Mechanical Characteristics of Coated Fabrics

Abstract

When fabrics are coated, their deformation behaviour ehanges eonsiderably. The tensile, shear, and bending properties of four typical coated fabrics have been measured using the FAST system and an Inslron tensile machine. The fabrics were measured before coating, after eoating and after subsequent stretching or shearing treatment. Empirical polynomial functions were fitted lo the experimental load-extension curves to allow the calculation of strain energies for comparison purposes. Mechanieal treatment in the form of stretching or shearing partly restored the original fabrie properties and so might be beneficial In apparel applications. INTRODUCTIONEarly research [11 on the deformation behaviour of coated fabrics had as its aim the development of suitable measurement techniques, much of the interest concentrating on hovercraft skirt materials and their strength. Recently, the use of coated fabrics in garments has increased, particularly for clothes with a special performance need, such as to be waterproof, flame-resistant, etc. Improving the handle and drape of these materials has grown in importance with their increasing use.It is well known that fabrics become stiff and papery after coating. Their handle and drape properties deteriorate, mainly because the material of the coating fills the spaces between the yams and cements the warp and weft threads together. The mechanical behaviour of the yarns is changed and relative rotation of the yarns at interlacings is inhibited. The coating material itself has a specific response to applied load. These effects make a theoretical description of the deformation mechanism (structural mechanics) of coated fabrics difficult to achieve.In the present work a physical approach is taken in attempting to change the properties of coated fabrics, to obtain properties closer to the original properties of the uncoated fabrics. The intention is to reduce the internal constraints on the yarns (improved by the coating) through the application of simple mechanical treatments.The present work is part of a research project concentrating on investigating the feasibility of the FAST instruments to measure a wide range of apparel fabrics currently used by clothing manufacturers in the UK. Here an initial study is reported only, because a limited number of coated fabrics were involved in the experiment. The aim of the work is to examine the effect of coating materials on original mechanical properties of fabrics, and to demonstrate the utility of simple mechanical treatments in improving the mechanical properties associated with handle and drape in coated fabrics used for apparel applications.

Direct stress–strain representation for coated woven fabrics

“…Fabric stress-strain curves are described as ÔdiscontinuousÕ in that they have distinct non-linearities (Fig. 1) and hence are difficult to model with a polynomial function [14,15]. A NURBS representation is required if these non-linearities include an instantaneous change in curvature.…”

“….p 4 ) were used to fit this polynomial, but the resultant function did not adequately represent the test data. Chen et al [15] used a simpler second order polynomial to fit the stress-strain data. This enabled the tensile modulus at a given stress level to be derived easily by differentiation.…”

Elektronik Tekstillere Yönelik Akıllı Kumaş Sensörleri

“…Etanol ve ozon tespit etme, elektrokimyasal kaplanmış PPy filament sensörleri kullanılarak elde edilmektedir [92]. PANi esaslı optik lif HCl ve NH 4 OH'e maruz kaldığında ışık emilimi değişmektedir.…”

Stochastic modelling of tear behaviour of coated fabrics

“…However, for a description of the tearing behaviour with acceptable accuracy, no satisfactory model is presently available, while current research work aimed at developing such models has been mainly experimental and semi-empirical [16][17][18][19].…”

“…As a critical indicator of the serviceability of a fabric, tearing strength is rigorously examined when estimating the useful life of the fabric. Although there are simple ways to measure such strength, theoretical prediction and modelling continue to be difficult, due to the many variables that contribute to the complicated mechanisms involved in the tearing process [16][17][18][19]. Examples include the development of a del-zone in a tongue tear test (see figure 1).…”