Experimental research of saturated permeability with different fiber stacking states

By regulating the pressure to control the volume fraction of fibers V_f, the saturated permeability along the thickness of the fiber bed was measured by the unidirectional saturated flow method. The influence of pressure on V_f was investigated. Several factors which affect the permeability were studied, including V_f, the number of layers of the fiber bed, the ply stacking sequence and the kinds of fibers. The results indicate that the degree of increase of V_f with pressure decreases when V_f exceeds a critical value. The number of layers does not affect the permeability for the unidirectional and bidirectional ply stacking while for the plain weave the permeability decreases with the number of layers. In addition, the kinds of fibers influence the permeability remarkably.