A MICRO-MECHANICAL MODEL OF KNITTED FABRIC AND ITS APPLICATION TO THE ANALYSIS OF BUCKLING UNDER TENSION IN WALE DIRECTION:MICRO-MECHANICAL MODEL

The typical micro-knitting structure of knitted fabric,which makes it very different from woven fabric,is described.The tensile tests of knitted fabric are reported.The deformations of the micro-knitting structures are carefully studied.The study indicates that when a knitted fabric sheet is subjected to a tension along w-direction an extra compressive stress field inside loop in c-direction is induced.The extra stress field is also determined through analysis.Finally,a micro-mechanical model of knitted fabric is proposed.This work paves the way for the simulations of buckling modes of a knitted fabric sheet as are observed in experiments.

Tensile Properties of Weft Knitted Fabric Reinforced Composites

Seven kinds of weft knitted fabrics from glass fiber yarns were used as reinforcement to make fabric/epoxy composite laminates. Tensile tests were carried out to examine and compare the mechanical properties in course and wale direction of these composites. On the basis of experimental results, attempts have been made to analyze some main factors influencing stress-strain curve, ultimate tensile strength and initial elastic modulus of specimens.

Investigation on the Dimensional Properties of Relaxed Plain Knitted Fabrics

A geometric model of relaxed plain-nitted fabric isproposed.A method based on the model for predictingthe loop length from the course spacing,wale spacing offabric and the diameter of yarn is deduced,as well as a computer program is developed to graphically represent the structures of plain knitted fabric with various struc-tural parameters.

Wet Permeability and Moisture Vapor Transmission Characteristics of Soybean Knitted Fabrics

Wet permeability of fibrous assembly is mainly influenced by the properties of liquid and the configurations of the fiber which consist of diameter of fiber, twist angle and fiber alignment in a yarn. It can be seen from experimental results that the knitted fabric made of soybean (SB) fiber has goodproperties both in wet permeability and vapor transmission so that the knitting technology and fabric characteristics can be improved.

Finishing Effect on Warmth Property of Cotton/Kapok Blended Knitted Fabric

Nowadays,more and more natural or functional fibers are being investigated due to their utilization in thermal underwear.Kapok fiber is one of the natural cellulosic fibers whose source is the kapok plant. It has hollow body and sealed tail,which exhibits desirable features required for functional textiles of this nature. In this study,cotton / kapok( 80 /20 by mass) blended yarn with two types of yarn size 18. 5 and 14. 8 tex,respectively are knitted into plain stitches. The fabrics are undergone with an optimal preparation plan according to orthogonal design. Then,after dyeing and softening,fabric properties including thermal and water-vapour resistances, wicking property, pilling behaviour, and surface morphology,are tested and scrutinized for their candidacy for thermal underwear. The results showed that cotton / kapok blended fabrics have good thermal resistance which is significantly higher than those of cotton / modal blended fabrics,and the same water vapour resistance compared with cotton / modal blended fabrics which are normally used as underwear. Cotton / modal blended knitted fabrics has better pilling grade than cotton / kapok blended fabrics. Meanwhile, the cotton / kapok blends fabrics have good wicking property. Collectively,it was concluded that cotton / kapok blended fabric was appropriate for thermal underwear. However,the main limitation of these fabrics is their pilling properties.

A micro-mechanical model of knitted fabric and its application to the analysis of buckling under tension in wale direction:buckling analysis

With the aid of the micro-mechanical model of knitted fabric proposed in Part 1 we analyze the buckling of a knitted fabric sheet when it is subjected to a tension along the wale direction. The large deformation of the fabric sheet in the critical configuration is considered and, to avoid possible deviation due to the approximation of the theory of thin plate, the three-dimensional theory of instability is used. The fabric sheet is considered as a three-dimensional body and all boundary conditions are satisfied. It is shown that the buckling of the fabric sheet is possible, two buckling modes and the corresponding buckling conditions are obtained, but only the flexural mode is physically possible as observed in experiments.

Effect of Run - in Ratios on the Mechanical Properties of Two - Guide Bars Warp - Knitted Fabrics

Warp knitting technology gets rapid development at present and becomes one of the most important parts of the textiles.But it is less known how the parameters of warp knitting technology affect the mechanical properties of warp-knitted fabrics.This paper presents discuss a research on the relationships between run-in ratio and mechanical properties of the two-bar warp-knittedfabrics through the measurement and analysis of the mechanical properties of various samples with different run-in ratios.The optimal run一in ratios for the reasonable mechanical properties are obtained from above dis-

Application of Bi-axial Warp Knitted Structures in Concrete Constructions

The warp knitted bi-axial directionally oriented structure (D. O. S. ) reinforcement substrates applied to building construction are discussed in comparison to woven fabrics. One of usage barriers of reinforced cement with gloss-grid is its sensitivity to alkali existed in the cement which will lead to the reduction of its service-life. The tests show that the treatment by sol-gel method to protect the composite from alkali corrosion is effective. Then two formulae of sol-gel solution are also recommended here for application.

Flexural Properties of Weft Knitted Fabric Reinforced Composites

Several different kinds of weft knitted fabrics from glass fiber yarns were used as reinforcement to make fabric/polyester composite laminates. Flexural tests were carried out to examine stress- deflection process and compare the mechanical properties in course and wale directions of these composites. The experimental results indicate that the numbers of load-bearing yarn in course and wale direction and the fabric density are the main factors influencing the ultimate tensile strength and initial elastic modulus of specimens.

Investigation of Different Washing Effects on Physical and Mechanical Properties of Cotton Knitted Garments

This paper deals with three types of washing (enzyme, softener, Silicone) effects on 100% cotton Single Jersey T-shirt, Slub Single Jersey T-shirt, Double Lacoste (5% Lycra) Polo shirt, Single jersey CVC (T-shirt) and PC single Jersey (T-shirt). Typical industrial washing procedures and techniques were followed and then physico-mechanical properties were analyzed under standard condition. It is observed that after washing, weight of each garments has increased from 5% to 36%;stitch length of the constituted fabric has decreased from 1% to 10% approximately;CPI has increased 23% for CVC fabric only for enzyme treatment and for other process it has a little bit or no wash effects. Same effects found for WPI except 100% cotton and Double Lacoste. Shrinkage property both for lengthwise and widthwise remains the same except CVC and Double Lacoste knitted garments and spirality has almost unchanged except 100% cotton and slub fabric. Both the dry and wet rubbing properties have improved after any types of wash except 100% cotton on Silicone wash. Water absorbency property has increased;pH of all the samples is under controlled and lies between 4.5 and 5.0. But there is no significant change of colorfastness to wash and stain after these washing treatments.

Comparative Study of Polypropylene Non-Woven Surgical Mask and Locally Manufactured Woven and Knitted Fabrics Facial Masks

The outbreak of coronavirus has led to an increase in the demand for facemasks globally. Unavailability of appropriate polypropylene non-woven fabrics face masks as a result of inadequate supply to satisfy the growing population has brought about the manufacturing of locally fabrics masks to augment or substitute standard medical class facemasks. The study aims at analyzing airflow of these locally manufactured fabrics to determine possible means of transmitting the virus as well as establish comfort of the user of these masks. Standard polypropylene non-woven, woven and knitted fabrics were considered for the study. Air permeability test was conducted on these fabrics using Frazier Air permeability tester. Depending on the property significant variation in the textile fabrics, polypropylene non-woven is widely accepted for facial masks. Nevertheless, this study illustrates that woven and knitted fabrics have more open structures, which allow a high rate of air penetration and so may require two or three layers to prevent antimicrobial or antiviral potential.

A STUDY OF FINE DENIER POLYPROPYLENE FIBER KNITTED FABRICS' WET COMFORT——THE WET COMFORT STUDIED BY THE NORMAL OBJECTIVE TEST

Based on the theory of moisture vapor permeability and liquid moisture transmission through fabric, this paper is mainly concerned with the wet comfort of the fine denier polypropylene fiber knitted fabrics. The liquid water transport property the liquid water retention property, the moisture permeability property, the moisture releasing and drying property of these fabrics are tested by normal objective ways and discussed. At last, according to these properties these fabries are classified by grey model synthetic evaluation method.

APPLICATION OF COMPOSITE FIBRE TO HIGH ELASTIC KNITTED FABRIC

The knitting condition and technology for PBT/PET composite fibre on loop wheel machine as well as the effect of knitted fabric structure and stitch parameter are discussed in this paper. The properties of high elastic plain knitted fabrics are also discussed.

STUDY ON THE METHOD FOR EFFECTIVELY QUICK DETECTING THE EVENNESS OF A KNITTED FABRIC

In this paper,the relations between the parameters of stitch structure and the needle penetra-tion force,and the method by using the needle penetration force detected to evaluate the looplength and evenness of knitted fabric indirectly are analysed and discussed.A microcomputer system with a needle sensor and author’s program are used as a pick up setcombined with a data analysis system,for sampling and analysing the needle penetration forcedata.A lot of experimental research work has been done for knitted fabric of some kinds of knittedstitch and loop length.As a summary of this study,some conclusions can be drawn from the linearregression between the needle penetration force and the loop length.Then,the size and evenness ofthe loop length of knitted fabric can be indicated indirectly by detecting the value and variance ofneedle penetration force.It offers an effective method to detect and evaluate the evenness of knit-ted fabric with an efficiently high speed.

Analysis of the Thermohydro - comfort Durability for Microfil - polypropylene Knitted Fabric under Grey System

Thin microfll - polypropylene knitted fabric that is knitted to use new single plated theory on large diameter circular weft knitting machine is a new functional fabric. After military use, the reflective opinions are that it is light, thin, soft, smooth - touch, and it has excellent elasticity, good air perviousness, large water vapor permeability . In this paper, an analysis is held to use grey system theory, and the thermohydro - comfort durability of this microfil - polypropylene knitted fabric is compared with that of common knitted fabrics. The analytical result proves the microfil - polypropylene knitted fabric is satisfactory under the climatic conditions that human body needs to eliminate or retain the quantity of heat. It can be use to seam up not only physical ability training uniform of serviceman but also civil sporty and sportswear et cetera.

Effect of PLA Knitted Structure on the Mechanical Properties of Composite Vascular Scaffold

A new entire biodegradable scaffold has been developed which does not require precelluiarization before transplantation. This new kind of vascular scaffold prototype made from porous poly- e-caprolactone （PCL） membrane to provide three-dimensional environment for cell growth, and embedded with weft-knitted polylactic acid （PLA） fabric to support mechanics. The aim of this paper is to study the variation tendency of mechanical properties with the fabric spacing changing. The basic geometrical parameters were measured to characterize properties of the samples. The tensile and compressive elastic recovery of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. Both tensile and compressive properties enhanced when reducing the fabric spacing of the composite vascular scaffold.

Computer-aided Pattern Design of Multi-bar Warp Knitted Fabrics

To meet the development trend of multi-bar warp knit-ting machine towards high-speed,advanced technologyand computer control and the requirements of variousproducts with small quantity,there are many researcheson the computer-aided pattern design of multi-barwarp knitted fabrics.In terms of the special propertiesof the computer-aided pattern design of multi-barwarp knitted fabrics,the Object Oriented Program(OOP)programming-Object Windows class Library(OWL)programming is selected.According to thecharacters of the OWL programming,various functionsare defined.Pattern design and technical parameters canbe output,which offers a great convenience for the fac-tory.

Study on Anisotropy and Punching Yield Strength of Knitted Fabrics

In terms of the structural characteristics, knitted fabrics are described as plane orthotropic body with two symmetric axes, and the stress in different direction is approximately linear with strain before the yield point.The punching yield strength can be predicted theoretically by developing a mathematical equation from anisotropic effect of knitted fabrics. The experimental results demonstrate the applicability of theoretical formula. Analyses also reveal that the factors influencing three-dimensional deforming performance can be divided into two categories: fiber-yarn-fabric structural features and deforming condition.

Study on Wet Permeability Models of Yarns and Knitted Fabrics

Water transport through the pore structure of the knitted fabric can occur only in place where the fiber-water surface attraction force is greater than the water weight in the capillary. To investigate wet permeability of the knitted yarn in the fabric, a liquid transport model is established. The main factors which have significant influences on the liquid transport have been analyzed. It is derived from the argument that the optimal design for the knitted fabric with quick sweat transport property can be obtained.

Influence Factors on the Moisture Transmission of the Pure Polypropylene Knitted Fabrics

This paper analyses the principle of wicking effect of the polypropylene filament yarn. By means of theoretical and experimental analysis, some factors affecting the moisture transmission of the pure polypropylene knitted fabrics are discussed.