Compressed loop method for the bending behaviour of coated and laminated fabrics analysis

Fabric stiffness is one of the most important parameters in estimating the wear and comfort properties of multilayered textile materials. The characteristics of bending stiffness may be determined using different test methods. The aim of this work was to apply the compress hanging loop method for the evaluation of stiffness of coated and laminated fabrics. In order to achieve this purpose an extension machine appropriately equipped with a special device for specimen fixing has been used in this work. The initial and ultimate geometrical characteristics of the loop, and also the forces that were necessary to compress the loops to a certain degree were determined in this work. The investigation reveals that the force, which is necessary to compress the loop to a stated degree, is different not only for specimens cut in various directions but also for those specimens that are of different size. Therefore, the deformation properties are dependent on the material structure and testing conditions. The results indicate that coated and laminated fabrics with larger surface weight were more resistant to compression force. Also for these fabrics the larger difference of compressing force values was determined when the polymer film had been in different loop sides. It should be noted that analysis of geometrical compressed loop characteristics showed that for all tested specimens the upper and lower ratios of formed semicircles were not equal. The investigation reveals that the hanging compressed loop method allows extending the range of tested materials, which include rigid and less rigid fabrics.