Jacqueline R. Postle and Ron Postle
There has been much discussion in the literature about the relationship between fabric “handle” and objective instrumental measurements of fabric low stress mechanical and surface…
Abstract
There has been much discussion in the literature about the relationship between fabric “handle” and objective instrumental measurements of fabric low stress mechanical and surface properties such as fabric tensile properties, shear, bending, lateral compression, surface friction and surface roughness. But fabric “handle” is not really an inherent fabric property, rather it is a description of one of the ways in which people generally make a subjective assessment of some of the quality attributes of apparel fabrics, designed for particular end‐use applications. In contrast, fabric drape is an inherent mechanical property of a fabric. Fabric drape is that unique property which quantifies the ability of a fabric to bend simultaneously in more than one plane. In order to exhibit the property of drape, fabrics must be able to bend and shear simultaneously, thus distinguishing textile materials from paper or thin polymer films. Develops a fundamental mechanical analysis of fabrics bending under their own weight. The equations governing the shape of an elastic fabric cantilever are solved numerically. Discusses the implications for experimental measurement of fabric bending length and fabric bending rigidity in terms of these numerical solutions with negligibly small errors. Graphically presents profiles of the draped fabric cantilever. Makes a comparison of the numerical solutions with the approximate formulae derived by F.T. Peirce.
Details
Keywords
Jacqueline R. Postle and Ron Postle
Aims to analyse unique deformation properties of textile materials in terms of basic mechanical properties. Models fabric deformation as a nonlinear dynamical system so that a…
Abstract
Aims to analyse unique deformation properties of textile materials in terms of basic mechanical properties. Models fabric deformation as a nonlinear dynamical system so that a fabric can be completely specified in terms of its mechanical behaviour under general boundary conditions. Fabric deformation is dynamically analogous to waves travelling in a fluid. A localized two‐dimensional deformation evolves through the fabric to form a three‐dimensional drape or fold configuration. The nonlinear differential equations arising in the analysis of fabric deformation belong to the Klein‐Gordon family of equations which becomes the sine‐Gordon equation in three dimensions. The sine‐Gordon equation has its origins in the study of Bäcklund Transformations in differential geometry. Describes fabric deformation as a series of transformations of surfaces, defined in terms of curvature parameters using Gaussian representation of surfaces. By considering a deformed fabric as a two‐dimensional surface, algebraically constructs analytical solutions of fabric deformation by solving the sine‐Gordon Equation. The theory of Bäcklund Transformations is used to transform a trivial solution into a series of solitary wave solutions. These analytical expressions describing the curvature parameters of a surface represent actual solutions of fabric dynamical systems.
Details
Keywords
Sajal Kumar Chattopadhyay and Bindu Venugopal
Most researchers have neglected the effect air-drag force on yarn tension during rotor spinning. This paper aims to study the effect of rotor air-vacuum pressure in conjunction…
Abstract
Purpose
Most researchers have neglected the effect air-drag force on yarn tension during rotor spinning. This paper aims to study the effect of rotor air-vacuum pressure in conjunction with opening roller speed and yarn linear density on the yarn tension generated during the rotor spinning, which has established their significant influences on both the mean and the peak tension.This is the first of one-of-a-kind experimental study being reported to demonstrate the influence of air-drag force on yarn tension during the rotor spinning under dynamic condition.
Design/methodology/approach
The dynamic measurements on yarn tension at the exit of the doffing tube were carried out by using an electronic capacitive yarn tension meter during rotor spinning. The derived experimental data were fitted into equations to construct the response equations and to work out the coefficients of multiple correlation between the data and the predicted equation for both the mean and the peak tension. Various surface plots were constructed by using those response surface equations, so as to study the effect of variables on yarn tension generated during the rotor spinning.
Findings
The study has established that the rotor vacuum is responsible in causing a change in yarn tension, it increases with the decrease in air-vacuum inside the rotor. The involvement of the opening roller speed in altering yarn tension during rotor spinning has been proved. As the opening roller speed changes, so does the air stream surrounding the opening roller speed with consequent alteration of the centrifugal force generated due to the rotation of the rotor. The centrifugal force and, hence, the yarn tension generated in the rotor will be simultaneously affected by both the rotor relative vacuum and the opening roller speed.
Research limitations/implications
This is a structured experimental study to verify the influence of air-drag force generated during rotor spinning on yarn tension. Very limited theoretical work has been carried out in this direction as reported in the introductory part of the paper. The result of the present study will encourage future researchers to revisit the theory on generation of air-drag force during rotor spinning and work out a new formula.
Practical implications
Next only to the conventional ring spinning system, the rotor spinning holds the second place in the share of global yarn production. Because of its advantage of lower cost of production and amenability to automation, the rotor spinning has gained acceptance in spun yarn production, particularly for spinning coarse and medium counts of yarns. Currently, it has acquired about 25 per cent share in the world’s spun yarn production. As many of the rotor machine variables significantly affect fibre configurations and, subsequently, the yarn properties by influencing the airflow characteristics inside the rotor unit, the study of yarn tension during rotor spinning and its analysis assumes a significance.
Social implications
Rotor spinning is a relatively new and faster method of conversion of discrete fibres into continuous staple yarn and, subsequently, various textiles and garments. Its yarn is distinct and a bit different compared to the conventional ring yarn. It has got wide acceptance in the market and fashion. As such, the spinning sector that converts fibres into yarns is an important industry world over, providing employment to many. Besides, being the basic operation in the fibre value chain, it supports many downstream activities, including human clothing and fashion. Thus, the research on rotor spinning, particularly the yarn engineering to produce better products will be helpful to strengthen and grow the textile value chain.
Originality/value
This is an original research study. The magnitude and the direction of the air drag on the yarn during rotor spinning is very difficult to assess. Thus, most researchers for the sake of simplicity in analysis have neglected its effect on yarn dynamics, but a few of them have taken note of it in their theoretical propositions. However, no experimental result has been reported so far in the literature, supporting the influence of such air-drag force on yarn tension in the rotor spinning. In fact, none of the above studies have considered the induced effect of centrifugal force caused because of the rotation of the opening roller on the airstream that flows from the transfer channel inlet into the rotor because of its partial vacuum, causing consequential effects on air-drag force and tension in the yarn inside the rotating rotor. This is the first of one-of-a-kind experimental study being reported to demonstrate the influence of air-drag force on yarn tension during the rotor spinning under dynamic condition.
Details
Keywords
A. Alamdar‐Yazdi and J. Amirbayat
Objective measurement of fabric mechanical properties has great potential for quality control of clothing materials. However, access to the requisite instruments still remains a…
Abstract
Objective measurement of fabric mechanical properties has great potential for quality control of clothing materials. However, access to the requisite instruments still remains a problem for many potential users due to their high cost. A new methodology for measuring the basic low stress mechanical properties of woven fabric on a tensile tester is introduced. The results of experimental work on 39 samples are also presented. As a result, new parameters indicating the behavior of woven fabrics are introduced.
Details
Keywords
J.W. Eischen and Y.G. Kim
Uses a general large displacement beam theory to formulate a finite element‐based numerical method for simulating fabric drape, manipulation and contact. Presents numerical…
Abstract
Uses a general large displacement beam theory to formulate a finite element‐based numerical method for simulating fabric drape, manipulation and contact. Presents numerical results corresponding to real fabric materials. Shows a broad class of fabric mechanics problems including how these effects can be solved.
Details
Keywords
F.B.N. Ferreira, S.C. Harlock and P. Grosberg
A study of thread tensions on a lockstitch sewing machine was made, measuring simultaneously both the needle and bobbin thread tensions. Experiments were carried out under…
Abstract
A study of thread tensions on a lockstitch sewing machine was made, measuring simultaneously both the needle and bobbin thread tensions. Experiments were carried out under specified sewing conditions, whereby needle and bobbin thread tensioner adjustment, sewing speed, number of plies, fabric quality and sewing thread quality were varied in order to investigate the effect of these factors on the needle and bobbin thread tensions. The patterns of the thread tension traces obtained were analysed as well as the effect of these factors on the peak tensions detected on both thread tension traces. Four significant peak tensions on the needle thread tension trace and two significant peak tensions on the bobbin thread tension trace were detected, during a stitch cycle. It was found that no significant variations occurred as far as the timing and shape of the peak tensions were concerned. However, variations were detected in the peak tensions according to the sewing conditions, as expected. From the analysis of the data obtained, multiple regression equations were derived to predict, with a good degree of accuracy, the peak tensions generated, according to the sewing conditions.
Details
Keywords
F.B.N. Ferreira, S.C. Harlock and P. Grosberg
The purpose of this investigation was to try to develop a theoretical model to satisfy and explain the interaction between the needle and bobbin threads, the tensions developed…
Abstract
The purpose of this investigation was to try to develop a theoretical model to satisfy and explain the interaction between the needle and bobbin threads, the tensions developed and their influence on seam balance. An explanation of the conditions determining seam balance is proposed based on a “robbing back” theory of stitch formation.
Details
Keywords
F.B.N. Ferreira, S.C. Harlock and P. Grosberg
A study of thread tensions on a lockstitch sewing machine was made, measuring simultaneously both the needle and bobbin thread tensions. Investigates the relationship between the…
Abstract
A study of thread tensions on a lockstitch sewing machine was made, measuring simultaneously both the needle and bobbin thread tensions. Investigates the relationship between the peak tensions generated during the experiments and the corresponding seam balance. It was found that under the conditions of the experiments it is possible to define an envelope of conditions under which balanced seams will be obtained.
J. Ascough, H.E. Bez and A.M. Bricis
Uses Newmark’s method to carry out a time‐stepping finite element analysis to predict the behaviour of a cloth garment as it falls from an initial horizontal position to a final…
Abstract
Uses Newmark’s method to carry out a time‐stepping finite element analysis to predict the behaviour of a cloth garment as it falls from an initial horizontal position to a final position draped around a human body form. Bases the finite element model on a simple beam element, in order to minimize the computational time. Accounts for large displacement behaviour by including the element geometric stiffness. Bases the body form on anthropomorphic data produced by a shadow scanner. Enlists a novel scheme to model the contact between the cloth and the underlying body form. Uses the finite element model to provide data for an animated display and finds that it produces sufficiently realistic results for the garment designer’s purposes.
Details
Keywords
Inter-fibre cohesion is regarded as an important property of assemblies, such as slivers, made of wool or any other fibres, with respect to the processing in carding, drawing…
Abstract
Inter-fibre cohesion is regarded as an important property of assemblies, such as slivers, made of wool or any other fibres, with respect to the processing in carding, drawing (gilling) and spinning. In this paper, the results of the multiple regression analyses, and their validation, are presented to show that a strong relationship exists between the sliver cohesion (measured as sliver tenacity and sliver specific energy-to-break in a long-gauge tensile test) and a combination of the standard wool properties, such as bulk, mean fibre length (Barbe), mean fibre diameter and medullation content, used for the objective blend specification of New Zealand wools for marketing and processing.