Evaluation of the knitted fabrics stiffness through dynamic testing

Abstract

The paper aims at introducing a qualitative method for the evaluation of warp knitted spacer fabrics stiffness, through the measurement of their natural frequencies, considering the direct relationship between natural frequencies of the textile fabrics and their stiffness. Additionally, the goal of this work was to comparatively evaluate the results obtained by two testing methods that utilise different measurement principles. The experimental design included the free vibration method, employed to measure the natural frequencies of the spacer mesh structures produced on K. Mayer RD 6 N double needle bar machine, manufactured in two variants of thickness and widths.The natural materials frequencies have been recorded coursewise, walewise and perpendicular on the fabric surface. The testing results confirmed the influence of the fabric thickness, the samples having lower thickness being characterized by the highest level of natural frequencies and stiffness. In parallel, the analysis of the knitted spacer fabrics’ flexibility was performed, allowing a comparison of fabrics stiffness and validating the dynamic test results.