Design and construction of a bending tester for textiles

Abstract

Bending rigidity is an important physical parameter measured in Textiles. The drape and handle qualities of a textile are governed mainly by its bending and torsional characteristics. These can be changed only by using suitable softeners or various finishing agents. Many attempts have been made to develop instruments to measure the bending rigidity of textiles using various principles. The aim of some research activities is to relate the bending properties of constituent fibres and yarns to fabric properties. According to one school of thought properties such as bending, torsion, strength, friction and compression arc measured to predict the overall drape and handle qualities of fabrics. Much work is being done in the objective evaluation of properties of textile structures which should replace subjective evaluation methods Up to now there is no standard instrument to measure each of these parameters including the bending rigidity All though there are several commonly used methods for measuring the bending rigidity of yarns and fabrics. not all satisfy the desirable condition that a pure bending couple should be imparted to the test specimen. Such a method has an advantage over other methods in that the specimen experiences only a bending moment. The apparatus described in this work has been designed to impart an almost pure bending to the specimen under consideration over its entire length. Also it was attempted to ensure that the equipment is made versatile in as many aspects as possible. A cyclic bending tester was designed and constructed to achieve the above mentioned aims. Unlike the earlier versions this tester was controlled by computer. The principle employed was that of the cloth bending tester designed by Livesey and Owen |l|. later improved and extended by Abbott|2|. Grosbcrg|3|. Chapman|4| and Grcy|5|. This tester was made with more precisely controlled movement and with greater sensitivity. adjustable to measure yarns and fibres and with overall control using an IBM Personal Computer