3-D Fibrous Assemblies

Properties, Applications and Modelling of Three-Dimensional Textile Structures

Jinlian Hu

• Publisher: Woodhead Publishing
• Year: 2008
• Print ISBN: 9781845693770
• eBook ISBN: 9781845694982
• Topic: Tecnología e ingeniería
• Subtopic: Ciencias de los materiales

There have been important recent developments in the production and application of three dimensional fabrics. These 3D textile structures have great potential for new fabrics and textile applications. 3D fibrous assemblies summarises some key developments and their applications in the textile industry.The book begins with an introductory chapter which defines the concepts and types of 3D fibrous assemblies. The book then discusses how 3D fabrics can be applied in textile products. These range from composites and protective clothing to medical textiles. The remainder of the book reviews the two main 3D fabrics; multi-axial warp knitted fabrics and multi-layer woven fabrics. Themes such as structure, manufacture, properties and modelling are considered for both fabrics.Written by a distinguished author, 3D fibrous assemblies is a pioneering guide for a broad spectrum of readers, ranging from fibre scientists and designers through to those involved in research and development of new generation textile products. - Presents exciting opportunities for the creation of new textiles through the use of three dimensional textile fibre assemblies - A comprehensive account of the different types of 3D fabrics and their associated structure, properties, manufacture and modelling - Examples of how three dimensional fibres can be applied in textile products

1

Introduction to three-dimensional fibrous assemblies

Abstract

Three-dimensional (3-D) textiles are those materials that have a system or systems in all three axes of plane. These materials offer particular properties, such as interlaminar shearing force, mechanical and thermal stability along all three axes of space, that are not achievable with other reinforcements. The development of three-dimensional textiles has taken place rapidly over the past two decades. It can be credited largely to the growth of another technology: composite materials, which combine fibres and a matrix. An understanding of the production methods and structures of these 3-D fibrous assemblies would go a long way in design, process control, process optimization, quality control, clothing manufacture and development of new techniques for specific end uses. This chapter introduces various 3-D woven, knitted, non-woven, braided and stitched fabrics with their brief description and advantages.

Key words

three-dimensional (3-D) textiles

3-D woven fabrics

3-D knitted fabrics

3-D non-woven fabrics

3-D braided fabrics

1.1 Introduction: concepts of three-dimensional fibrous assemblies

Textile structures such as in woven, knitted, non-woven and braided fabrics are being widely used in advanced structures in the aerospace, automobile, geotechnical and marine industries. In addition, they are finding wide application as medical implants such as scaffolds, artificial arteries, nerve conduits, heart valves, bones, sutures, etc. This is because they possess outstanding physical, thermal and favourable mechanical properties, particularly light weight, high stiffness and strength, good fatigue resistance, excellent corrosion resistance and dimensional stability. In addition, they act as attractive reinforcing materials in various composite applications with low fabrication cost and easy handling (Tan et al., 1997). With high-end applications such as in aerospace, the orientation of the fibrous reinforcement is becoming more and more important from a load-bearing point of view, as is the need for placing the reinforcement oriented in the third dimension (Alagirusamy et al., 2006).

Textile fabrics, termed preforms in composites and other applications, consist of various reinforcing fabrics such as wovens, knits, braids and non-wovens. Two-dimensional fabrics have allowed us to drape bed, board and body in a profusion of texture, pattern and colour over the centuries. The development of advanced fibres has led engineers to consider textiles for high-performance applications such as in construction and aeronautics. These fabrics have been relatively well developed in terms of production, analysis and application and some of them have long been used in structural composite fields (Chou and Ko, 1989; Mohamed, 1990). However, the strength of these traditional fabrics is anisotropic, manifesting itself primarily in the direction of the fibre orientations. Most of these 2-D textile structures retain the inherent weakness of laminated composites that are susceptible to delamination.

To extend the use and value of textiles into industrial and engineering applications, which typically require strength in more than two directions, textile designers have bound together layers of textiles and exploited the chemical properties of fibres and binders to create novel non-woven textiles whose fibres are not restricted to two-dimensional arrangements. More recently, they have taken the next step: finding ways to manufacture true three-dimensional (3-D) textiles. Hence, 3-D fabrics have been introduced to respond to the needs of a number of industrial requirements such as composites capable of withstanding multidirectional stresses.

The development of 3-D textiles has taken place rapidly over the past two decades. It can be credited largely to the growth of another technology: composite materials, which combine fibres and a matrix. Textile engineers have been challenged to develop strong fibre architectures and new manufacturing processes for building textile structures in three dimensions, as these 3-D fabrics hold great promise for use in industry, construction, transportation and even military and space applications. They are often made into a near net shape so that the overall manufacturing cost can be very low for certain applications (Mohamed, 1990).

An understanding of the production methods and structures of these 3-D fibrous assemblies would go a long way in the design, process control, process optimization, quality control, clothing fabrication and the development of new techniques for specific end uses. The interrelationship between their structure and various properties may be of great help in designing new types of 3-D structures for the construction, medical, sports and aerospace industries.

1.2 Two-dimensional structures (two-dimensional fabrics)

1.2.1 Two-dimensional wovens

Weaving is the most widely used textile manufacturing technique and accounts for the majority of the two-dimensional (2-D) fabric produced (Stobbe and Mohamed, 2003). Woven structures have the greatest history of application in textile manufacturing. Conventional woven fabrics consist of two sets of yarns mutually interlaced into a textile fabric structure. The threads that run along the length of the fabric are called warp or ends, while the threads that run along the width of the fabric from selvedge to selvedge are referred to as weft or picks. Warp and weft yarns are mutually positioned at an angle of 90°. The number of warp and weft yarns per unit length is called the warp and weft density. The warp and weft yarns in a woven fabric can be interlaced in various ways, called a weave structure. The structure in which warp yarns alternately lift and go over across one weft yarn and vice versa is the simplest woven structure, called plain weave (Fig. 1.1(a)). Other common structures are twill and satin weave. Twill is a weave that produces diagonal lines on the face of a fabric (Fig. 1.1(b)). The direction of the diagonal lines viewed along the warp direction can be from upwards to the right or to the left, making Z or S twill respectively. Compared to plain weave of the same cloth parameters, twills have longer floats, fewer intersections and a more open construction. A weave in which the binding places are arranged to produce a smooth fabric surface free from twill lines is called satin (Fig. 1.1(c)). The distribution of interlacing points must be as random as possible to avoid twill lines. The smallest repeat of ...

Table of contents

• Cover image
• Title page
• Table of Contents
• The Textile Institute and Woodhead Publishing
• Copyright
• Woodhead Publishing in Textiles
• Preface
• Acknowledgements
• Chapter 1: Introduction to three-dimensional fibrous assemblies
• Chapter 2: Applications of three-dimensional textiles
• Chapter 3: Multiaxial warp-knitted fabrics
• Chapter 4: Multilayer woven fabrics
• Chapter 5: Tensile properties of multiaxial warp-knitted fabrics
• Chapter 6: Bending properties of multiaxial warp-knitted fabrics
• Chapter 7: Formability of multiaxial warp-knitted fabrics
• Chapter 8: Permeability of multilayer woven fabrics
• Chapter 9: Using multilayer woven fabrics in resin transfer moulding
• Index