By: Tanveer Malik and Shivendra Parmar

Department of Textile Technology
Shri Vaishnav Institute of Technology and Science
Baroli (Indore-Sanwer Road), Distt: Indore (M.P) Pin-453331

ABSTRACT

When building bridges, airplanes and other structures engineering designers draw detailed plans on computers and use stress analysis to work out the effects of all the likely forces. In contrast, textile fabrics and textile products are still produced largely on the basis of experience, intuition and trial and error. Many textile fabrics have now penetrated into high performance areas from medical to civil engineering, from leisure to military and from space to undersea. These demanding areas require textiles to be engineered very carefully and precisely since failure could have fatal consequences. The 3-D fabrics are very challenging for these fields nowadays and will be a demanding technology in coming days.

3-D fabrics are technical textiles made on 3 planar geometry on contrary to 2-D fabrics which are weaved in 2 planes. In 2D fabrics, yarns are weaved perpendicularly, but in 3-D fabrics, yarns are not only weaved perpendicularly but also at an angle with each other depending upon the requirement.

Multi-warp weaving methods are used for weaving angle interlocked multi-layer 3D woven fabrics and can be constructed using specialized looms such as a reciprocative loom, and a conical take-up device.

Historically, applications of 3-D fabrics were restricted to aerospace development but nowadays these find applications commercially, particularly in marine structures and industrial components.

Scientists believe 3D woven preformed parts will be a key technology in achieving almost 100% atomization in respect of the manufacturing of complex shaped Composite parts.
This paper includes weaving methods, properties and applications of 3D fabrics in todays and coming era.

INTRODUCTION

Three-dimensional woven, braided or stitched fibrous assemblies are textile architectures having fibers oriented so that both the in-plane and transverse tows are interlocked to form an integrated structure that has a unit cell with comparable dimensions in the all three orthogonal directions. This integrated architecture provides improved stiffness and strength in the transverse direction and impedes the separation of in-plane layers in comparison to traditional two-dimensional fabrics. Recent automated manufacturing techniques have substantially reduced costs and significantly improved the potential for large-scale production. Optimal orientations, fiber combinations and distributions of yarns have yet to be fully developed and perfected for 3D fabrics subjected to impact loading conditions.

The term �three-dimensional� is applied in the sense of having three axes in a system of coordinates. If no yarn system penetrating the depth is present, we are confronted with a simple textile flat (2-D) fabric. Simple flat fabrics have very good stiffness and strength in two directions i.e. in warp-way and weft-way, but they have problem in thickness direction. In thickness direction they have very low stiffness and strength.

2. 3-D Glass fabric can be applied in areas where high strength and/or weight reduction is needed and can act as an alternative to plywood, balsa, solid laminate, honeycombs, foams and more.

3-D WOVEN COMPOSITES

While the performance advantages of 3D composites are recognized, past applications have been restricted due to the high cost of producing the 3D reinforcement. Historically, applications that can afford the performance advantages have been restricted to aerospace development, typically including RTM (or other infusion). Recently, these materials have been finding increased usage in more commercial applications, particularly in marine structures and industrial components that are very cost sensitive. Due to the availability of heavy weight fabrics/reinforcements, and the subsequent reduction in lay-up labour, 3D fabrics can reduce the cost of finished composite structure.

The increasing interest and use of 3D textile composites is attributed to two factors: 1) improved performance due to controlled fiber distribution; and 2) lower cost through the use of automated textile processing equipment. Compared on a cost per square foot of finished composite structure, 3-D WEAVE reinforcements consistently outperform traditional 2D materials.

Application of 3-D woven composites

� In the marine company for building recreational boats.
� For manufacturing industrial pressure tanks.
� Alternative to a corrugated steel structure for the industrial/infrastructure market.

COMPARISON OF PROPERTIES OF 3-D WITH 2-D FABRICS

1. The absence of interlacing between warp and filling yarns allow the fabric to bend and internally shear rather easily, without buckling within the in-plane reinforcement which is not in case of 2-d fabrics.
2. The presence of Z-direction reinforcement in 3-d fabric is an obvious advantage, as dramatic improvement in composite transverse strength and impact damage tolerance is well documented. For example, tests of laminates made from these preforms have shown a 10�30% increase in short beam shear strength over 2D textile laminates.
3. These have shown improved compression after impact strength, reduced delamination area, and increased number of sub-perforation energy blows required to penetrate the panel.
4. Composites made from 3-d preforms exhibit high fiber content (% by weight). Although somewhat lower percentages can be expected, fiber content is still higher than in composites made from comparable 2D fabrics.

APPLICATIONS OF 3-D FABRICS

With completely controlled and tailor able fiber orientations in the X, Y and Z directions, the ability to weave aramid, carbon, glass, polyethylene, steel fibers etc. and any hybrid combination, thickness up to one inch (2.54 cm), width up to 72 inches (183 cm) and the ability to make net shapes, an almost infinite number of 3-D materials are possible with a tremendously wide range of performance.