The effect of tensile cyclic forces on the tensile properties of seams with different stitch density of knitted fabrics

Clothing seams are subjected to repetitive tensile forces due to body movements, which can impact both the appearance and mechanical properties of the seam. Knitted fabrics, known for their high elasticity, readily stretch and conform to the body. However, biomechanical forces resulting from human body movements influence not only the mechanical properties of the fabric but also the mechanical and aesthetic properties of the seam. This study aims to investigate the tensile behavior of different seams in weft knitted fabrics by utilizing three knitted fabrics to prepare samples with three distinct stitch densities. The tensile properties of the fabric and the sewn samples were measured, and the tensile behavior of the seams was examined after 25 and 50 cycles of tensile loading. The results indicate that in fabrics with low and unstable surface densities, the seam reduces elongation, whereas in fabrics with high elasticity, the opposite effect is observed. Furthermore, sewing with medium stitch density is more suitable for fabrics with low surface density and/or unstable fabrics, while high stitch density is more appropriate for knitted fabrics with high surface density. Additionally, with an increase in loading cycles, the strength of the samples gradually decreases, and the modulus of elasticity increases.