Weaving Conditions Research Articles

Application of 3D-Woven Fabrics for Packaging Materials for Terminally Sterilized Medical Devices.

This research aimed to test a newly developed 3D fabric for use in a hospital sterilization unit as a packaging material. Two basic properties were tested: the efficiency of the microbial barrier, and the bursting strength of the woven fabric, determined with a steel ball. Material deformations caused by bursting are common in medical sterilization, as a consequence of the packaging of the medical tools needed in surgery. Six 3D-fabric samples were woven from the same warp, with three weft densities and in two different weaves. The weaving conditions and other construction characteristics of the fabrics were the same. To determine the effectiveness of the microbial barrier, bacterial endospores of an apathogenic species of the genus Bacillus, Geobacillus stearothermophilus and Bacillus atrophaeus, were used. Mechanical testing of the 3D-woven fabric, i.e., the bursting strength of the fabric using a steel ball, was carried out according to the standard method. The results showed the exceptional puncture strength of the woven fabrics and their formation of an effective microbial barrier, i.e., complete impermeability to microorganisms in five samples, which is the main condition for possible use as a packaging material in medical sterilization. Sample 3tp did not provide an effective microbial barrier and did not meet the basic requirements for use in medical sterilization.

Study of predicting the number of warp thread breaks during the weaving process

The properties of cotton yarn which will be used as the warp were investigated before the weaving process. The results of the breaking forces served to make an empirical and approximated diagram of the normal distribution. Yarn tests were performed by yarn passing through a weaving process simulator with electronic force measurement, speed, and the number of wefts. The number of breaks was registered during the yarn test. Measurements were performed simulating different conditions of the weaving process (change in reed density, higher dynamic tensile forces, lower dynamic tensile forces, and shed height changes). Data computer processing gave approximate diagrams of dynamic forces normal distribution under the test conditions, which do not show significance according to the χ2-test. By pairing a diagram of the breaking force and a diagram of one of the conditions in the weaving process, shown in the same line of forces, their intersection or surfaces overlap is expressed. Based on the integration of the intersection area of the breaking forces approximated diagrams and dynamic forces in the weaving process, the value of the intersection area according to the test conditions was obtained. A high degree of correlation was found by correlating the actual number of thread breaks registered at the time of testing and the intersection of areas for the corresponding condition. This makes it possible to predict the number of breaks in the warp threads during the weaving process if the yarn characteristics and the weaving conditions are known.

Optimal analysis and application of the warp tension control system for a rapier loom

Traditional proportional–integral–derivative (PID) control performance optimization is an essential method to improve a loom’s warp tension control performance. This work proposes an improved genetic algorithm optimized PID control scheme to overcome the decline in control performance of the traditional PID control algorithm in a loom’s warp tension control system. Through the decoupling analysis of loom motion mechanism, the establishment of warp tension model and the optimization of fitness evaluation mechanism of genetic algorithm can effectively overcome the problems of local optimal solution and algorithm degradation of genetic algorithm. Simulation experiments were carried out with the traditional PID, the integral separation PID, and the genetic PID in warp tension control. The results show the advantage of the genetic-PID algorithm to control warp tension stability. Ultimately, according to the functional characteristics of the loom mechanism, a tension control platform for experimental studies was established. The test results show that the maximum fluctuation range of warp tension is within [−2, +6] at the test speed of 850 rpm, which meets the requirements of long-term stable and reliable control of warp tension under different weaving conditions.

Effect of process parameters on root pass welding and analysis of microstructure in V-groove pulsed gas metal arc welding for mild steel

This study performed root pass welding with a V-groove using a pulsed gas metal arc welding process for mild steel. Welding process parameters such as weaving, root gap size, and travel speed were major factors in the formation of the back-bead. A high-speed camera and a synchronized data acquisition system captured dynamic molten pool images and welding signals (current and voltage) simultaneously. The back-bead shape differed depending on the root gap opening. Without a root gap, the accumulated molten pool created a cushion effect in the arc center which reduced the momentum of downward flow. In contrast, the back-bead depth could be formed with a root gap opening (1 mm, 2 mm), but the back-bead shapes were different from each other at different travel speeds. The back-bead shapes also varied depending on the weaving conditions. Despite the same amount of heat input, the microstructures also varied depending on the weaving. The microstructures in the heat-affected zone with weaving were mixed with ferrite and pearlite. However, the microstructures in the heat-affected zone without weaving mainly consisted of coarse bainite. Acicular ferrite with some amount of grain boundary ferrite dominated in the weld metal in all cases.

Continuous and rapid production of three-dimensional woven fabric preforms using a new weaving technique

A new manufacturing method has been developed to fabricate three-dimensional (3D) woven fabric preforms. The new method can solve problems such as delamination and fiber buckling in composites, which are known disadvantages of two-dimensional (2D) laminated fabric-reinforced composites. The new 3D weaving equipment allows for continuous and rapid production of 3D woven fabric preforms with various 3D structures. We conducted 3D modeling of the resulting fabric structures to assess the capability of the new method and the machinery involved therein. We manufactured 3D woven carbon fiber-reinforced composites using the 3D fabric preforms and epoxy resin via the resin transfer molding process. The internal architecture of the 3D composites was evaluated using micro-computed tomography and compared to the 3D modeling results; it was confirmed that 3D fabric preforms with the desired structure can be manufactured successfully by adjusting the weaving conditions of our novel weaving machine.

Differentiating 3D textile composites: A novel field of application for Digital Volume Correlation

Digital Volume Correlation is an appealing technique for establishing a novel comparison (differentiating) tool based on full field measurements of structured materials such as 3D woven composites. This approach provides a quantifiable description of the weaving distortions on woven composites. It also offers applications ranging from the quantification of the influence of different weaving conditions, up to nondestructive testing of composite parts. The method is validated on real 3D woven composite samples revealing both “metric differences” (deformations of a textile with respect to reference one) and “topological differences” (such as the occurrence of missing yarns).

Mechanical behavior of 2D and 3D weaved SiC-matrix, carbon-continuous-fibre-reinforced composites: Part 2. Fracture toughness under static loading conditions

Advanced materials such as Continuous Fibre-reinforced, Ceramic-matrix Composites (CFCCs) offer significant enhancements in variety of properties, especially tensile stress to fracture, flexural stress and most importantly, the fracture toughness (especially the propagation fracture resistance), as compared to their bulk monolithic counterparts. However till date, there are hardly any scientific studies reported in the open literature on the effects of fibre weaving conditions on the fracture toughness of carbon-fibre based advanced ceramic composites, where SiC is used as the matrix. The present paper discusses the fracture toughness behavior of these CFCCs in 2D and 3D woven conditions, obtained by static loading conditions using 3-point bend/flexural testing. Fracture behavior and principal fracture modes are also evaluated and analyzed to account for the differences in the fracture toughness properties. The variation in plain strain fracture toughness and elastic plastic fracture toughness is also compared. The study showed that the relative difference in the fracture toughness is more or less controlled by the nature of fracture, which is dictated by the differences in the fibre/matrix interface characteristics and to a greater extent by the weave condition.

Mechanical Behaviour of 2D and 3D Weaved SiC-Matrix, Carbon Continuous-Fibre-Reinforced Composites: Part 1. Flexural Strength Under Static Loading Conditions

Advanced composite materials offer significant improvements in diverse properties, such as tensile stress to fracture, flexural strength and most importantly, the fracture toughness (especially the propagation fracture resistance), as compared to their bulk monolithic counterparts. However, there are hardly any scientific studies reported in the literature on the effects of fibre weaving conditions on the flexural strength properties of carbon-fibre based advanced ceramic composites, where SiC is used as the matrix. The present paper discusses the flexural strength behavior of these CFCCs in 2D and 3D woven conditions, obtained by static loading using 3-point bend/flexural testing. Fracture behavior and fracture modes are also evaluated and analyzed to account for the differences in the flexural properties. The study shows that the relative differences in the flexural strengths are more or less controlled by the nature of fracture, which in turn is dictated by the differences in the fibre/matrix interface characteristics and to a greater extent the weave condition.

Evaluation of the Industrial Processability of High-Strength and High-Modulus Yarns in Weaving, Taking into Account Abrasion Resistance

We evaluate the industrial processability of high-strength and high-modulus multifilament yarns in weaving. The procedure for evaluating the processability of a yarn is based on determining the abrasion resistance of the yarns under conditions simulating loom operation. We determine the basic physical and mechanical properties of different types of multifilament yarns, including their abrasion resistance, which affect the processability of the yarns in weaving, letting us predict the weaving conditions.

Gradient colour deviation in woven textiles to correspond to pictorial images in diversity

ABSTRACTThis study aims to propose optimal weaving conditions for creation of a natural shading effect in woven textiles. By applying the weave structure and pattern theories, the two core parts of weaving are explored and examined towards improving realisation of gradient weave colours. When planning experiments, weave repeat sizes from 12- to 30-thread are created into a shaded weave series and compounded in a multi-weft figuring method. In terms of weave pattern, a colour spectrum image is designed and its split primary colour layers (e.g. cyan, magenta, yellow and black) are employed as a weave pattern. In conjunction with varied weaving conditions, a colour spectrum image is reproduced in 19 different woven forms. In this study, comparative analysis is approached based on the samples resulted from trials and the practical research is explained in detail of weave structure and weave pattern specifications to propose the core principle of establishing gradient colour deviation.

Effect of Construction on Strain distribution in Woven Fabrics under Uniaxial Tensile Deformation

Woven fabrics form an integral part of technical textiles where strength is of prime importance. Amongst various factors found to affect the tensile properties of woven fabrics, change in weave and numbers of yarns is expected to alter initial crimps, ease of crimp interchange and fabric assistance in both the principle directions of testing. Accordingly, a strain analysis of plain and satinette woven fabric samples in raveled strip testing mode were undertaken in this work. The samples were generated under similar weaving conditions while varying only the pick density systematically. An analysis of the strain pattern reveals many interesting observations, the most significant ones being (1) the direct relation between the percentage yarn strength utilization in fabric with the uniformity of strain levels along the two principal directions and (2) a significant difference in the strain distribution of samples tested along warp and weft directions irrespective of the construction.

Influence of Fibre Architecture on Impact Damage Tolerance in 3D Woven Composites

3D woven composites, due to the presence of through-thickness fibre-bridging, have the potential to improve damage tolerance and at the same time to reduce the manufacturing costs. However, ability to withstand damage depends on weave topology as well as geometry of individual tows. There is an extensive literature on damage tolerance of 2D prepreg laminates but limited work is reported on the damage tolerance of 3D weaves. In view of the recent interest in 3D woven composites from aerospace as well as non-aerospace sectors, this paper aims to provide an understanding of the impact damage resistance as well as damage tolerance of 3D woven composites. Four different 3D woven architectures, orthogonal, angle interlocked, layer-to-layer and modified layer-to-layer structures, have been produced under identical weaving conditions. Two additional structures, Unidirectional (UD) cross-ply and 2D plain weave, have been developed for comparison with 3D weaves. All the four 3D woven laminates have similar order of magnitude of damage area and damage width, but significantly lower than UD and 2D woven laminates. Damage Resistance, calculated as impact energy per unit damage area, has been shown to be significantly higher for 3D woven laminates. Rate of change of CAI strength with impact energy appears to be similar for all four 3D woven laminates as well as UD laminate; 2D woven laminate has higher rate of degradation with respect to impact energy. Undamaged compression strength has been shown to be a function of average tow waviness angle. Additionally, 3D weaves exhibit a critical damage size; below this size there is no appreciable reduction in compression strength. 3D woven laminates have also exhibited a degree of plasticity during compression whereas UD laminates fail instantly. The experimental work reported in this paper forms a foundation for systematic development of computational models for 3D woven architectures for damage tolerance.

An investigation into the weft insertion periodic errors in fabric using an image analysis method

One of the effective parameters on the balanced weaving conditions with uniform weft density is the rate of fabric take-up that should be equal to pick-spacing in each cycle. The purpose of this research was to investigate the effect of periodic errors of take-up system on the rate at which the faults occurred in the fabric. While correcting a fault during weaving operation in fabric, some new errors were made periodically using a stepper motor and variations of pick-spacing were measured. When faults were created in the take-up system, generated weft strips in fabric were extracted by the image analysis method. The results show that the periodic faults in the fabric are stopped at a specified level depending on the alternation of the error.

Comparative analysis of desizability and retrogradation behavior of various sizing materials

AbstractThe advent of high‐speed shuttleless looms has increased the importance of sizing. Starch has been the most popular and economic size material. Synthetic binders are also being blended with starch to improve weaving loom efficiency. Some synthetic size materials have restrictions in use mainly because of ecological reasons. In the recent years, many modifications have come up in the starch as a sizing agent. Different modifications can give different properties, which can suit to particular application. In this study, different varieties of natural starch, modified starch, and synthetic size materials are evaluated, and properties like retrogradation and desizability were studied to investigate their potential for modern weaving conditions. Comparison is made between various materials and it is observed that paste characteristics and film properties of certain modified starches are better than the natural starch. The experiment was also designed to check the properties of blend constitution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Application of XRF and AMS Techniques to Textiles in the Mongol Empire

AbstractX-ray fluorescence (XRF) and Accelerator Mass Spectrometry (AMS) techniques were applied to four pieces of ancient Mongolian textiles in order to assist cultural studies of the most significant era of medieval western Asian culture. Radiocarbon dating using Accelerator Mass Spectrometry (AMS) was performed in order to determine the historical age of these pieces. Then, X-ray fluorescence analysis using Synchrotron Radiation (SR-XRF) was carried out in order to obtain elemental maps as well as investigate their constituent elements. Results showed that the textiles were produced between13th and 14th century, and possessed elements such as Au, Cu, Fe and Ti were traced in these pieces whereas Au was used to make gold threads. Cu, Fe and Ti are well known as metallic mordant. In addition, high resolution images were obtained using Scanning Electron Microscope (SEM) to observe the textile structure and their weaving conditions. The whole collected data can assist in bringing into light and facilitate a deeper understanding of the medieval Mongolian cultures, the textile technology, staining techniques, material process technology of the Mongolian Empire and their relations with the neighboring east and central Asian cultures, such as Persia, India and China.

Characteristics of Cloth Formation in Weaving and Their Influence on Fabric Parameters

This paper discusses the characteristics of cloth formation in weaving as regards continuous weaving, the concept of balanced weaving is put forward, and an equation of balanced weaving is then established for analyzing the response of the weaving process to disturbances of various kinds. Based on the analysis of beat-up resistance and weft yarn bouncing back, the cloth formation area is defined as an indicator of the weaving conditions. These discussions lead to control of fabric parameters.

A Study of Heat Input Distribution on the Surface during Torch Weaving in Gas Metal Arc Welding

In weaving welding where a V groove exists, the heat input distribution is an important factor that determines the defectiveness of the bead shape, undercut and over-lap. In this study, the amount of heat input, which is determined by the welding current, voltage, speed and weaving conditions is calculated through mathematical development and numerical methods. Furthermore, the heat input distribution as a two-dimensional heat source was observed when applied to each groove. Therefore, a heat input control algorithm is suggested to prevent the defects generated from undercut or over-lap, which was verified through an analysis of the heat input distribution.

Influence of Warp Loading on Weaving Machines upon Yarn Deformation

The breaking force of warp yarns taken per segments on the loom is measured using three weaves from the same warp on different looms. To simulate the deformation of warp yarns, samples from the warp beam are taken and, after various conditions of cyclic stress on a dynamometer, the most approximate degree of warp deformation is that which occurs in the weaving process per segments on the loom and per weave types. The F-test, t-test, χ2-test, and correlation coefficient reveal that there are no differences among breaking force values of the yarns from the looms or on yarns after cyclic stress and relaxation measured on the dynamometer, meaning that deformation imparted to the warp on the loom during weaving is very similar. Deformation caused by friction among yarns and imparted by metal pieces is not discussed here, but is included in the deformation caused by stress. Under the same conditions of cyclic stress, the elongation of the warp during stress in the segments of the loom is tested, and the conclusion is reached that elongation follows yarn deformation almost linearly. Investigations involve the same weaving conditions on the same loom and with the same warp, employing the three weaves. Dynamic tension of the warp is measured for each weave in the course of weaving, and the change in tension caused by changing the weave is registered.

A Study of Start-up Marks of Woven Fabrics

Start-up marks are very disturbing fabric faults, especially relevant to modern high performance looms, which occur when a loom is restarted after stoppages. As weaving machine stoppages are unavoidable, start-up marks remain to be a major quality problem in woven fabrics. This paper deals with an experimental investigation carried out to study the effect of different weaving parameters on start-up marks. Experiments were carried out to investigate the effect of factors such as machine stoppage time, weft sett, warp yam tension, weave pattern, weft material and machine stop position on start-up marks. Variation of pick spacing at the stop position was taken as a measure of the severity of start-up marks. The variation in pick spacing in the start-up marks originating under different weaving conditions were graphically illustrated. The results are discussed to explain how different weaving conditions and settings affect variation in pick spacing and thus cause start-up marks of different severity. The effect of relaxation of warp and fabric on pick space variation in start-up marks is also discussed. The findings of this work are compared with the results obtained by other researchers.

53—THE APPLICATION OF RADIO-TELEMETRY TO THE MEASUREMENT OF WEFT TENSION DURING THE WEAVING CYCLE

A set of criteria is presented for the continuous monitoring of weft tension under dynamic weaving conditions on a conventional shuttle loom. A radio-telemetry system is developed that is designed for the direct measurement of weft tension within the shuttle itself. Components of the system that are described include the transducer, transmitter and amplifier, power supply, switchgear, and aerial; the assembly of these components within the shuttle and the relay of weft-tension traces to an external receiver and recording device are also discussed. The performance characteristics of the monitoring system are studied, and a typical trace of weft tension is related to the action of the various weaving mechanisms on a conventional loom.