Sock fabrics: relevance of fiber type, yarn, fabric structure and moisture on cyclic compression

The objective of this study was to subject dry and damp sock fabrics to repeated compression cycles in order to determine the relative effects of fiber type (fine wool, mid-micron wool, acrylic), yarn type (high twist, low twist, single) and fabric structure (single jersey, half-terry, terry) on fabric compression and recovery from compression. Changes in fabric thickness were measured using a tensile tester and a number of parameters identified and analyzed: retained thickness, recovered thickness, compression to recovery ratio, energy absorption and energy absorption standardized for fabric thickness. The dominant factor was the number of compression cycles, with most change in the thickness retained and recovered evident within the first 10 cycles. The pattern of response of dry and damp fabrics was quite different with, the dry fabrics having a better compression to recovery ratio. Energy absorption was affected strongly by fabric structure, however this was closely related to initial fabric thickness. When fabrics were made damp, fabrics composed of acrylic fibers had a better compression to recovery ratio than fabrics composed of wool.