Knitted Structures Research Articles

Ukrainian Folk Ornaments in Modern Knitting

National arts and crafts are not only the skills of an individual nation but an ethnic phenomenon that has unique features and serves as a source of information on national history and culture. Decorative and applied art in Ukraine combines the traditions and techniques of manufacturing and decoration, which have been developed and passed down from generation to generation. It has a clear national identity and numerous regional differences in ornamental motifs, compositions and favourite colours. Therefore, the Ukrainian folk art has a significant potential and is a source of ideas in creating modern clothing as well as interior items. Embroidery as a way of creating ornamental motifs on a textile material using various techniques is a common process for decorating clothes and interiors for the Ukrainians. Today, ornamental compositions of embroidered folk textiles could be transmitted into modern clothes using various technologies. However, the use of a knitting machine allows creating a pattern during the item production. The ornament transformation into a pattern for knitting can be carried out with graphic software by creating a grid with a cell size similar to the loop size of a knitted structure for corresponding interlooping. A number of clothing and interior items with ethnic motifs was created using the capabilities of flat knitting machines within the masters programme “Knitting Technology and Design” at the Textile Technology and Design Department of the Kyiv National University of Technologies and Design.

Optimum Constructional Factors of Dust Knitted Filter Fabrics.(Dept.T)

In this research an attempt has been made to modify the construction of a number of circular knitted structures i.e. single jersey, interlock, pile fabrics and single pique - This modification could be achieved by means of knowing the optimum constructional factors of each knitted structure such as type of fibres, tightness factor and yarn twist multiplier. This research is concerned with the evaluation of the selected knitted structures for mechanical and dust filtration applications with regard to specific work of rupure, bursting pressure, rate of abrasion, lateral expansion, filtration efficiency, p ressure drop, air resistance and eqivalent pore diameter. Mathematical models describing these properties could be obtained, by using factorial design method, for predicting the knitted filter performance. By using the mathematical methods, it was found that the optimum fabric construction is recommended to be interlock contained 100% crimped polyester fibres yarn, 16.98 tightness factor (i.e. yam count 20 Ne, loop length 0.31 cm, courses per inch 43.5 and 3.25 &e twist multiplier).

Characterization the Properties of Blended Single Jersey Fabrics using Different Microfiber Yarn Cross-sections and Gauges Machine

Since the last few decades, a development of new types of fibers were appeared in order to improve the mechanical properties of fabrics besides its comfort properties, Cotton material was used as a blended material to enhance the properties of the manufactured products. The main purpose of this article is to investigate the influence of different polyester yarn cross-section and gauges on the mechanical properties of blended knitted samples. In this study two groups of knitted samples were manufactured, using gauge 24 and gauge 20, the samples were implemented with single jersey knitted structure by two different polyester microfiber cross-sections and blended cotton ratio. Some of mechanical properties were carried out for all samples such as air permeability, spray test, bursting strength and roughness. The result values recorded and tabulated, as well as statistically analysis using ANOVA Two-way Measurements were executed. The results illustrate that tests properties of blended knitted samples were significantly affected by variables except the spray test. In the same context the results clarify that trilobal cross-section improves UPF property for knitted samples. Finally, due to study the performance of each sample the radar chart was occurred, as the results revealed that Polyester Trilobal samples recorded the best sample radar area with different gauges.

High sensitivity and flexible fabric strain sensor based on electrochemical graphene

In this study, electrochemical graphene (ECG) was chosen to be attached to a polyester fabric with a knitted structure as a flexible fabric strain sensor through a cloth dyeing method. According to scanning electron microscopy observation and Raman scattering spectroscopy measurements, ECG was successfully attached to the fabric structure. The electromechanical performance and strain sensing properties of the graphene-based flexible strain sensor were evaluated. The resistance change and gauge factor of different ECG attached as a fabric strain sensor were quantified. The gauge factor of the fabric strain sensor with less ECG is greater than that of the fabric strain sensor with more ECG. The high gauge factor of 47 was achieved in a strain range from 0% to 2%. The fabricated strain sensor exhibited high sensitivity, fast response time and good repeatability. The fabricated ECG fabric strain sensor could be used to detect tiny physiological signals and human motion.

Process development and compression behavior of innovative 3D bi-directional flat-knitted spacer-reinforced composites

3D knitted fabrics are regarded as a viable option for advanced composite materials. Flat-knitted spacer fabrics (FKSF) which are in the category of 3D knitted structures have attracted many attentions due to outstanding characterizations such as high formability and good impact behavior. These structures consist of two surface layers which are linked together by multiple knitted connecting layers. Despite the merits of 3D-FKSFs as composite reinforcements, they have some structural restrictions such as limited thickness. This study aims to develop and characterize bi-directional 3D knitted spacer structures which could be replaced with conventional FKSFs. In the developed structures, the upper and lower surface layers are connected together by two truncated pyramids which can be configurated in any dimensions using an innovative knitting technique. For providing a report regarding their compression behavior, these 3D structures were produced in two different thicknesses on an electronic flat knitting machine. Then, they were impregnated with epoxy resin via vacuum resin transfer molding and the cured composites were subjected to compression force. The results revealed that their compression behavior is similar to the behavior of conventional honey-comb sandwich structures.

Knit Architecture for Water-Actuating Woolen Knitwear and Its Personalized Thermal Management.

Personalized thermal management using water-actuated woolen knitwear has great potential for smart textile production. However, woolen knitwear exists in a wide range of forms with different derivatives. Manufacturing of smart woolen structures with excellent cooling properties is linked to certain parameters such as changes in loop formation, loop shape, and yarn arrangement upon stimulation of body fluids. To address this issue, textile knit structures with different physical and mechanical properties have been prepared using water-responsive descaled wool fibers and their smart heat and moisture regulation behavior have been investigated and compared to detect the fabric architectural effect on water actuation and cooling performance of woolen garments. The evidence suggests that the technical structure of the fabrics plays a crucial role in pore actuation and fabric cooling performance. The water actuation and thermal management abilities of single jersey were greatly enhanced because of unbalanced structures with lower mechanical stress among the loops and yarns. The experimental data is also in line with the theoretical analysis. Hence, the unbalanced structures control fast heat and mass transfer from the human body, which may offer a promising year-round clothing material to the wearer. This material can have a similar response upon contact with body sweat and humid environments and hence can act as a skinlike fabric. Their possible applications can lie in different fields, such as thermoregulation, functional clothing, sportswear, and medical care.

Design of warp knitting electronic shogging system based on mixed-velocity planning curve

To realize high-speed running of a warp knitting machine, the shogging motion should not only meet the requirement of high dynamic response but should also satisfy high positioning accuracy. Due to the large location disturbance and the dynamic response delay in the interpolation method or the single velocity planning curve method, an electronic shogging system for a warp knitting machine based on the mixed-velocity planning curve is proposed in the present study. Through the analysis of the shogging motion combined with the knitted structure, the optimal resolution of the instruction signal is calculated, which is 725 pulses for one needle step, and the velocity loop bandwidth of the servo driver is optimized. In addition, the motor with a load inertia ratio close to 1 is also selected. Analysis of the shogging motion vibration curve confirms that the shogging motion has advantages of high positioning accuracy and high dynamic response under the mixed-velocity planning curve. The response performance with the mixed curve is 12.5% higher than that with the quintic polynomial, and the positioning accuracy of the mixed curve is 26% higher than that with uniform acceleration–deceleration curve.

Textile testing to assess the resistance to damage of long-lasting insecticidal nets for malaria control and prevention

BackgroundLLINs are susceptible to forming holes within a short time in use, compromising their ability to provide long-term physical protection against insect-borne vectors of disease. Mechanical damage is known to be responsible for the majority of holes, with most being the result of snagging, tearing, hole enlargement, abrasion and seam failure, which can readily occur during normal household use. To enable an assessment of the ability of LLINs to resist such damage prior to distribution, a new suite of testing methods was developed to reflect the main damage mechanisms encountered during normal use of LLINs.MethodsFour existing BS EN and ISO standards used by the textile industry were adapted to determine the ability of LLINs to resist the most common mechanisms of real-world damage experienced in the field. The new suite comprised tests for snag strength (BS 15,598:2008), bursting strength (ISO 13938-2:1999), hole enlargement resistance (BS 3423–38:1998), abrasion resistance (ISO 12947-1:1998) and new guidance around the seam construction of LLINs. Fourteen different LLINs were tested using the new suite of tests to evaluate their resistance to damage.ResultsThe resistance to mechanical damage of LLINs is not the same, even when the bursting strength values are comparable. Differences in performance between LLINs are directly related to the fabric design specifications, including the knitted structure and constituent yarns. The differences in performance do not primarily relate to what polymer type the LLIN is made from. LLINs made with a Marquisette knitted structure produced the highest snag strength and lowest hole enlargement values. By contrast, LLINs made with a traverse knitted structure exhibited low snag strength values when compared at the same mesh count.ConclusionsPrequalification of LLINs should consider not only insecticidal performance, but also inherent resistance to mechanical damage. This is critical to ensuring LLINs are fit for purpose prior to distribution, and are capable of remaining in good physical condition for longer. The new suite of test methods enables the performance of LLINs to be assessed and specified in advance of distribution and can be used to establish minimum performance standards. Implementation of these testing methods is therefore recommended.

Design of Electro-Thermal Glove with Sensor Function for Raynaud's Phenomenon Patients.

Raynaud’s phenomenon (RP) is a disease that mainly affects human fingertips during cold weather. It is difficult to treat this disease using medicine, apart from keeping the body in a warm environment. In this research, conductive knitted fabrics were fabricated to help relax the vessels of the patient’s fingertips by providing proper heat, and also serving as a sensor to detect finger motion after relaxation of the blood vessels of patients. Four different structures, termed plain, purl, interlock, and rib were produced using conductive silver/PE (polyethylene) yarn and wool yarn, with a computerized flat knitting machine. The effect of knitted structure on the electro-thermal behavior, sensitivity, and stability of resistance change (∆R/R) under different tensile forces was investigated. By comprehensive comparison, the purl structure was identified as the preferred structure for the heating glove for RP patients, owing to superior electro-thermal behavior. Additionally, the purl structure had a greater capacity to detect different motions with stable resistance change. This potential electro-thermal glove could be used for functional, as well as aesthetic (fashion) purposes, and could be worn at any time and occasion with complete comfort.

Influence of inlaid material, yarn and knitted structure on the net buoyant force and mechanical properties of inlaid knitted fabric for buoyant swimwear

Buoyant swimwear is becoming more common in recreational swimming use, so the performance of buoyant fabric is important when designing functional swimwear. In this study, potential buoyant inlaid knitted fabrics for buoyant swimwear are investigated. Three types of knitted structures, half milano, full milano and 1 × 1 rib, are selected and various kinds of tubes and foam rods in different diameters are prepared for inlaying during the knitting process by using a 7 G hand-knitting machine. The mean differences among the levels of three independent variables, (1) inlaid material, (2) yarn and (3) knitted structure, on three dependent variables (net buoyant force, compression and tensile properties) are analyzed by using a multivariate analysis of variance. The result shows that the net buoyant force and mechanical properties of the fabric are significantly different due to the inlaid material and knitted structure, but not the yarn. The net buoyant force increases with fabric thickness and the outer diameter of the inlaid material. The inlaid fabrics are less compressible than the control fabric and show better recoverability with an increase in the diameter of the inlaid material. For the tensile properties, the inlaid material reinforces the fabric in both the wale and course directions, in which the stiffness in the course direction is significantly increased. The inlaid fabric is stronger and resistant to breakage in the course direction when the diameter of the inlaid material is increased. The findings of this study contribute to developments in the textile and sportswear industry.

Ag Coated Pa-Based Electro-Conductive Knitted Fabrics for Heat Generation in Compression Supports

Abstract This work deals with the electrically conductive textiles for heat generation in orthopedic compression supports. This study aimed to develop compression knitted structures with integrated electro-conductive yarns and investigate their heat generation characteristics and temperature changes during the time and under stretch which is required to generate compression. Combined half-Milano rib structured knitted fabrics were made by using silver (Ag) coated PA yarn of linear density of 66 tex and 235 tex, respectively. Six variants of specimens were developed by using different amount of electro-conductive yarns in a pattern repeat. It was found that stretch negatively influences temperature values as well as time in which the required temperature is reached. Therefore, the final wearing conditions have to be summed up during the designing of compression orthopedic heated supports.

Failure analysis of 3-D woven and 3-D knitted structures

Attributable to complex structural characteristics, the 3-D hierarchical structures possess different failure modes as compared to the traditional laminate structures, resulting in improved impact resistance properties. In this work, a comprehensive study of ballistic performance of 3-D woven and 3-D knitted structures has been undertaken and suitability of these structures for various applications on the basis of their geometrical distinctiveness has also been described. Different material systems have been investigated which are considered to be suitable for ballistic applications. Ballistic testing has been performed on leading 3-D hierarchical structures woven/knitted by polyamides (aramid, PA-6) and ultra-high-molecular-weight-polyethylene (UHMWPE) filaments to study their failure mechanisms against 30. Cal FMJ projectiles. The experimentation has been performed utilizing light-gas gun apparatus, under the instructions provided by internationally known standard NIJ-0101.06. Furthermore, appropriate sabot design has been scrutinized which is crucial to the whole experimental procedure, as sabots hold the projectile into the gas gun barrel and plays the key role in keeping the projectile straight and maintaining its velocity. Damage patterns were found to be different in knitted and woven structures; as knitted structures showed smaller damage affected region as compared to woven preforms.

Impact of the Presence of the Loop at Different Location on Fabric Width and Areal Density of a Weft Knitted Structure

Knitted structures are progressively built up from row after row of knitted intermeshed loops known as knitted loops. Apart from this knitted loops, tuck or miss loops may be produced by varying the timing of the intermeshing sequence of the old loop and new loops. These loops are main and prominent part of the design of the weft knitted structures. Structures having float or miss loop exhibits many noticeable characteristics. The fabrics renders better surface appearance or color pattern. Dimensional stability is significantly improved. Fabric width is reduced and areal density is also increased considerably due to the presence of float loops in the structure. Therefore, the dimensional and physical features of different knitted structures having knit-miss loops may be studied carefully to find the influence of float stitch or loop on fabric width and areal density. In this project work, such an attempt has been made to specify some specific single jersey structures, which will be ensured as an effective tool for product research and development as well as for meeting up customer’s quality requirements of high class products.

Designing compression of preventive compression stockings

The paper focuses on leg diseases and the application of preventive compression stockings in people who perform their working tasks in the standing position, pregnant women and recreational athletes. Specific amounts of compression classes from several significant European standards are shown. Structural properties of knitted fabric structure in the production of preventive compression stockings are given. Tubular elastic knitted fabric samples of uniform structure which are used in the production of preventive compression stockings and pantyhose were produced. The yarns used for knitting were PA microfilament yarns in the counts 40 dtex f 40 and 60 dtex f 60 and elastane yarn in the count 22/17 dtex f 7. Tubular elastic knitted fabric samples of the structure intended for preventive compression stockings were made on a single-bed hosiery knitting machine with a gauge of E32 and needle bed diameter of 100 mm (4″) with 400 needles. The samples were made in jersey plated and partially plated structure 1 + 1 at three loop sinking depths. The widths of the tubular knitted fabric samples were 98 to 113 mm. The produced samples were pulled onto rigid cylinders of the circumferences 240 to 790 mm and the compression measured by the Pico Press device was 1 to 24 hPa.

Investigation of thermal comfort properties of electrospun thermoplastic polyurethane fiber coated knitted fabrics for wind‐resistant clothing

AbstractThe integration of nanofibers into conventional fabrics may open up new opportunities such as improving the comfort performance and thermal management properties of outdoor clothing. Nanofibers are able to form a highly porous mesh and their large surface‐to‐volume ratio improves performance for many applications. This study shows the possible utility of the nanofiber coating on conventional knitted fabrics for improving the wind‐resistance and breathability properties. It was seen that nanofiber coating did not cause a significant effect on water vapor and thermal resistance of electrospun thermoplastic polyurethane nanofiber coated cotton (CO), modal (CMD), viscose (CV), and lyocell (CLY) single jersey fabrics, while resistance to air permeability was increased with the increased nanofiber coating. High level of air resistance was achieved with 30 min of coating. In terms of comfort properties, the nanofiber coating proved to be advantageous due to its lower air permeability with its water vapor permeable structure. However, thermal insulation level of these fabrics was still low and fragile nanofiber layer needed to be protected. Therefore, a multi‐layered fabric form was derived from combination of cotton and lyocell fabrics with a nanofiber layer. The results showed that nanofibers could be used to improve the wind‐resistance and comfort properties of multi‐layered knitted structures.

Effect of Stitch Characteristics on Flammability and Thermo-Physiological Comfort Properties of Knitted Fabrics

Investigations on influence of stitch types in single jersey knitted fabric on flammability and comfort properties are carried out in this paper. Seven different knitted structures were developed on single jersey machine. In this study the effect of combinations of knit, miss and tuck stitches on comfort and flammability properties of knitted fabrics are investigated. Flammability test/properties e.g. afterglow time, char length, and weight loss % are evaluated. Several tests for thermophysiological comfort i.e. air permeability, thermal resistance and absorbency are also carried out. Results obtained show that both comfort and flammability properties are dependent on type of stitch, pattern of stitch, location of stitch and percentage of any stitch used in the fabrics. Moreover, fabric physical parameters also affect the flammability and comfort properties. The findings of this study shall work as a guide for material or textile engineers in the design and selection of fabric for apparel as well as high performance thermal protective clothing; as a result safety and occupational health of fire fighters will be improved.

Development, investigation and evaluation of smart multifunctional socks

The use of a new generation chemical fibers with various functional additives offers new possibilities for the development of advanced (multi)functional textile products. Such compounds as phase change materials (PCMs), metals (like cooper, silver), also natural or chemical insect repellents, FIR emitting ceramic particles and etc. incorporated into fibres’ structure are essential for development of knitted fabrics directly contacting to the skin with effective thermoregulation and such protective properties as: antimicrobial, antistatic, repellence against blood sucking insects. The main parts of socks investigated were knitted in plain plated single jersey pattern. The 3-ply twisted yarns of new structures were used in the outer layer of socks. Yarns were made by using single yarns with PCMs, insect repellent permethrin, ceramic and silver additives containing fibres (Cell Solution® Clima, Cell Solution® Protection, Resistex® Silver). The inner layer of socks was made of polyester (PES) 3-ply twisted yarns with different number of filaments resulted in different structures of socks’ fabric. Based on all obtained thermoregulating and protective characteristics of investigated different knitted fabric structures of socks, the optimal knitted socks were selected. The obtained results of investigations are significant for the development of other knitted fabrics worn next to the skin.

Development and Investigation of a Textile Heating Element Ensuring Thermal Physiological Comfort

The aim of this research was to develop a flexible heating element and investigate its heating capability in simulated wearing conditions. Polyester silver (Ag)-plated yarns incorporated in the reverse side of the knitted structure were used to provide electrical conductivity. A special knitted structure was selected to keep conductive yarn only in the reverse side of the material. All the heating element was made using only textile materials and yarns. A temperature sensor thermistor was used as an electronic element to follow the body temperature, and the remaining elements ensuring a correct electric circuit and heating were made of textile. Another type of heating element was produced using enamelled copper wire, which was inserted into the knitted fabric structure. Investigation of both types of heating elements was made by determining the dependences of the heating elements’ temperatures on the current and voltage applied. It was concluded that the heating element with silver plated yarns used gave out warmth more evenly over all the resistive area. The microcontroller, which has a heating dynamics data storage function, was programmed to control the operations of the two heating elements. A model of an intelligent apparel product with two heating elements ensuring a comfortable microclimate for the user was created. Field tests were performed for the model created by wearing the product and setting the temperatures of both heating elements, for which the continuous operating time was determined.

Influence of orthopedic support structure and construction on compression and behavior during stress relaxation

This work was focused on changes of the compression generated by knitted orthopedic supports during the stress relaxation in order to find in which period of the stress relaxation the most significant part of the compression is lost. The influence of knitted structure, elastomeric inlay-yarn insertion density and shape/orientation of the rigid element fixed on the fabric on the compression and its changes under the stress relaxation was also investigated in this study. 11 different knitted structures and constructions were used in this research. It was found that the higher density of elastomeric inlay-yarn insertion into the knitted structure is not only responsible for higher compression generation, but also makes compression degradation during the time slower. In addition, the higher pre-tension of the elastomeric inlay-yarn leads to the faster relaxation process. Moreover, the shape and orientation of the rigid element can significantly affect the compression generation, however behavior of all variants during the stress relaxation is very similar. Evaluation of the tensile force after at least 120-300 s of the stress relaxation has to be used in design algorithm of very different compression products and applied in estimation of the compression at different manufacturing stages of the product.

СТВОРЕННЯ ПАРАМЕТРИЧНОЇ МОДЕЛІ ПОВЕРХНІ ТРИКОТАЖУ ПЕРЕПЛЕТЕННЯ ЛАСТИК 2x2

This study aims to develop an algorithm for constructing surface models (macro-models) of rib knitted structures, for three-dimensional modeling of tensile deformations in coursewise direction and predicting the physical and mechanical characteristics of knitted fabrics and products. During the research, methods of theoretical analysis, spline theory, computer graphics, programming tools have been used. As a result of the research, it was found that for modeling of some physical and mechanical characteristics of knitted rib structures in a deformed state, it is advisable to use geometric models that reproduce the geometry of the knitted fabric surface with high accuracy, but do not have detailed structure at the level of fibers and threads. If necessary, the values of air permeability, thermal conductivity and others porosity for such models can be taken into account under the form of appropriate indexes. At the same time, to calculate the coefficients of porosity and air permeability, one can use both experimental data and 3D models with a higher detailed structure of the textile material (meso-model). In the course of research a set of geometrical characteristics of samples of rib knits patterns is formed. Samples of 2x2 rib knits of PAN yarn of 31х2 tex have been made with a flat bed knitting machine of 10th gauge. The samples were suspended in the clamps of the relaxometer type "rack" and loaded with weights weighing from 20 to 120 g with an interval of 20 g. By means of the camera, the geometrical characteristics of the knitted surface in dry-relaxed state and in 6 discrete tensile states were recorded and determined. According to the obtained data, parametric 3D models of the knitted surface were built. An algorithm for constructing a macromodel of knitted rib 2x2 structure in the process of stretching in the coursewise direction, taking into account the peculiarities of the situational change in the geometry of the thread within the report has been developed. Three-dimensional parametric models of knitted surface (macro-models) of knitted 2x2 rib structures in the Autodesk Inventor environment have been created.