Search results

In order to help explain experimental findings related to the stabbing- and ballistic-penetration resistance of flexible body-armor, single-yarn pull-out tests, involving specially prepared fabric-type test coupons, are often carried out. The purpose of this paper is to develop a finite-element-based computational framework for the simulation of the single-yarn pull-out test, and applied to the case of Kevlar® KM2 fabric.

Three conditions of the fabric are considered: neat, i.e, as-woven; polyethylene glycol (PEG)-infiltrated; and shear-thickening fluid (STF)-infiltrated. Due to differences in the three conditions of the fabric, the computational framework had to utilize three different finite-element formulations: standard Lagrangian formulation for the neat fabric; combined Eulerian-Lagrangian formulation for the PEG-infiltrated fabric (an Eulerian subdomain had to be used to treat the PEG solvent/dispersant); and combined continuum Lagrangian/discrete-particle formulation for the STF-infiltrated fabric (to account for the interactions of the particles suspended in PEG, which give rise to the STF character of the suspension, with the yarns, the particles had to be treated explicitly).

The results obtained for the single-yarn pull-out virtual tests are compared with the authors’ experimental counterparts, and a reasonably good agreement is obtained, for all three conditions of the fabric.

To the authors’ knowledge, the present work represents the first attempt to simulate single-yarn pull-out tests of Kevlar® KM2 fabric.

The purpose of this paper is to predict the pull-out force of loop pile of ramie/cotton terry woven fabrics treated with aroma-microcapsules as well as to understand and to interpret the pull-out behaviour developing the mathematical model.

The displacements and forces associated with pulling a yarn from different structures of fabrics were determined. Regression analysis and factorial designs were performed.

The yarn pull-out behaviour of terry fabric is highly dependent on the applied treating and demonstrated various extents of variability under the different pulling distances. The character of yarn pull-out is periodic and depends on fabric construction. The difference between the resistance to pile loop extraction for the grey and modified terry fabrics depends on the changed fabric’s structure. The existence of good relation between binder’s concentration and resistance to pile loop extraction of terry fabric was proved.

The study enables to forecast important loop feature for terry aroma-textiles: to be securely held in the place preventing loop pulling.

The assessment of the influence of fabric’s weft density and binder’s concentration for the yarn pull-out of terry aroma-textile was proposed. The research developed analysis and empiric mathematical equations suitable for predicting of displacements and forces related to pulling phenomenon as well as designing new multifunctional terry fabrics with resistance to pile loop extraction required. The received knowledge could enlarge the base of information needful for design of new products for clothing, home textile and healthcare/well-being applications as well.

The aim of this study was to understand the stick-slip properties of single and multiple yarn pull-out in dry and treated polyester satin woven fabric in boundary regions.

Polyester satin pattern woven fabric was used to conduct the pull-out tests in order to examining the kinetic region of the force-displacement curve. Data generated from this research help the authors to obtain stick-slip force and accumulative retraction force.

It was found that stick-slip force and accumulative retraction force depend on the number of pulled ends in the fabric, fabric sample dimensions and softening treatments. Stick-slip forces of polyester satin fabric in the multiple yarn pull-out test were higher than those of the single yarn pull-out test. Stick-slip force in single and multiple yarn pull-out tests in the dry polyester satin fabric was generally higher than those of the softening treated polyester satin fabric. In addition, the warp directional single and multiple yarn stick-slip and accumulative retraction forces in the dry and softening treated polyester fabrics were generally higher than those in the weft direction in the fabric edges due to fabric density. On the other hand, the amount of stick-slip force was related to the number of interlacement points in the fabric, whereas the amount of accumulative retraction force was related to fabric structural response.

The mechanism of stick-slip and accumulative retraction force of dry-treated polyester satin pattern woven fabrics were explained. This research could be valuable for development of multifunctional fabrics in technical textiles and ballistic.

The purpose of this paper is to investigate the resistance to pile loop extraction of terry fabrics regarding the pile height and impact/finishing.

Fabrics are manufactured by changing the pile height and applying impact/finishing procedures. The resistance to pile loop extraction are determined. The factorial designs are made. For informative experiment the linear type of regression are analysed. Yarn pull-out behaviour in terry fabrics is discussed.

The dynamics of yarn pull-out process in terry fabrics is estimated through the force-pulling distance curves presented. The resistance to pile loop extraction is determined. All statistical analysis is performed. Appropriate conclusions about the influence of fabrics structure and impact/finishing on yarn pull-out process are made.

The study developed analysis and empiric mathematical equations suitable for evaluating and designing fabrics with the resistance to pile loop extraction ability required. Assessment of the influence of fabric's pile height and impact/finishing on the yarn pull-out is proposed.

Para-aramid fabrics see service in a great variety of applications, such as heavy weight lifting applications, penetration protective multilayer panels, etc. It is, therefore, increasingly important to understand the strain rate range at which the fabric has optimum mechanical properties. Although this is a field that has not been studied before, it is of great significance since it allows for the determination of the fabric’s layer location within the multilayered structure which offers maximum overall performance. The paper aims to discuss this issue.

Rectangular strips of PARAX 300 S8 woven para-aramid fabric underwent uniaxial tensile tests at various extension rates. The angle between two fibers at the center of each specimen was measured after the fabrics were elongated at different tensile extensions. This recovery angle was determined by visual analysis of the test video recordings after specimen unloading. Based on this, the recovery of the weaving form after unloading was also estimated for each tensile extension. A recovery degree based deformation characterization of the sections of a typical load/extension curve has been introduced.

The fabric does not appear to be strain rate sensitive for a strain rate range of 0.03 s-1 to 0.53 s-1, and its load/extension characteristics are generally not affected by the extension rate. However, break load and maximum elongation values appear reduced at actuator velocity of 2,400 mm/min and enhanced at 3,600 mm/min. Finally, the effect of extension rate on the different deformation zones of the material is reported and discussed.

The current research work offers a novel approach for the investigation of non-standard response of woven para-aramid fabrics when subjected to tensile loading under various strain rates. Additionally, a new approach is introduced to explain in detail the deformation zones based on the recovery degree of the fiber orientation angle after unloading.

The purpose of this paper is to clarify how the micro-structure and -properties of wool fibers influence the pilling property of woolen fabrics.

The fuzzing and pilling property of woolen fabrics was investigated, based on micro-scale including basic structural characteristics of wool fibers, wool scale topography and surface friction, etc. Scanning electron microscope was used to analyze wool fiber structure; frictional coefficients were measured by capstan method. Then three different kinds of wool fibers are spun into yarns, then knitted into woolen fabrics, whose pilling grade were estimated by means of Pillbox method.

Results show that the finer the fiber, the fabric pilling degree will be higher; the shorter the fiber, the fabric’s pilling is more serious; the number of pilling is decreasing with the increasing number of crimp; the longer the scales, the better anti-pilling property of fabrics, while the larger the scale thickness, the worse the anti-pilling property; and initially, with the increasing DFEs, fabrics are not easy to pilling, however, there exists a critical value.

Fuzzing and pilling property of woolen fabrics are affected by number of factors, including raw fibers, yarns, fabric tissue and finishing process, etc. In this paper, the authors exclude the influence of yarns’ parameter and fabrics’ tissue, etc., but focus on the micro-structure and -properties of raw wool fibers; and establish a direct connection between fabrics’ pilling property and fibers’ parameters.

Occurrence of fabric rupture is a problem that can influence fabric performance during wear. In this regard, fabric tearing resistance is considered by manufacturers and consumers and enhancing tear resistance through optimization of related parameters is beneficial.

In this study, the tearing resistance of a series of shirting fabrics with various weave patterns and weft densities were investigated by both static and dynamic tear test methods. Moreover, the constituent yarn's frictional and tensile behaviour was evaluated and their relation with tear resistance was analysis.

According to the outcomes, the fabric firmness and density and friction of yarns affect the tear resistance, reversely. However an improvement in yarn's tenacity can raise the tear resistance.

In this study it was aimed to not only consider influence of both static and dynamic tear test approach on the tearing performance of fabrics regarding their structural parameters, the impact of the constituent's yarn properties include tensile behaviour and friction coefficient on the tearing performance of fabric considered, as well.

This research seeks to investigate the potential of using para‐aramid fibre fabric and yarn as an external reinforcement to existing structures. The purpose of this paper is to improve existing structural performance or to return the original design performance, during refurbishment. The research aims to investigate the potential for enhanced flexural strength and toughness in concrete beams, which may be required for change of use of buildings, where loadings may be subject to change. Buildings in earthquake zones may also benefit from additional toughness provided with external fabric/yarn reinforcement as a means of providing additional time for escape, for the occupants.

The test compared four types of concrete beams with different reinforcement material compositions and each set consisted of three beams. The beams were: plain reinforced concrete without any external form of reinforcement (RC), plain unreinforced beams with a para aramid sheet (KF), plain unreinforced beams with para aramid strips of yarn attached longitudinally (KY) and plain reinforced concrete beams with sheet fabric (RCKF). All of the para‐aramid material (fabric and yarn) was externally bonded to the samples, using a two part epoxy resin adhesive applied to a prepared surface. To determine the flexural strength and toughness a three point loading test was used to provide load and deflection data on the 12 (500 mm×100 mm×100 mm) concrete beams.

An increase in flexural strength and toughness was observed when para‐aramid was used in conjunction with steel reinforcement bar (re‐bar). The para‐aramid fabric and yarn produced similar results to the plain reinforced concrete beam in terms of flexural strength but not toughness.

An advantage of using para‐aramid as an external reinforcement, would be to utilise the large deflection the beam sustains under loading, whilst the fabric/yarn holds the beam together across the rupture plane. Although the testing did not prove that para‐aramid would be a viable alternative to steel re‐bar it did show that the material has the potential as an additional reinforcement that may be particularly useful where concrete structures are subject to large deformations or in need of repair.

This paper aims to assess the relationships amongst the tearing strength of fabrics after each chemical processing stage and after finishing of plain-woven cotton fabric. An effort has been made to study the effect of different finishing chemicals (tear improver) and their different concentrations on the high-density fabric tear strength and its sub-component with respect to the co-efficient of friction value of yarns for all the fabric samples. It also aims to establish a statistical model for prediction of tear strength with identified parameters as yarn–yarn friction co-efficient, yarn pullout force and single yarn strength.

In case of woven fabrics, it cannot be assumed that only yarn friction plays the role in deciding fabric-tearing strength. Whether the static or kinetic frictions need to be considered or the linear or capstan frictions have to be analyzed, to incorporate the results of friction analysis in the tearing behavior, need to be assessed. In the present work through a fabrication of yarn–yarn friction measurement, under a synchronized slow speed as that of actual fabric tearing (50 mm/min), has been carried out. After each wet processing stage, surface characteristics of yarns have been changed. Surface of yarns becomes smoother after finishing and rough after dyeing, which affects the co-efficient of friction of yarns, accordingly.

After each wet processing stage, the surface characteristics of yarns are changed. Surface structure of yarns becomes smooth after finishing and rough after dyeing, which affects the co-efficient of friction of yarns. For all the fabrics, the weft-way tearing strength is always higher than warp-way tearing strength. It is also observed that yarn pullout force is not the only responsible factor for tearing strength of such fabric. It is because of the combined action of yarn–yarn friction, yarn pullout force and single yarn strength for a given structure.

A more extensive investigation with respect to concentration as well as further variety of chemicals requires to be identified for the optimum concentration level for each chemical. A mathematical model based on the three parameters as yarn–yarn co-efficient of friction, yarn pullout force and yarn strength for all woven fabric structure to achieve optimum strength level has been established which could be further extended for each fabric structures.

The problem has been identified from the day-to-day exercise of the commercial textile industry. The whole of the sample preparations have been done in the industry by using commercial machines under standard industrial conditions. The findings have been discussed and suitably introduced in the industry.

The whole of this paper has been unique in idea origination, sample preparation and execution of tests. The findings are very important for the researchers as well as for textile industry.

In recent times, the usage of elastane-containing denim garments has increased, as it provides fit and comfort both at the same time. The purpose of the study is to understand the effect of abrasion on the durability of comfort related to body movement and shape retention property of the stretch-denim fabric.

The paper investigates the effect of abrasion on the initial tensile properties, recovery and resilience properties of the stretch-denim fabric. Further, to analyse the effect of the composition of the elastane yarn, three different types of elastane yarns having different types of sheath (covering) fibre, structure and different levels of elastane content have been used in the weft.

The comfort related to body movement and the shape retention properties of the stretch-denim fabric got affected due to abrasive damage. The elastane yarn composition and structure played an important role in determining the extent of the change in such properties during abrasion. The fabric with a higher level of elastane content suffered a greater loss in shape-retention properties due to abrasion. The extent of mass loss in stretch-denim fabric does not always correlate to the extent of loss in the comfort and shape-retention properties.

Most of the earlier studies have investigated the effect of abrasion on the durability aspect of the stretch-denim fabric. In a practical scenario, the stretch-denim garments are rarely discarded due to tearing or change in appearance but mainly due to bagging, i.e. distortion in shape after usage. Thus, the study on the combined effect of the abrasion and cyclic loading on the comfort and shape-retention properties will help to predict the performance of the apparel during usage.