THE MECHANISM OF SEAM PUCKER IN STRUCTURALLY JAMMED WOVEN FABRICS

The present work has shown that the cause of seam pucker in structurally jammed fabrics is mainly due to the sewing tensions of the sewing threads and that the fabric instead of trying to take up a more jammed configuration, as believed so far, tries to resist jamming and in doing so, buckles out of the fabric plane. The proposed mechanism of seam pucker is based on quantitative and qualitative studies of fabric and thread properties in relation to sewing. The stitch can be regarded as an Euler column consisting of three springs representing a lockstitch seam; a compressed spring in the middle representing the fabric, and two stretched springs either side of it representing the needle and bobbin threads. If the bending and compressional loads are high compared to the bending and compressive stiffness of the fabric, buckling will occur. If the column is stiff by comparison with these loads, then the critical load for the column will not be exceeded and buckling will not occur.