Investigating ballistic impact properties of woven kenaf-aramid hybrid composites

In this study, the ballistic impact performance of woven kenaf-Kevlar hybrid and non-hybrid composites against fragment simulating projectiles (FSPs) was investigated. All the composites were prepared using the hand lay-up technique, method, followed by static load compression. The hybrid composites consist of Kevlar fabric and woven kenaf layers. The results obtained indicate that the energy absorption, ballistic limit velocity (V ₅₀) and failure behaviour of the composites during the impact event were affected by the woven kenaf hybridisation. The additional kenaf layers in hybrid composites resulted in the increase in composites thickness and areal density, thus increased the energy absorption (14.46 % to 41.30 %) and V ₅₀ (5.5 % to 8.44 %). It was observed that the hybrid composites failed through a combination of fibre shear, delamination and fibre fracture in the impacted surface, woven kenaf-Kevlar interface and rear surface respectively. Although the specific energy absorption was lower for the hybrid composites, further investigations need to be carried out to utilise the great potential natural fibres.     

Evaluation of anti-stabbing performance of fabric layers woven with various hybrid yarns under different fabric conditions

Various types of special fibers are used for human body protection, mostly in the form of fiber-reinforced composites. These composites are made of special fibers and matrix resin; however, they are often not comfortable for the wearer due to the lack of flexibility and air permeability. This study focuses on an evaluation of human body protective performance against stabbing for various special fibers such as aramid, basalt, and steel fibers, being utilized in cotton hybrid forms. These hybrid forms are designed to improve wearer comfort, while maintaining adequate anti-stab resistance. Specimens prepared with various fabric densities are tested in terms of anti-stabbing performance, according to the NIJ standard. In addition, we investigate the influence of factors such as fiber type, the number of fabric layers, fabric weight, and fabric density on anti-stabbing performance. Results show that the penetration depth of the impactor, which punctures and protrudes through the specimens, decreases with the number of layers, the thickness, and the mass of the armor sample; however, these factors have different relationships according to the material type. Consequently an objective evaluation of anti-stabbing performance is needed. We suggest an anti-stabbing index that can be applied as a criterion to evaluate the antistabbing performance of various specimens woven with special fibers under different fabric conditions. Using the new index, anti-stabbing performances of various specimens can be compared and raw material and fabric conditions that offer the most efficient anti-stabbing performance can be selected.     

Investigating seamed woven fabric drape using experimental and virtual approaches

The aim of this study was to investigate the drape properties of seamed woven fabric using experimental and virtual approaches. Firstly, the influence of different seams on the fabric drape parameters was analyzed based on bending and draping experiments. Then, a preliminary drape simulation method for seamed fabric was presented using shell finite elements. The models with seams were simplified and separated into shell fabric partitions and seam partitions. The projection images of all models were extracted for calculating the drape coefficient and average radius. Through contrasting of drape profiles and correlate analysis of drape parameters, it shows that the drape properties between simulating and testing are very similar and correlated. Furthermore, their regression formulas of drape coefficient and average radius were given by regression analysis. The work has some helps for further study on evaluating and simulating the garment aesthetic performance in considering of seam’s mechanical properties.     

Investigating the effect of yarn count and twist factor on the packing density and wicking height of lyocell ring-spun yarns

The moisture transport expressed with wicking is one of the most important aspects in clothing science and strongly effects on the quality of clothes. Wicking is a spontaneous transport of liquid driven into a porous system by capillary forces. Furthermore, the packing density has a direct relation with the yarn structure. At the present work, the effects of yarn count and twist factor on the wicking height and packing density of lyocell ring-spun yarns was investigated. Achieving the objectives of this research, an image processing method was developed to determine the packing density of samples. Experimental results were also used to develop a regression model to predict the wicking height based on the packing density, yarn count, twist factor and rising time. The results demonstrated that the correlation coefficient between the predicted and measured wicking height was 0.98 indicating the capability of the presented model to predict the wicking height of lyocell ring-spun yarns.     

The impact of dry and wet cleaning on fabric electromagnetic field shield effect

The aim of this research is to investigate shield effect properties of the fabrics with inox yarns included in the construction, which are used for special professional garments and should protect from electromagnetic microwave irradiation. The investigation was done prior to and after the professional care procedures of dry and wet cleaning in ten cleaning cycles. Shield effect measurements were done on the face and on the back of the fabric, weftwise and warpwise, prior to and after the first, third, fifth, seventh and tenth cycles of dry and wet cleaning, at the frequencies from 0.9 to 2.4 GHz. The results obtained indicated that shield effect of the fabric tested was reduced after professional care procedures, especially so after 5 cycles. The investigations also revealed that shield effect could be considerably enhanced if the inox yarns were incorporated into the fabric in the direction of the warp.     

Investigating impact of converging training walls of the ogee spillways on hydraulic performance

Paddy and Water Environment - Due to their economical and structural aspects, ogee-crested spillways can be constructed and operated in a wide variety of situations. In this study, a...     

High performance flame-retardant composite yarns with oxidized fiber

This study employed a SKF draft system equipped with an additional spreading device to form a high performance flame-retardant composite yarn. For mixing the spread Technora® filaments and Stretch-Broken oxidized fibers, nip of the front rollers was arranged for best dispersion. The yarn unevenness (CV %), strength, abrasion-resistance, and Limited Oxygen Index (LOI) of the composite yarn were evaluated. The cross-sections of the actual composite yarn were observed to assess its structure and the effect on yarn performance. The experimental results showed that the yarn CV% is worse as the yarn count (Tex) tend to be finer. This would be an optimum condition adopting 30 TM for the yarn evenness and yarn strength. After abrasion test, the residual strength of composite yarns remains above 80 %. The LOI value depends on the coverage degree of oxidized fiber outside the yarn surface, and there tended to be a lower LOI value with finer yarn count (Tex). Overall, the T/O composite yarn with uniform distribution structure can provide high performance and flame-retardancy.     

The interaction of moving yarns with stationary surfaces

Ever since the spinning process was developed, numerous research studies have been conducted and many precision instruments have been developed to control the tension in moving yarn. These efforts, however, have remained insufficient because many factors that need to be considered have not been handled in an integrated manner. To overcome this limitation, various parameters that affect the tension must be examined and the relationships among them must be discovered. Hence, the present paper reviews a variety of parameters for yarn moving from a ring spinning machine to a winding machine. These two machines, in particular, involve a series of phenomena in which the yarn passes over a stationary surface. In addition, the relevant parameters related to force, tension, and yarn motion need to be separately investigated in each spinning section (e.g., the balloon, the section from the bobbin to the traveler, and the section from the bobbin to the unwinding package) and at each part (e.g., the traveler, yarn guide, package, and tensioner).     

Investigation on the physical and structural properties of melt-spun multifilament yarns,drawn yarns and textured yarns produced from blend of PP and oxidized PP

In the present study, effect of OPP (oxidized PP) fraction on the mechanical and structural properties of produced fibers is investigated. Polypropylene powder without antioxidant materials was oxidized at the suitable thermal condition. The various fractions of OPP were blended with PP in the chips shape, and employed as starting material in a melt spinning machine for production of filament yarn. Then as-spun filaments were drawn and finally textured. Structural properties including density, birefringence and FTIR and physical properties consisting of shrinkage, tensile properties and crimp properties were measured. Results show that blending of OPP with virgin PP reduces tacticity and crystallinity, but it hasn’t any effect on orientation. Physical properties of drawn yarns and textured yarns were reduced with increasing of OPP fraction. Moreover, increasing of OPP fraction in blend, reduce crimp properties of textured yarn.     

Investigating the effect of various blend ratios of prepared masterbatch containing Ag/TiO2 nanocomposite on the properties of bioactive continuous filament yarns

In this research, possibility of producing and processing antibacterial organic/inorganic nanocomposite polypropylene filament yarns for permanent antimicrobial efficiency has been investigated. First PP powder and inorganic nanocomposite filler were mixed in a twin screw extruder and modified masterbatch was produced. Continuous filament yarn was made by a pilot plant melt spinning machine from the blend of PP granule and various blending contents of the prepared masterbatch. Pure PP and all other combined samples showed acceptable spinnability at the spinning temperature of 240 °C and take-up speed of 2000 m/min. After producing as-spun filament yarns, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Moreover, the DSC, SEM, FTIR techniques have been used for characterization of samples. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified drawn yarns has reached to 5 %. The observed improvement in the tensile properties of modified as-spun yarns compared to the pure PP was significant. Drawing process improved generally the tensile properties of as-spun yarns. Tensile properties of modified textured and drawn yarns were higher than the pure PP. An optimum of antibacterial activity has been observed in the sample containing 0.75 wt% of nano-filler. It is interesting that the optimum of tensile properties has been also obtained for the sample with maximum bioactivity.     

Effects of twisting parameters on characteristics of rotor-spun composite yarns with spandex

Spandex fibers have superior stretch and elastic recovery ability. Composite yarns containing spandex are frequently used to manufacture elastic textile products and accessories. We have developed a composite yarn spinning system that produces different kinds of composite yarns containing spandex on a modified open-end rotor spinning frame. By changing the twisting parameter of composite yarns, we studied the structure and properties of rotor-spun composite yarns with spandex. The results indicate that the twisting parameter has great influence on the structure and properties of rotor-spun composite yarns with spandex. The linear density of spandex filament has influence on the properties of composite yarns too. In comparison with normal rotor-spun yarn, the appearance of composite yarns is clearer, the structure is much tighter, and the properties are improved.     

Study on thermal treatment of hybrid technical yarns

The present paper reports the impact of thermal treatment on the characteristics of core-sheath type hybrid technical yarns. The core-sheath type hybrid yarns are prepared using DREF-III technology. Polyester and glass multifilaments are used as core components whereas the cotton and polyester staple fibers are the sheath components wrapped around the core filament with different proportions to form a hybrid structure. The thermal treatment is carried out both in dry and in wet state under relaxed condition and the thermal shrinkage, sheath-slipping resistance and tensile and bending properties of hybrid yarns have been studied. Thermal treatment markedly increases the thermal shrinkage and sheath-slipping resistance of hybrid yarns with polyester multifilament in core, but insignificant effect for yarns with glass multifilament in core. Breaking elongation of hybrid yarns with polyester multifilament in core increases with treatment temperature. The hybrid yarns with glass multifilament in core are least affected by thermal treatment.     

Weavability limit of yarns with thickness variation in shuttleless weaving

Theoretical weavability limit relationships of fabrics from regular warp yarns and fancy filling yarns with thickness variation in shuttleless weaving are reviewed. The relationships correlate maximum warp and filling cover factors, warp and filling yarn characteristics, the distribution of thick and thin places of filling yarn over the fabric surface, and the warp and filling weave factor. The research considers single filling feeder and multiple feeders cases. Additionally, comparisons between the weavability limit of regular yarns and fancy yarns in shuttle and shuttleless weaving are given.     

Study on characteristics of compact yarns under dynamic state

The dynamic testing conditions simulate actual manufacturing conditions more closely than static testing. In most cases, as results from dynamic tests differ significantly from static tests, dynamic tests are more relevant from the point of view of processing of yarn. The yarns are in motion when they are running on different machines during the production process viz. weaving; knitting etc. Compact ring spun yarns have created a fundamental change how the industry views the ring spinning. The new technology compact yarns such as EliTe® yarns need to be compared with the normal doubled yarns in a dynamic way. This study involves dynamic testing of the EliTe® compact yarns and normal ring spun doubled yarns using CTT (Constant Tension Transport) machine, a versatile test instrument to measure the yarn properties such as dynamic breaking strength, elongation, abrasion, lint, yarn faults (thick, thin places, neps), hairiness etc. EliTe® compact yarns showed higher breaking strength, more elongation, with lesser yarn faults and hairiness, less abrasiveness and less lint generating tendencies during the dynamic testing as compared to the normal ring spun doubled yarns.     

Investigation of inter fiber cohesion in yarns. I. Influence of certain spinning parameters on the cohesion in cotton yarns

This paper investigates the influence of raw material and process parameters in spinning that affect the inter fiber cohesion in yarns. An instrument has been developed for measuring the minimum twist of cohesion. With regard to the raw material parameters, the influence of different cotton fiber mixings for a given count of yarn is investigated. Also the effect of spinning to varying counts for a given cotton variety is studied. With regard to the process parameters, studies have been carried out to investigate the influence of noil extraction in comber, number of draw frame passages, draft pressure in ring frame and direction of twist. Cohesion improved with increase in the noil extraction percentage in the comber. Increase in the number of draw frame passages also improved the cohesion. Draft pressure in ring frame improved the fiber cohesion in yarn up to a pressure of 2.1 kg/cm². Direction of twist had no effect on the cohesion.     

Study on the wicking property of polyester filament yarns

In this paper, the capillary rise method was applied to evaluate the wicking property of polyester filament yarns. Effects of twist, monofil cross sectional shape and texturing on the wicking height were discussed in details. The results indicated that with the increase of twist level, the wicking height ascends until reaching the maximum height, and then descends. It is also observed that under the same twist level, the wicking height of the five-leaf low-stretch yarn is the largest among all those three kinds of yarns, and then is that of the conventional low-stretch yarn. The wicking height of the parallel-drawn yarn is the smallest.     

Automatic detection of the layout of color yarns with logical analysis

In this paper, a novel method based on logical analysis is proposed to recognize the layout of color yarns of yarndyed fabric from the color pattern. The mathematic expressions of the color pattern and the layout of color yarns are introduced first, and then the fitness of the layout of color yarns to the color pattern is defined by the relation between them. The principle of the proposed recognition method begins with the assumption of the color of the first warp yarn in the color pattern. The whole algorithm procedure is then analyzed in detail with an actual sample color pattern. Experiments on some color patterns recognized from actual yarn-dyed fabrics, some color patterns simulated manually and some color patterns including error color information of floats prove that the method proposed in this paper is effective for detecting the layout of color yarns from the color pattern of yarn-dyed fabric and it has fault-tolerance ability in some degree. The research in the paper can be used to construct the whole recognition system of the parameters of yarn-dyed fabric.     

Correlation with itchy feeling of fabric handling change by physicochemical processing of woolen fabric

The purpose of this research is in solution of two important subjects mutually related; (1) creation of fabrics of various handlings by finish processing and (2) mechanism of generation of itchy feeling acting as the hindrance of a comfortable clothing life and establishment of its objective evaluation method. For the purpose of solution of these two subjects, the same fabrics were used and they were changed by 18 kinds of different physicochemical procedures, which come out 18 levels of fabric handlings ranging from very soft to very stiff. As for handlings of 18 kinds of fabrics, the items of Hand Value were calculated based on all of KES basic properties in terms of KES procedures. Solution of these subjects is also connected with a high level of fabric finishing technology. On the other hand, one of the authors is an expert in fabric finish processing, and has been sure of itchy feeling of fabrics being closely connected with the hardness of fabrics from many years of experience. The degrees of itchy feeling for 18 kinds of fabric were judged by 50 evaluators of different ages and occupations, in terms of five ranks of evaluation method beforehand. As a result, itchy feeling had a high correlation with shear properties and Koshi, and had a negative high correlation with Numeri. It was confirmed that that itchy feeling could be evaluated by objective data of KES properties in terms of KES procedure.     

Study on splicing performance of different types of staple yarns

The present paper reports the detailed study on the splicing behavior of viscose staple fiber yarns made from ring, rotor, friction and air-jet spinning technologies. The linear density of all the yearns was kept constant at 29.5 tex. The splicing parameters like splicing pressure and duration of the splicing were taken as variables. Three levels of splicing pressure at constant splicing duration and three levels of splicing durations at constant splicing pressure were considered. Splices were introduced at all these levels for the four different technologies. These splices were tested for their tensile properties and the properties of splices were evaluated in terms of retained splice strength (RSS) and splice break ratio (SBR). The splice photographs were taken and splices were analyzed for their structure and for diameter profile along the length of the splice.     

Muscle activity monitoring with fabric stretch sensors

In this paper, development of a fabric stretch sensor embedded system has been proposed for muscle activity monitoring. It is expected that this product will be proper for monitoring a wide range of human activities mainly due to the characteristics of light-weight and high sensitivity. The fabric sensors developed can be easily attached to almost any types of clothing due to their thin and stretchable natures. The mechanism and performance of the sensors have been characterized by measuring the mechanical and electrical performance along with stretch ratio or strain percent. The data collected would be successfully transmitted to mobile phones through low power consumption BLE connection, and thus muscle activities in real time. As expected, the resultant smart muscle pants could achieve realistic goals through monitoring body movements without any significant loss of wear comforts in normal clothing. This work significantly contributed in enhancing the utility of strain/stretch sensors for development of e-textiles and intended to be a starting point for data collection and analysis of smart fabric embedded sensing technologies.