Detection of Fabric Structure Irregularities Using Air Permeability Measurements

Abstract

In this paper we demonstrate the possibility of using the close relationship between structure and air permeability of a woven fabric for the detection of the non-uniformity (or defects) in the structure of the fabric. Air permeability of fabrics is a principal property of the structure of a textile material. A very small change in the structure of the fabric at a given location causes a change in the permeability at that location. First we measure the air permeability at defined locations of the fabric. The method allows us to detect areas with an extreme value of permeability – the locations “suspected” of extreme unevenness of fabric's structure. Second, we explore the structure of the fabric in these areas of extreme values of the permeability and attempt to determine the causes of the irregularities in the fabric's structure. To quantify and describe the degree of these irregularities we applied methods of image analysis and statistical processing on acquired data. For our experiment, woven fabrics in the plain weave made from 100% staple yarn polyester were used. Results of our research confirm that significantly greater permeability variations occur in the weft direction of the fabric. Subsequent analysis of the structure of the fabric shows the bimodal nature or the data corresponding to the measurement of width of inter-yarn pore in the place of the maximal value of permeability. The observed higher value of permeability can be attributed to the irregularity of warp yarns at a given location of fabric. Initial permeability measurements enabled us to detect locations of its extreme values. Further close examination of these “suspected” locations of the fabric by a detailed analysis of the structure lead to the determination of the causes of the related irregularities.