A novel method based on loop shape for simulating knitted fabric using mass spring model

Fabric simulation is result of combining various methods that have been dramatically evolved during the decade. However, there still exist some limitations. One of the limitations in fabric simulation is lack of using fabric properties such as material, weave structure, density and so on in mass spring modeling. In knitted fabrics, this issue is more important due to their different fabric structures. In this paper, a new mesh based on loop shape for simulating 1×1 rib fabric is proposed which is called Loop mesh. By using the Loop and common meshes, 3D model of drape behavior in 18 types of knitted fabric are simulated. Results of simulation are compared with 3D shape of actual drape behavior in fabric samples which are achieved by depth camera. Results show that the Loop mesh is able to predict the drape behavior of knitted fabric with error value of 5 percent as compared with the real result. It can be found that the Loop mesh produced a closest drape shape to the actual fabric drape than other mesh models.     

Fast garment drape simulation using geometrically constrained particle system

A simulation system for versatile garment drape has been developed. Using this system, the shape of a garment can be simulated in consideration of fabric physical properties as well as the interaction between fabrics and other objects. Each fabric piece in a garment is modeled using a geometrically constrained particle system and its behavior is calculated from an implicit numerical integration algorithm in a relatively short time. The system consists of three modules including a preprocessor for the preparation of fabric patterns and external objects, a postprocessor for the results of three-dimensional visualization, and a drape simulation engine. It can be used for the design process of textile goods, garments, furniture, or upholsteries.     

Study of PES sewing thread properties

The properties of 100 % PES core-spun threads were studied before and after the sewing process at different stitching speeds, by determination of the threads tensile force during the sewing process and by changes of the mechanical and thermo-mechanical properties after the sewing process. This analytical method is especially advantageous when monitoring contemporary thermal and mechanical effects, as is the case when loading the sewing thread. Loadings during the sewing process cause structural changes in the thread-twisted fibres. This is confirmed by changes in the thermo-mechanical properties after the sewing process. Simultaneously, changes in the threads mechanical properties after sewing were also observed.     

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.     

Intelligence control of on-line dynamic gray cloth inspecting machine system module design. I. Tension controller design

Tension is very closely related with fabric inspection quality, as not well controlled tension of gray cloth will lead to stretch, relax or fold of gray cloth, so that no sharpest image can be taken. Now that gray cloth tension and convey speed are related with taking sharp image, so this study attempts to design a gray cloth tension control module, develop the intelligent online dynamic gray cloth defect automatic detection system. Gray cloth tension control module makes direct regulation of structural tension of feed and wind rolls and conveys speed control module by load cell coupled with A/D, D/A signal conversion and two sets of inverters. This study utilized fuzzy control theory to design controller so as to keep surface tension consistency of gray cloth, improve recognition rate of gray cloth defect, so that the system can have high action efficiency. In previous fuzzy controller designs, membership functions were often designed by means of trial-and-error method, which usually cost much time. This study used Taguchi method to make membership function programming, and made main effect analysis to choose a group of optimal membership function combination. Through systematized, efficient experimental design, tension controller designed in this study could stabilize gray cloth tension very soon, and acquire sharp gray cloth image.     

Parametric body model generation for garment drape simulation

A parametric body model generation system has been developed. Using various mathematic and geometric algorithms of this system, a three-dimensionally scanned human body can be converted into a resizable body model. Once a parametric body model is formed, its size and shape can be modified instantaneously by providing appropriate anthropometric data. To facilitate the subsequent pattern arrangement process for garment drape simulation, a bounding box generation algorithm has been developed in this study. Also the model can be converted into a set of parametric surfaces that it can also be used for three-dimensional garment pattern design system.     

Drape behaviour of seamed fabrics

Clothe drape depends, on the one hand, on the mechanical and constructional properties of the textile materials and, on the other hand, on the form — construction of the cloth, and their connected positions at the seams. This article analyses the influence of seam types and directions on fabric drape. The drape coefficient together with the number and distribution of folds were determined using a Cusick Drape meter with a video camera and Drape Analyser. The results of our investigation showed that the number of folds on the samples with seams was greater, or in some cases, equal to samples without seams. The distribution and form of the folds also changed. Drape coefficient was, in most cases, greater on samples with seams than samples without seams. Furthermore it was discovered that by measurement repetition the angle values are similar even when the folds on the samples are not distributed in the same manner.     

Determination of fabric physical properties for the simulation of Cusick drapemeter

A fabric drape shape database has been prepared to find the optimum combination of fabric physical properties for simulating the appearance of an actual fabric. First, an objective and quantitative evaluation method for the traditional Cusick drape tester has been devised. Then a virtual drape tester has been developed using an implicit integration based drape simulation engine to generate a series of virtually draped fabric with various physical properties. Finally, a search algorithm has been developed to find the optimum property combination for target fabric by comparing the simulated results with the Cusick drape tester result of that fabric.     

科技创新背景下的夏布产业与制作技术——科技创新在纺织大国向强国转变中的作用

本文以传承至今的中国古老纺织品夏布为视角,通过夏布的传承情况,阐述夏布的理论研究、制作技术现状以及发展情况.进而从夏布产业发展的角度指出了中国从劳动力成本优势为主的纺织大国向科技创新、生产高附加值产品之强国转变的必要性.     

Development of a platform for realistic garment drape simulation

An integrated platform for garment drape simulation system has been developed. In this system, garment patterns from conventional two-dimensional CAD systems can be assembled into a three-dimensional garment on a parametrically resizable realistic human body model. A fast and robust particle-based physical calculation engine has been developed for garment shape generation. Then a series of geometric and graphical techniques were applied to create realistic impressions on simulated garments. This system can be used as the rapid prototyping tool for garments in the future quick-response system.     

Intelligence control of on-line dynamic gray cloth inspecting machine system module design. II. Defects inspecting module design

This study aimed to establish a set of gray cloth defect inspection module using image processing technique, so as to develop a full intelligent online dynamic gray cloth defect automatic inspection system. Gray cloth defects to be recognized in this study included holes, stains, warp missing, spider web and weft missing. First use wavelet transform and co-occurrence matrix to find features of gray cloth defect image, next, use back-propagation neural network (BPNN) to make gray cloth defect classification and data output. BPNN was capable of solving nonlinear problems, thus assisted in enhancing defect recognition effect. As every defect to be inspected in this study varied in size and shape, so advantage of BPNN could be used as aid more than else. This study primarily utilized image processing technique to inspect gray cloth defects, not only in a faster speed than common visual inspection, but also eliminating arbitrary factors of inspectors in body and psychology during inspection, resulting in absolute objectivity. Finally, tension control module built in Part 1 and gray cloth defect inspection module built in this study were integrated, and a full intelligent online dynamic gray cloth defect automatic inspection system established. As validated by experiment result, the system established in this study could successfully recognize gray cloth defects, with total recognition rate amounting to 92.5 %.     

Application of silver nanoparticles to industrial sewing threads: Effects on physico-functional properties & seam efficiency

In this study, the role and impact of silver nanoparticles on industrial sewing threads have been investigated. Study of nanocoating on industrial sewing threads may be useful especially in the areas where skin comes in contact with the garments where anti-bacterial properties may be very useful. Silver particles are considered to have excellent anti bacterial properties. To understand the impact on sewability, investigation was focused to changes at the structural level, changes in physical and surface properties, tensile properties and anti-microbial properties of the nanotreated sewing threads. The structure and morphology of the silver nanoparticles on the sewing threads was observed by scanning electron microscopy (SEM) and quantitatively confirmed by fourier transform infrared spectroscopy (FT-IR). A number of experimental methods and mathematical formulae were used to test individual threads. Custom designed fixtures were used for the study. All the results have been statistically analyzed and found to be significant. The effect of silver nanoparticles on physical properties, functional properties and seam efficiency was illustrated. The difference of the impact of silver nanoparticles on cotton and polyester sewing threads has been compared. It was found that silver nanotreatment leads to a significant reduction of tensile strength. The warp-way seam strength increased where as weft-way seam strength decreased due to damage of yarn. Deformation properties of the threads are not influenced significantly by nanotreatment. The nanotreatment of threads improves its frictional properties significantly. The threads also acquire effective anti-microbial properties with silver nanotreatment. Study of the impact of nanotreatment on the properties of cotton and polyester samples showed a bigger impact on cotton samples than polyester samples. The effect was durable even after several laundering treatments.     

Shadow Moiré aided 3-D reconstruction of fabric drape

The existing standard test method assesses draped fabrics two-dimensionally. In this study, a novel method is introduced to analyze and quantify fabric drapes in 3-D by using shadow moiré method. Six different woven fabrics with dissimilar drape behaviors have been analyzed. A drape index has been mathematically derived from the moiré patterns employing the shadow moiré topography technique. The results have been compared with the standard drape coefficient. The 3-D profile of fabrics has been graphically formed and displayed applying the moiré fringes?? data.     

分宜县苎麻夏布业健康发展

“九五”以来，分宜县瞄准本县传统的苎麻夏布特色，制定了一系列发展苎麻夏布业的优惠政策，通过实施推广苎麻良种、改善麻园生态、农民培训、高产示范、做大龙头企业等措施，使全县苎麻夏布业龙头企业规模不断增大，产品创新创名牌，种麻大户涌现，夏布织造业稳步发展，苎麻产业链不断延伸和升级。     

Study on dynamic needle thread tensions in a single needle lock stitch (SNLS) sewing machine. I. Effect of stitch length,check spring tension,fabric feed timing and needle thread in-take length

This paper, the first of a two-part series, aims to find the effect of stitch length, check spring tension, fabric feed timing and needle thread in-take length on tension peaks occurring on a spun polyester needle thread during a sewing cycle of a SNLS sewing machine. The pre-tensions on the bobbin and needle threads and sewing speed were kept constant. A PC interfaced measuring instrument was fabricated to measure dynamic sewing tension on needle thread above the needle bar. Four prominent tension peaks were detected. Longer stitch length causes higher tension peaks; and shorter length stitch requires higher pre-tension to obtain a balanced stitch. The check spring tension has no effect on tightening tension. Incorrect timing of feed dog can cause very high tightening tension. The change in the position of thread length guide alters the friction of needle thread at critical guides which determines the length of thread to be released through tensioner; release of longer length of thread results in lower tension peaks (1, 2 and 4) and vice versa.     

A new method to determine viscoelastic properties of corn grits during cooking and drying

The working principles and the theoretical background of a new method to measure the viscoelastic properties of grains during cooking and drying processes are presented. Specifically, corn grits at different processing stages of cooking and drying were chosen as the model grain and their viscoelastic characteristics, namely elastic stiffness and viscous damping, were determined. During the measurements grits were squeezed between a rigid bottom plate and a top round element oscillating at random frequencies in a range 10–10,000 rad/s. A frequency response of the mechanical impedance of the samples, which is defined as the ratio between the force applied to the samples and the oscillation velocity, was obtained. Corn grits were measured in their raw state, after cooking in a pressure cooker for different times (2, 7, 15, 30, and 60 min), and at different times of drying (30, 60, and 120 min) at 65 °C. The measured mechanical impedances of the samples showed that rheological changes upon processing can be monitored by the newly developed method. Non-destructive and quick measurements, data covering a wide range of frequencies, and the adaptability of the method to be used with available instruments used in texture measurement such as texture analyzers are some of the important advantages that the new method provides to the area of cereal processing.     

Seam pucker and formability of the worsted fabrics

The purpose of this study is to objectively evaluate the seam pucker as a fabric formability and to analyze the effects of the fabric structural and sewing parameters to the seam pucker properties of the worsted and wool/polyester blend fabrics. The seam pucker of the worsted and wool/polyester blend fabrics according to the different types of fibre composition were surveyed by measuring fabric mechanical property using KES-FB and FAST systems and also seam puckering test was conducted by objective and subjective methods. In addition, the effects of fabric structural and sewing parameters to the seam pucker were investigated using statistical analysis. It was revealed that the effects of fabric structural parameters to the seam pucker were dominant than those of sewing machine conditions. It was shown that low pressor foot pressure and shuttle tension make good seam pucker, and high sewing speed and shuttle tension make bad seam pucker. And it was also shown that the precision on estimating of the seam pucker by KES-FB system was much higher than that of FAST system. And seam pucker values between objective and subjective methods showed good correlation.     

Drape simulation of three-dimensional virtual garment enabling fabric properties

This study analyzes how the silhouette of virtual garments applied to virtual avatars is altered according to various virtual fabric properties. This study measures the properties of real fabrics that include a charmeuse (#F1) and gabardine (#F2) using the Fabric Analysis by Simple Testing system; in addition, the material properties of different real fabrics were applied to that of the virtual fabric. It then evaluates the drape stiffness and silhouette of the virtual garments according to the different fabrics. This study also compared the virtual garment silhouette of sample fabric #F1-S that changed only the stretch property of the sample fabric #F1 with the virtual garment silhouette of sample fabric #F1. The results show that the fabric properties including bend, thickness, weight, stretch, shear values affect the drape stiffness, silhouette, and fit of the virtual garment simulated on virtual avatars and may be used for the realistic virtual garment technology.     

Application of artificial neural network (ANN) for prediction of fabrics’ extensibility

In the field of clothing technology, prediction of the fabric properties is very important because the fabric is the basic element of every clothing item. Knowing the fabric properties it is possible to predict fabrics’ behaviour during process of clothing manufacturing (in phase of cutting, sewing and ironing) as well as clothing items’ behaviour during usage. According to the fabrics’ characteristics and model design it is possible to predict appearances of the clothing items and their draping which can be presented with many computer simulations. In this paper extensibility of the fabric which appears during a small forces loading on the fabrics are investigated. Loading of small forces on the fabric appears in each phases of clothing manufacturing processes and during usage of clothing items. Investigations are managed on 50 fabrics which are weaving in twill weave and 100 % wool. The basic characteristics of fabric (density of warp and weft, mass per unit area, thickness) are defined according appropriate standard methods and tensile properties in the warp and weft directions are measured using KES-FB1 measuring system. Using an artificial neural network (ANN) prediction of extensibility properties of the fabrics are done, results are compared with experimental values and deviations are determined. ANN is an adaptive system that changes its structure based on external or internal information that flows through the network during the learning phase. They can be used to model complex relationships between inputs and outputs or to find patterns in data. Based on the implemented investigations, minimal deviations between experimental and predicted values are obtained and can be concluded that ANN can be used for prediction of the fabrics properties.     

A study on correlation between warp tension and weaving condition

In connection with an effect on development of dynamic model of beat-up process, beat-up force and weaving condition, this study has investigated a correlation of 4 kinds of weaving factors (warp tension, weft thickness, weft density and shedding height) that affect beat-up force through an experimental method and analytic method. A simulator was developed to imitate beating, shedding, and insertion motions for weaving and the experiment was performed using the simulator. The experiments showed following results: First, the beat-up force increased proportionally as the warp tension increased. Second, the beat-up force increased with the increase of the weft thickness. Third, the beat-up force was exponentially inversely proportional to the weft density. Finally, the beat-up force was increased with the increase of the shedding height. Various experimental and simulation methods were performed to investigate the contribution of the principal weaving parameters to the beat-up force.