, which based on box-counting method. Second, the permeability fractal model which educed by fractal capillary model and darcy's law, was compared to the experiment data, the result indicated that the fractal model can predict permeability primely. The fractal permeability model doesn't have experience constant, so it is better than the Kozeny-CarmanFinally, this dissertion illustrates the prospects of the developing direction of this topic.