UNIT-CELL GEOMETRY IN PLAIN-WEAVE FABRICS DURING SHEAR DEFORMATIONS

The evolution of microstructure in dry plain-weave fabric during large shear deformation is described. The entire geometry of the unit cell is defined by four sinusoidal curves in terms of the yam width, yarn s pacing and fabric thickness. The change in micro-structural throughout shear deformation prior to wrinkling is predicted by using only measu red parameters from the undeformed fabric. Comparisons between the pre dicted and experimental values are included. The microstructure is sho wn to evolve considerably prior to wrinkling. Expressions relating fib er volume fraction to the level of shear deformation are also presente d. The possibility that unit-cell volume fractions may vary by a facto r of two in parts with complex curvature is shown to exist. Implicatio ns for manufacturing issues such as preform permeability and thermal c onduction during forming and for mechanical property prediction of tex tile composites are discussed. (C) 1997 Elsevier Science Limited.