The Effect of Bonded Seams upon Spatial Behaviour of Knitted Materials Systems

Abstract

Spatial behaviour of knitted materials with bonded seams under biaxial tensile loading is analysed in this work. The objects of the research were plain jersey and rib 1×1 polyester knitted materials with elastane (93 % PES, 7 % EL). Two thermoplastic polyurethane (PU) films different in thickness (75 mm and 150 mm) were used. For each sample of knitted material and thermoplastic film five types of bonded seams (10 mm in length) were prepared by changing the orientation of knitted material strips, i.e. parallel/parallel, parallel/bias, parallel/perpendicular, bias/bias and bias/perpendicular. The effect of thermoplastic films type and the effect of knitted materials orientation in seam was analysed on the basis of biaxial tensile characteristics – critical punching force P (N) and corresponding punching height H (mm). The changes of tested specimens strength and deformation properties were compared before and after their cyclical fatigue punching (50 cycles; punching force P = 50 N). Obtained results have shown that  changes before and after cyclical fatigue punching are mostly determined by the type of thermoplastic film, but not effected by the orientation of knitted materials pieces in bonded seam.