No abstract

A method to study the forced in‐plane flow of an epoxy resin into fibrous networks is presented. A radial in‐plane flow apparatus has been developed which allows strict control of all important experimental variables as well as visual observation of the experiment. From the position and shape of the advancing resin front as a function of time, effective directional permeabilities are obtained and used to compare structurally different fibrous networks. Test results for an initial series of woven and nonwoven fabrics reinforce the method of data analysis and demonstrate the effects of pore structure, weave type, weave balance, fabric layering, fiber orientation, and compressibility.

A technique that quantifies the in-plane flow properties of fibrous networks is pre sented. A radial flow geometry allows the simultaneous study of more than one in- plane flow direction. The shape and position of a radially advancing fluid front define directional permeabilities in the plane, which can be used to compare structurally different fibrous networks. Confirmatory studies reinforce the method of data analysis and show that the directional permeabilities are independent of driving pressure, fluid viscosity, and fiber surface wettability properties. The methodology was applied to the study of multilayer assemblies. The in-plane flow of fluids in heterogeneous multilayer constructions is governed by the high permeability layer. A transverse flow mechanism is proposed as being responsible for filling the low permeability layers and, therefore, the transverse permeability is coupled into this flow process.