Objective Evaluation of the Handle of Woven Terry Fabrics
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Volume 9, Issue 3, 2015 Objective Evaluation of the Handle of Woven Terry Fabrics Diana Krasteva, Deputy Head of Department, Textile Department Technical University of Sofia Galya Kandzhikova Textile Department Technical University of Sofia Bulgaria ABSTRACT The aim of the work is development of a methodology and an integrated assessment for objective evaluation of terry fabric handle. They should meet the following criteria, which will allow to use them not only in scientific researches, but also in the quality control of products in manufacturing plants: to be based on standardized methods or universal appliances, the assessment to be easily calculated and to comply with the most common scale for handle evaluation – that of Kawabata. The integrated assessment is derived my means of the multiple regression analysis and includes six characteristics of terry fabrics that have a proven impact on handle: thickness, relative compression at pressing, bending stiffness, coefficient of elasticity at tension, coefficient of elasticity at shearing and dynamic coefficient of friction. The assessment obtained corresponds to the subjective one. The methodology for evaluation is worked out as a draft standard. A software application for automatic computation of the assessment is developed. It runs under Windows, does not require installation and is easy to use. Keywords: integrated assessment of handle; objective evaluation; woven terry fabric; standard method Introduction The first attempts to evaluate the Handle is one of the important handle of textile products date back to 1926, quality parameters for textile products. There when Binns set the beginning of systematic is no consumer who, when buying clothing, subjective evaluation (Binns, 1926). interior textiles or when evaluating the Subsequently, many authors have contributed upholstery of a car, has not touched the to both its subjective and objective product to see what it feels like. measuring, starting from Peirce (Peirce, 1930) who first suggested the evaluation to Article Designation: Refereed 1 JTATM Volume 9, Issue 3, 2015 be carried out by measuring the physical and The fabric handle can also be mechanical properties, through Kawabata evaluated through the resistance that a and Niwa (Kawabata, 1980; Kawabata & sample shows when inserting it into a slot Niwa, 1991, 1998), Postle (1990), Pan (Pan using a beam et al., 1988a, 1988b, 1993; Pan, 2007) and (www.thwingalbert.com/handle-o- many others (Matsudaira, 2006; Singh et al., meter.html). The resistance is function from 2014; Sztandera, 2008a, 2008b; Zeng, 2004). the sample’s flexibility and surface friction. Some of the investigations led to the Despite the availability of numerous development of devices for objective methods and devices for evaluating the measurement of the handle, such as KES handle, the method of Kawabata remains the (Kawabata's Evaluation System), FAST most prevalent. Applying his approach, a (Fabric Assurance by Simple Testing), number of translational equations for PhabrOmeter System, Handle-O-Meter, etc., different types of fabrics have been derived. and other - to the development of models for The importance of the handle for integral evaluation of handle for different terry products is huge (Yilmaz & Powell, textiles products. 2005), but such relations for this class of Globally, the most widespread is the fabrics have not been developed yet. Most system of Kawabata. From the measured studies examine some aspects of the problem. characteristics through regression models, A more complex approach was applied by the so-called THV (Total Hand Value) is Frontczak-Wasiak and Snycerski, who determined, which is based on the subjective suggest the use of radial diagrams for ranking evaluation of handle and is respectively of fabrics according to their handle. influenced by the social and geographical However, the authors do not suggest a situation of the experts Pan (Pan et al., numerical evaluation (Frontezak-Wasiak & 1988a). Most often, linear or combined Snycerski, 2004). linear-logarithmic models are used for its calculation. In 1990, a similar system – the 2. Experiment FAST of CSIRO (Tester & Boos, 1990) appeared. It is simpler, realizes only semi- The aim of the investigation is cyclical loads and the handle can be assessed development of a methodology for evaluation by the so-called finger print. of terry fabric handle. In order to be applied To avoid the subjectivity, Pan in manufacturing plants also, it should be proposed the determination of THV to be relatively simple and therefore, the following done objectively by application of the requirements were set: Weighted Euclidean Distance (Pan, 2007). It use of devices, which are universal or represents the deviation of the sample from a inexpensive; standard set in n-dimensional space where easy calculation of the integrated each axis is an objectively measurable assessment; property. The particular properties and their comparability of the assessment with number vary by the different authors (Pan, existing rating scales. 2007; Sztandera, 2008a, 2008b). The device PhabrOmeter The approach of Kawabata was used as well (www.phabrometer.com/FAQ/pgeDefinition as the scale proposed for evaluation of the .aspx) works using this method, as well as handle quality. The investigation process was many other devices and stands where the carried out in the following steps: force at extraction of a circular sample (1) Determination of the properties through a nozzle or ring is measured. The characterizing terry fabric handle and basic parameters involved in the evaluation their ranking according to the degree of handle are taken from the curve of influence. For this purpose, an force/displacement. inquiry was developed and a survey among specialists was conducted. Article Designation: Refereed 2 JTATM Volume 9, Issue 3, 2015 Obtained results were processed by the Krasteva, 2015). They show that experts rank method of rank correlation. the criteria for evaluation of terry fabric (2) Conduction of a subjective evaluation handle according to their degree of influence of the handle of terry fabrics. It was in the following order: bulkiness, thickness, conducted by specialists and smoothness, stiffness, elasticity and consumers under Evaluation Procedure elongation. The bulkiness was evaluated by 5 – Handle of Fabrics: Guidelines for the characteristics mass per unit area and rate Subjective Evaluation (AATCC of compression, the stiffness – by bending Evaluation Procedure 5). Fabrics with stiffness and shear stiffness, and the different structural features and smoothness – by the coefficient of friction. finishes were examined. (3) Development of a methodology for Step 3 testing and evaluation of terry fabric For the characteristics specified in the handle. An analysis of the existing previous step, methods for their methods for determining the properties determination were selected or adopted. characterizing the handle was performed, and the methods, devices Mass per unit area and tools according to the requirements The mass per unit area of textile set were chosen. Examinations were fabrics is determined according to the conducted to establish the appropriate European standard EN 12127:2000. The conditions for testing of terry fabrics. method is suitable for terry fabrics and is (4) Objective measurement of the cited as reference in EN 14697:2006 Textiles properties influencing the handle. The - Terry towels and terry towel fabrics - determination was performed in Specification and methods of test. The mass accordance with the selected methods, per unit area is determined for 5 samples with devices and test conditions. an area of 100 cm2, and is recalculated for (5) Deriving a mathematical model for square meter. calculation of a numerical assessment of terry fabric handle. By multiple Thickness and compression rate regression analysis, relationships The methods for determining the between subjective assessments and thickness and the rate of compression vary objectively measured properties according to the test conditions. In most characterizing the handle were derived. cases, the test is semi-cyclical (the FAST Different combinations of input system and conventional thickness gauges). parameters were tested. The adequacy In the KES-F system it is single-cyclical and of the models was examined and based allows the determination of the degree of on a certain requirements a model for recovery after compression. Preliminary calculation of the integrated handle experiments were carried out - deformation assessment was selected. curves were drawn for various terry fabrics (6) Model validation. A validation of the by variation of the pressure from 0.1 kPa to mathematical model through further 10 kPa. examination of woven and nonwoven The method standardized with EN stitch-bonded structures was ISO 5084:2002, in which the area of performed. compression is 20 cm2, and the levels of load (7) Drawing up the methodology as a – 0.1 kPa and 1 kPa, was selected. It was standardization document. proved that the chosen values are suitable for terry fabrics. Steps 1 and 2 The compression rate ZRx was defined in The results of the first two steps are percentage according to DIN 53885:1998-12: presented in a particular publication of the research team (Kandzhikova & Germanova- Article Designation: Refereed 3 JTATM Volume 9, Issue 3, 2015 ZAx ax a10x Based on the first method works the ZRx .100 100, (1) module B2 of the system KES-F, as the ax ax moment is measured as a