Experimental matrix permeation studies of unidirectional composite materials

Experimental testing was done for rheological permeation models of unidirectional composite materials. Large scale test bundles were made to simulate unidirectional fiber tows. Both transverse and longitudinal permeability cases were investigated as well as constant pressure gradients and varying pressure gradients for both Newtonian and non-Newtonian fluids. Experimental results were compared with a numerical permeation model. Experimental results compared favorably with numerical models for transverse Newtonian flow. Because transverse flow was present in the longitudinal flow tests, longitudinal Newtonian flow results were not as accurate. A parameter comprised of the product of the coefficient of drag and the Reynolds number was used to present experimental non-Newtonian results. For Newtonian flow, the CdRe number was constant as pressure gradient increased, and tended to increase as the solid volume fraction increased. Experimental Newtonian CdRe values compared favorably with numerical models. For non-Newtonian flow, CdRe values increased and leveled off asymptotically as pressure gradient increased. CdRe values increased with solid volume fraction and decreased as power-law indices decreased from one (unity). No numerical data were available for comparison with non-Newtonian experimental flow results.