Assessment of seam tensile behaviour in weft knitted fabric after cyclic loadingthe influence of fabric loop length

Abstract

This study investigates the tensile behaviour of seams in knitted fabrics under cyclic tensile loading to simulate everyday wear conditions. Single jersey polyester fabrics with varying loop lengths were sewn using two common stitch types (504 and 514) and subjected to cyclic loading up to 200 cycles. The effects of stitch type, fabric loop length, and cyclic loading on the tensile properties of the seams were evaluated. The results revealed that the breaking stress and strain of the sewn fabric were lower than those of the unsewn fabric, owing to the loss of fabric integrity. In contrast, cyclic loading significantly reduced the seam breaking strain and increased the tensile modulus, indicating reduced seam extensibility. Moreover, fabrics with longer loop lengths exhibited reduced extensibility and poorer fatigue recovery. These findings indicate that fabrics with shorter loop lengths exhibited higher breaking strain and lower tensile modulus. It was also suggested that stitch type 504, especially in small stress, is more suitable, particularly for fabrics with greater extensibility.