Showing papers in "Journal of The Textile Institute in 1991"

Drape Prediction by Means of Finite-element Analysis

Abstract: The draping behaviour of fabric treated as an orthotropic shell membrane is predicted by using a geometric non-linear finite-element method, and the results are compared with actual behaviour. A drape tester employing photovoltaic cells was designed and constructed to determine the drape coefficient of fabric specimens of 10-in. diameter. The warp- and weft-direction tensile moduli of these samples were determined by using a Kawahata Tensile and Shear Tester, and literature values of Poisson's ratio were obtained. With this approach, excellent agreement between experimental and predicted drape coefficients resulted. For a 100% cotton plain-weave fabric, a drape coefficient of 68.4% was experimentally determined as compared with a predicted value of 71.0%.

A Stochastic Model of the Apparel-retailing Process for Seasonal Apparel

Abstract: A computer model is described that simulates the seasonal apparel-retailing process. The model is stochastic in nature and is designed to allow the investigation of the effects of improved retailing procedures on financial and other performance measures. Its principal value lies in the evaluation or Quick Response (QR) supply methodologies that allow frequent re-estimations of consumer demand and reorders of merchandise based on in-season point-of-sale (POS) data at the stock-keeping-unit (SKU) level.

A Comparison of Linear and Non-linear Bending Models for Predicting Fabric Deformation in Automated Handling

Abstract: The problem of simulating the laying of fabric on a table is studied in this paper. The non-linear bending properties of fabric are defined by interpolating the moment/curvature relationship measured with the Kawabata system. By using a linear and a non-linear bending model, deformed fabric shapes are predicted and compared with experimental data. The predicted fabric curves agree well with experimental curves. Results show that the non-linear bending model is superior to the linear bending model in predicting the deformation of fabrics with nonlinear bending properties. Both linear and non-linear models can perform equally well in predicting the deformation of fabrics with linear bending properties. The numerical stability of the differential-equation system used in this study is also analyzed. We show that the non-linear model improves the stability of the computational process.

Predictability between objective physical factors of fabrics and subjective preference votes for derived garments

Abstract: The relationships have been investigated between subjective preference votes, collected under three different conditions, for garments derived from a range of fabric materials and objective physical factors (where “factors” are grouped properties) measured for the same materials. The technique of canonical correlation analysis was applied, and three canonical correlations between subjective preference votes and objective physical factors were found to be highly significant (P 0.950). Canonical redundancy analysis showed that the objective physical factors of fabrics had great predictive power for the subjective votes, with cumulative redundancy over 0.983. The subjective preference votes, however, were poor predictors for the physical factors of fabrics, with cumulative redundancy only 0.467. The squared multiple correlations suggested that the first three canonical variables of the objective factors of fabrics had very good predictive power for all three subjective preference votes, but the...

Fiber Assembly in Friction Spinning

Abstract: Both classic and novel research methods were used to study a number of questions concerning the mechanisms involved with fiber assembly in friction open-end spinning of cotton yarns. The equipment used was a much-modified DREF-3 friction-spinning unit with replaced suction rolls and equipped with a comber-roll assembly from a Platt 881 rotor-spinning unit Reynolds-number simulation in a water medium provided a means of determining the source of flow instabilities in the vicinity of the nip. Considerable energy losses were found as a result of flow inefficiencies in the inner cylinders, and methods of improving the cylinder design were suggested. The use of short-duration flash techniques provided a means of determining fiber orientation prior to accumulation and assembly on the yarn tail. These techniques made it possible to photograph the yarn tail forming as well as the gradual tightening of the structure upstream of the original yarn-forming position. Determination of mechanisms of capture of the fiber...

The Progressive Deterioration of Textile Materials Part V: The Effects of Weathering on Fabric Durability

Abstract: The effects of simulated weathering on the tensile strength, tear strength and abrasion resistance of four single-fibre and two blended fabrics are investigated by using the Weather-Ometer tester with xenon-arc exposure and a standard wetting procedure. Results show general similarity of behaviour with Individual variations, molecular bonding explanations being suggested. Exceptions to the generalisation include variations in rate of degradation, an initial delay before degradation begins, and even an increase of property in the early stages of treatment; fabric structural factors may be responsible for this deviation. Although the degradative treatment was not continued to the end of fabric life, there are indications that mathematical analysis of the pattern would show that most fabrics are likely to have extended ‘risk times’ in use, and would require early retirement in critical applications.

The Dynamic Mechanical Response of Carpets: An Alternative Measurement Technique

Abstract: The dynamic-compression properties of carpet are expected to play an important role in their mechanical performance, but it is difficult to measure these properties at frequencies and pressures corresponding to those occurring in carpet wear. A new vibration technique has been developed which enables the dynamic modulus and damping loss of a carpet lo be measured at pressures comparable to these imposed in carpet wear. The technique involves supporting a vibrator on a soft spring and allowing it to activate a pressure plate resting on the carpet. The results obtained are in agreement with previously published data but relate to a pressure range which is more relevant to carpet wear. Measurements are made at a static pressure of 22 kPa, a dynamic pressure of 1 kPa, and frequencies in the range 200–600 Hz.

International Trade in Textiles and Clothing

Abstract: How is it that by 1988 Germany, acknowledged to be a high-cost producer, was the world's largest exporter or textiles and the fourth-largest exporter of clothing; indeed, that among the top exporters of textiles there were four E.C. countries and the U.S.A. jostling for position with China, Japan, South Korea, and Taiwan, with a similar situation in clothing? Why is it that the lowest-cost producers do not oust the high-cost producers? Is this the result of the Multi-fibre Arrangement, under which the industrialized countries of North America and Western Europe have imposed quota restrictions on imports from developing countries? These questions will be addressed in this survey of international trade.

A Study of Double-rove Yarn Hairiness in the Short-staple-spinning Sector

Abstract: A factorial-analysis technique is applied to study the effects of strand spacing, twist, and spindle speed on the hairiness of double-rove yarn. A wide range of twist levels and spindle speeds is covered by spinning yarns from two different types of fibres, namely, cotton and a polyester-fibre/cotton blend, in order to study the interactions of the chosen variables under the extreme conditions. The results are discussed and compared with earlier findings on singles-yarn hairiness.

The Buckling of Flexible Sheets under Tension Part I: Theoretical Analysis

Abstract: The paper discusses the factors affecting the buckling of flexible sheets under tension that occurs when the external loads are not uniformly distributed. It goes further to analyse the energies involved and gives the criteria for the sheets' instability in terms of dimension less quantities formed from material properties and the sheets' dimensions.

Skin Sensations Perceived in Apparel Wear Part I: Development of a New perception Language

Abstract: This paper describes an expanded method for textile comfort studies using ‘Human Perception Analysis (HPA)’. HPA is a sensory evaluation technique to visualize human responses from stimulation using peer language. The perceptions and sensations of humans can be detected by using specially selected descriptors in a rating sheet The technique is particularly effective for quantifying subjective measurements in garment comfort studies. The procedures used to collect peer language for defining a comfort rating sheet is discussed with different kinds of sleeves. HPA. techniques are illustrated with application of this new method in a pilot comfort study with nylon and cotton fabrics when worn under various conditions.

Bending of Internally Reinforced Rayon Fibers

Abstract: An investigation is reported in which internally reinforced fibers were produced with a skin of rayon and cores of previously oriented nylon, polypropylene, and polyester fibers. The tensile mechanical properties and the moisture-regain characteristics are shown to be decoupled from each other, with the core controlling the tensile properties and the skin dominating the moisture regain. In this study, the dominance of the core on mechanical properties is demonstrated to include additionally bending rigidity, hysteresis, and work recovery. A Kawabata Pure Bending Tester was used with an adapted method for measuring the bending characteristics of individual fibers. The measured fiber-bending properties obtained by using the Kawabata unit are also shown to be consistent with other bending-measurement techniques and with tensile properties.

The Development of Knitted Structures for Filtration

Abstract: Textile niter sleeves for industrial dust-collection purposes are traditionally manufactured from woven and needlefelt constructions. Knitted fabrics have not been seriously considered for use as filter media because of their high extensibility and anisotropy when subjected to the forces that are involved during filtration. This paper is concerned with the development and evaluation of a number of novel single-jersey circular-knitted structures for dust-filtration applications, with particular reference to their performance with regard to the pressure drop, pressure-drop stabilisation, dust-emission level, and filtration efficiency. The mechanical and filtration properties of these single-jersey structures are studied and compared with those of similar woven and needlefelt filter fabrics. It is demonstrated that the physical as well as the filtration characteristics of these structures are comparable with those of woven and needlefelt fabrics, with added benefits of lower production costs and the fact tha...

The Effect of Dynamic Changes in Doffer Speed on Cylinder Loading

Abstract: During the operation or a cotton card with varying doffer speed, it was, noted that both the cylinder loading and doffer loading varied with the doffer speed. From a theoretical analysis of the loading on the doffer and cylinder during sinusoidal speed changes to the doffer, it is shown that it is possible to determine the effect of sinusoidal speed changes on the dynamically varying fraction of the cylinder material which returns on the cylinder and does not proceed on to the doffer from the experimentally determined variations in cylinder and doffer loading. From the theoretical and experimental results, this dynamically varying fraction is determined and discussed.

Investigation of Combing Forces Part I: Fibre Tension

Abstract: It is likely that much of the fibre breakage occurring in rectilinear combing is closely related to the force or tension experienced by individual fibres, Computer-data-acquisition and strain-gauge techniques have been used to measure directly the forces encountered by individual fibres in the fringe during simulated combing. The effect on these forces of different factors, such as fibre length, combing speed, fringe density, etc., has been established.

The Buckling of Flexible Sheets under Tension Part II: Experimental Studies

Abstract: The paper presents the results of experimental work on the buckling of eighteen suiting fabrics when loaded by a pair of concentrated forces along the centre line. The results support the theoretical analysis given in Part I and show the significance of dimensionless quantities derived by considering the different energies involved.

The Effect of Sley Motion on the Beat-up Force

Abstract: A research tool was constructed to measure the effect of the beat-up action on the beat-up force. The system includes a narrow fabric loom whose sley driving mechanism was replaced by a computer controlled hydraulic actuator; all other loom motions were not changed. By inputting different parameters during the initialization part of the software program, the beat-up timing, speed and even the sley forward position can be altered, without requiring any other mechanical adjustments. Experiments were carried out to measure Ihe effect of the above parameters on the beat-up force and the results are reported.

The Geometry of Weft-inserted Warp-knitted Fabrics Part I: Models of the Structures

Abstract: This paper presents geometrical models of weft-inserted warp-knitted fabrics with tricot and chain-stitch grounds. Equations are derived relating the total run-in per course with the yarn radii, the machine gauge, and the courses per unit length in the machine state.

Subjective Assessment of Wet-raised Woollen Fabric

Abstract: An investigation is reported in which a panel of judges, using visual and tactile skills, assessed a series of milled and wet-raised fabrics for smoothness, softness, and stiffness. It was found that fabric smoothness and softness were clearly related to the amount or raise given to the fabrics.

Concurrent Direct Dyeing and Easy-care Finishing of Viscose and Wool/Viscose Blend Fabrics

Abstract: An investigation is described in which conditions for simultaneous direct dyeing and resin-finishing of viscose and wool/viscose-blend (50/50) fabrics were established. Results obtained indicate that (a) the extent of the cross-linking reaction and dye interaction is determined by the kind of catalyst, the nature of the substrate, and the type of finishing agent; (b) the greater extent of dyeing and cross-linking observed in the presence than in the absence of the wool component is most probably due to the change in fibre structure as well as the incorporation of specific functional groups into the molecular structure of the wool component; (c) the enhancement of dye fixation in the presence of the finishing agent may be attributed to the fixability of the dye used to the substrate backbone through ionic salts, hydrogen bonding, van der Waals forces, physical entrapment by the resin, and/or chemically via the finishing-agent functional groups; and (d) for optimization, it is advantageous to carry out the ...

Technological Developments in the Textile Industry

Abstract: Technological developments in the textile indsutry have been very substantial, particularly over the last three decades, and this paper quantifies and illustrates the impact that these technologica...

Structure/Property Relationships of Poly(ethylene terephthalate) Continuous-filament Yarn

Abstract: Two commercial PET yarns, one as-spun and the other highly crystalline and drawn, were annealed at l8°C under various conditions. Mechanical and thermal-response measurements were made under high transient-heating conditions by using a UMIST-built Universal Fibre Tester (UFT). Differential-scanning-calorimetry (DSC) measurements were also made. A middle endotherm was observed on DSC traces for both the PET samples that had been annealed freely (free to shrink). Further thermo-mechanical treatments of these pre-annealed samples were made and thermal, creep, tangent-modulus, and other mechanical properties are recorded. The experimental results show structural instability in the fibre morphology irrespective of the process histories.

The United States Textile Industry on the Eve of its Third Century

Abstract: The current state of the United States textile Industry is surveyed. The scope of the various sectors of the industry is outlined, and there is a brief review of the major end-uses for textile materials and of the quantities consumed by them. The impact of recent technological developments is assessed, and the effects of changes in the industry structure are discussed. Objectives for the future are stated, and the conclusion is reached that the textile industry is one of the most important industries in the United States and now ranks as a world-class competitor.

Weaving with Constant Beat-up Force

Abstract: A weaving system which can weave with a constant beat-up force is described. It includes a narrow fabric loom whose sley driving mechanism was replaced by a computer controlled hydraulic actuator; all other loom motions were not changed. The system is based on adjusting the sley front position on-line according to the level of beat-up force developed in the cycle. When weaving with this system, the visibility of starting marks is reduced considerably, while the variation of beat-up force during normal weaving is reduced to about one-third of its level when weaving without automatic control of beat-up force.

Yarn Attrition and Hairiness: A Yarn Self-rubbing Test

Abstract: An investigation is reported in which hairiness was measured on 40 yarns of different types before and after a yarn self-rubbing action and hairiness and attrition parameters were analysed. It was found that the maximum hair length detected generally decreased after the self-rubbing action, but the evolution of the hair-length distribution and the increase or decrease of hairiness depended on the fibre type, the yarn linear density, the yarn structure (ring-spun or rotor-spun yarns; singles or two-fold yarns), and the tendency to form pills by attrition, as well as the fall-out of matter during frictional action. Of the attrition parameters, the loss of weight by fibre fall-out is greater in cotton yarns than in chemical-fibre staple-spun yarns; in ring-spun yarns than in rotor-spun yarns; and in singles yarns than in two-fold ones. The nap- or pill-formation tendency is greater in fine and medium singles spun yarns than in coarse and two-fold yarns, but here the nature of the fibre plays an important role.

A Study of Throstle-spun-silk/Raw-silk Core-spun Yarn Part II: Stuffer-tube Motion

Abstract: The importance of stuffer-tube dimensions and motion on yarn regularity when a throstle-spinning system is used is demonstrated. A description is given of some attempts to produce longer yarn without piecing and to improve yarn quality. Yarn properties are discussed in relation to the vertical motion of the stuffer tube.

The Economic Outlook for Textiles and Clothing in the 1990s: Developments in the Textile and Clothing Industry in Japan

Abstract: 1985 marked the first year in which Japan's textile and clothing industry began to depart from its long-assigned role as an export industry. It began to restructure, first of all to provide materials for domestic apparel and household use as well as materials for domestic industries. In the 1990s, priorities will be: (i) to supply specialty and proprietary products that provide greater comfort and utility for apparel and interior-furnishing use in the international market, (ii) to supply materials to domestic industrial firms, and (iii) to rely on imports for the supply of commodity products to the apparel and interior-furnishing markets in Japan. Combinations of new concepts and technology are felt to be certain to produce original merchandise to enable Japan to become a production base for quality products.

A Microscopical Study of Severe Biodeterioration in a Textile Floorcovering: A Case History

Abstract: An exceptionally severe case of biodeterioration in a textile floorcovering is described. Examination by light and scanning electron microscopy reveals unusual detail of the degrading organisms and their effects, some of which have not been reported before to the authors' knowledge. The images and microscopical techniques are compared and the causative circumstances of the degradation considered.