Study of composite compressive properties due to biaxial deformation of the weft-knitted glass fabrics

The effect of biaxially deforming a weft-knit Milano rib fabric on the overall composite compressive properties has been studied for a glass/vinyl-ester knitted composite. A range of combinations of wale-course stretch ratios was considered. It was found that the compression properties of these structures, on the whole, appeared to be closer to isotropic and relatively insensitive to fabric deformation. This observation is believed to be due to the dominance of the matrix properties. Despite not detecting any gross changes in the knit structure, it is believed that some redistribution and reorientation of the fibres did occur during fabric deformation, which in turn altered the relative contents and/or directionality of the fibres in the composites. A feature of the compressive failure was kinking of the highly bent yarns, particularly in resin rich regions having reduced lateral support for yarns