Analysis of Compressibility Behavior of Hand-Knitted Carpet Pile

The existing standards for measuring carpet properties consider carpet behavior after loading while its dynamic and instantaneous behavior is neglected. To investigate the dynamic behavior of under loading carpets, an INSTRON machine equipped with a developed system was used. The reliability of the system was verified by testing different materials. Different samples of hand-knitted carpet with 30, 40, 50, 60 and 70 Raj (rows/6.5cm), with specific structural and physical characteristic and raw material, were tested to obtain the curves of their pressure resistance versus time. The relation between features derived from the load/time curves and carpet structural and physical characteristics and raw materials were defined. Measuring the Pearson coefficient correlation, the linear correlations were studied and analyzed. The results indicate that with increase in knot density (Raj), the rate of decreasing thickness during loading, the resilience of carpet pile after loading, the total work exerted to carpet for reaching to jamming phase and the work returned by carpet during recovery phase decrease; while with increase in carpet thickness, the resilience and the total work increase. In addition, the load/time curves of different materials and hand-knitted carpets were compared. The similarities and differences between their behaviors were derived and the desirable compressibility behavior of a carpet is accordingly suggested.