The excellent processing properties of knitted preforms for composite applications, as formability and permeability, are not sufficient to compensate the poor mechanical characteristics of the resulting material. Initial preform deformation is a way to improve these properties, but it modifies the permeability and changes the optimal infiltration conditions. This article presents an experimental setup and discusses the reliability of the permeability measurements. Experimental results show that the course-wise permeability is significantly modified by the deformation of the fabric, whereas the wale-wise permeability is quite insensitive to the deformation. In an equivalent isotropic system, the deformation essentially influences the anisotropy ratio.
展开▼
