Advances in Braiding Technology

Specialized Techniques and Applications

Yordan Kyosev

• Editore: Woodhead Publishing
• Anno: 2016
• ISBN:
  9780081004265
• Argomento: Technology & Engineering
• Categoria: Materials Science

Braiding is the process of interlacing three or more threads or yarns in a diagonal direction to the product axis in order to obtain thicker, wider or stronger textiles or, in the case of overbraiding, in order to cover a profile. Braids are becoming the reinforcement of choice in composite manufacturing, and have found a range of technical applications in fields including medicine, candles, transport and aerospace. Building on the information provided in Prof. Kyosev's previous book, Braiding Technology for Textiles, this important title covers advanced technologies and new developments for the manufacture, applications and modelling of braided products.

Part One covers the braiding of three-dimensional profiles, and includes a detailed overview of three-dimensional braiding technologies as well as chapters devoted to specific kinds of 3D braiding. Part Two addresses specialist braiding techniques and applications, and includes chapters reviewing the use of braids for medical textiles and candles. Part Three focuses on braiding techniques for ropes and Part Four reviews braiding for composites. The final part of the book considers modelling and simulation, and covers topics including overbraiding simulation, Finite Element Method (FEM) modelling and geometrical modelling.

• Covers advanced braiding techniques, technical applications, and modelling and simulation of braided textiles.
• Focused on the needs of the textile industry by offering suitable breadth and depth of coverage of a range of braiding manufacturing technology, applications and modelling techniques in a single volume.
• Written by an eminent team of authors, composed of leading scientists and developers in the field who have a wealth of relevant, first-hand experience in braiding, and edited by a high-profile editor who is an expert in his field.

Part One

Braiding of three-dimensional profiles

Outline

1. An overview of three-dimensional braiding technologies

2. Three-dimensional hexagonal braiding

3. Three-dimensional (3D)-maypole braiding

4. Cartesian 3D braiding

1

An overview of three-dimensional braiding technologies

A.E. Bogdanovich North Carolina State University, Raleigh, NC, United States

Abstract

The chapter starts with a brief introduction into braiding technology and establishing principal distinctions between three-dimensional (3D) braiding on one side and two-dimensional (2D) braiding on the other that leads to a simple differentiation principle between 3D and 2D braided fabrics. Then, a detailed overview of the historic origins and major developments in the field of 3D braiding processes and machines is presented. It starts with a more popular “row-and-column” 3D braiding branch, analyzes it in a historic retrospect, and emphasizes major accomplishments and persisting problems. After that, a detailed historic overview of a historically more obscure “rotary” (or “horngear”) 3D braiding branch is presented. Second part of the chapter is focused on the recent 3D rotary braiding advancements, particularly on the main innovations in the rotary braiding methods and novel machine developments, which resulted in a breakthrough of 3D braiding technology. Some novel 3D braided preforms and composites are discussed. Mechanical properties of different 3D braided composites are compared in the final section. The achievements and persisting technical issues associated with 3D braiding in general, and 3D rotary braiding in particular, are summarized in the closing remarks.

Keywords

Braiding machinery; Braiding processes; Composites manufacturing; Textile composites; Textiles; Three-dimensional braiding

1.1. Introductory remarks

It is well understood and documented in the literature that three-dimensional (3D) braided preforms provide unique structural features and performance characteristics to composites. Among those are: full delamination suppression, improved damage tolerance, impact resistance, fatigue life, exceptional torsional resistance, excellent bolt bearing strength, superior skin-stiffener pull-off strength, etc. Complementing these structural performance advantages, the usage of 3D braided integral, seamless, complex near-net-shape or net-shape preforms eliminates a number of labor-intensive operations from the manufacturing cycle, such as cutting and stacking multiple thin (2D) prepreg or fabric plies, tape slitting, or prepregging. In addition, additional manufacturing steps such as through-thickness stitching, z-pinning, etc., become unnecessary. All of the previous should allow for substantial preform cost reductions. After all, combining fully integrated 3D braided preforms with advanced resin infusion techniques such as resin transfer molding (RTM), vacuum-assisted RTM (VARTM), or pultrusion, should make it possible to radically simplify the composites' manufacturing cycle and significantly increase the cost effectiveness. As emphasized by Andrew Head (1998) in regard of the future of 3D braids, “The possibilities are limited only by the imagination!”

After reading the previous, one may reasonably ask: (1) why 3D braids are still not produced in high industrial volumes and (2) why are they still viewed as kind of “curiosity items,” not the prime candidates, when different concurrent composites' designs are evaluated for specific structural applications? It is not easy to answer these questions without a proper understanding of the uniqueness of 3D braided fabrics (regarding their manufacturing methods, dimensions, shapes, fiber architectures, and resulting performance characteristics) within the entire scope of all known textile materials, because that uniqueness determines both the strengths and weaknesses of 3D braids. In this chapter, the author attempts to address some fundamental accomplishments and persisting problems of 3D braiding technology with the primary focus on 3D braiding processes, machines, as well as existing and potential fabric products. Several decades of academic and industrial experience in the field of braiding in general, and 3D braiding in particular, help the author to take a broader look at both positive and negative aspects, and analyze them from different angles and perspectives. The ultimate hope is that this overview will help to understand the history and interconnections, assess the state of the art, and project future developments.

The chapter starts with establishing principal distinctions between 3D braiding on one side, and 2D braiding on the other, which results in a simple differentiation principle between respective braided structures. Then, a detailed overview of the historic origins and major developments in the field of 3D braiding processes and machines is presented. This first addresses what is known as “row-and-column 3D braiding,” mainly in retrospect, but emphasizing those accomplishments and persistent issues which are of a general value for any branch of 3D braiding technology. That category of 3D braiding methods has been flourishing from the late 1960s till the late 1990s, as is evident from the number of issued patents, conference publications, and journal articles, summarized in the book chapters cited in this chapter. During that period, the other principal direction, known under the names “3D rotary braiding” and “3D horngear braiding” (we prefer using the former name here), has been in relative obscurity with only a few valuable patents issued, such as Tsuzuki et al. (1991) as probably the most prominent example. That may look surprising because this direction of 3D braiding has a much longer history and also deep roots in the traditional Maypole-braiding and lace-braiding technologies. Those roots and interconnections are analyzed in detail further in the chapter. In fact, 3D rotary braiding has emerged again only in the early 2000s.

The second part of the chapter is focused on recent 3D rotary braiding developments, which have resulted in a breakthrough of 3D braiding technology and applications. A novel 3D rotary braiding method, machine concept, and control principle have been introduced in 2002 and patented in Mungalov and Bogdanovich (2002). Then, 3TEX, Inc., designed and built two automated 3D braiding machines, in which a bedplate was allowed to be fully populated by fiber carriers. The first machine had 16 horngears and 64 carriers plus 16 axials, and the other had 144 horngears with 576 carriers plus 144 axials. Those two machines opened new horizons for the future 3D braiding technology in several aspects. The first machine demonstrated a reliable ...