The Relationship Between the Structural Geometry of a Textile Fabric and Its Physical Properties

This paper is a study of the geometry of fabric interstices as related to air flow through cloth structures. It assumes that textile yarns act as flexible, inextensible, circular cylinders. Modes of thread interlacing are classified, and minimum horizontal pore areas for each type of intermesh are calculated. Minimum pore areas are then related to the air permeabilities of both open- and close-weave fabrics. Considerable attention is devoted to the elements of fabric structure which complicate geometric calculations of pore-sectional areas. These include crimp balance and yarn flattening and ballooning. Further attention is given to the relative importance of interfiber spacings and to the interaction between yarn and fabric structures. Finally, this study emphasizes the significance of the primary and secondary structural features of woven fabrics in the design of materials which must satisfy air-permeability requirements.