PERMEABILITY CHARACTERISTICS OF MULTILAYER FIBER REINFORCEMENTS .1. EXPERIMENTAL-OBSERVATIONS

The fluid permeability characteristics of homogeneous and heterogeneous multilayer fabric assemblies were determined by a radial in-plane flow technique. The permeabilities and flow anisotropies of multilayer assemblies generally differ from those of the constituent layers. In homogeneous assemblies, the creation of interlaminar pores can increase the effective in-plane permeability. In heterogeneous assemblies, the effective in-plane permeabilities and anisotropies are governed by the high permeability layers or directions. A transverse flow mechanism contributes to filling the low permeability layers and keeping the fluid front macroscopically uniform.