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Braids in history


New trends


Kumihimo groups


Engineering application



Each presentation comprises 15-minute talk and 5-minute discussion using PowerPoint or equivalent slide-show software.

Equipment

A PC with a Windows XP/Vista and a Macintosh OS X are available.
Number of pixel of the projector in the Center Hall is 1024 x 768 (XGA)

Media of your PowerPoint file

•USB flash memory (recommended)
•CD-R
•Transfer via Internet using e-mail (less than 2MB), free file transfer service (less than 100 MB) (recommended).


No other media is acceptable.

Engineering Applications

Chairperson: Asami Nakai

Muratec Braiders for Produce of Carbon Fiber Reinforced Plastics

Tadashi Uozumi

9:45-10:05

Carbon fiber reinforced plastics (CFRP) are used in the advanced industrial field like aircraft, aerospace, racing car as formula 1 due to its character of ultra lightness and high strength. However, in the most production process of CFRP there remains manual procedure that relayed on the personal experience in quality. Therefore it is required to develop new production process to supply CFRP as the industrial products.
Braiding is one of the textile techniques for fabricating performs of CFRP. The braided CFRP indicates superior mechanical properties, as reinforcing fibers in a braid are oriented continuously without cutting them. It was reported that the braided composites indicated the high joint strength and high impact absorption. The other advantage of the braiding is the flexibility of the design of the rigidity distribution. However, to produce the braided CFRP as the industrial products, the production by the conventional batch method is not practical and it is required to develop the new commercial production method. My presentation describes our automatic production system based on braiding technology.
Development of Braided Pultrusion Process

Yoshihiro Takai et al.

10:05-10:25

Pultrusion process is one of the composite production methods to be suitable for mass production. A continuous production with uniform cross sections is maintained by using this process. However, there is little research for pultrusion of continuous fiber reinforced thermoplastic composites (CFRTP). Thermoplastic resin has so high melt viscosity that it is difficult to impregnate into the reinforcing fiber bundles. In these surroundings, we have developed Micro-braided yarn, in which the matrix resin fiber bundles are braided by tubular braiding machine on a reinforcement fiber bundle. Since the resin fiber bundles are directly in contact with a reinforcing fiber bundle, the melted thermoplastic resin could easily impregnate into the reinforcing fiber bundles.
In this study, braided pultrusion products of continuous carbon fiber reinforced polyamide6,6 composites (CF/PA66) were fabricated by connecting the braiding machine to pultrusion machine. We called this process Braiding Pultrusion Process for Thermoplastics “BPP-TP”. We made braided thermoplastic rod by this process, and the impregnation state and mechanical properties were investigated.
Fabrication and Mechanical Properties of Braided Composite Tube

Akio Ohtani et al.

10:25-10:45

Braided fabric proves useful as the reinforcements of fiber reinforced composite materials because of the following features; one of the important features is continuity of the fiber bundle in the braided fabric and this results in higher mechanical properties. Other characteristic is capability of changing the braiding angle according to the requirements. There are many parameters which decide the internal structure and mechanical properties of braided composite such as braiding angle, the distance between braiding yarns, and the cross-sectional shape of braiding yarn. The difficulty arises in that these parameters are not independent value and have the interrelationship with each other.
The purpose of this study is to clarify the relationship between the internal structure and mechanical properties for carbon fiber braided composite circular and rectangular tube. Carbon fiber reinforced braided composite tubes, with different fiber bundle orientation angle (called “Braiding angle”), were fabricated. The cross-section along the braided fiber bundle of the composite was observed and the parameters of the internal structure, that is braiding angle, distance between fiber bundles, and shape of the fiber bundle cross-section (aspect ratio and area of the fiber bundle), were quantified. The bending test was performed for each specimen, and the relationship between the internal structure and the bending properties was clarified. And more, the theoretical analysis were performed by considering the internal structural parameters.
Crushing Performance of 3D Braided Composite Tubes

Y. Yang et al.

10:45-11:05

The energy absorbing performance of braided composite tube with rectangular cross-section is studied in this paper. The tubes, which fabricated by 3D rotary braiding machine were quasi-statically compressed and the crush zones were examined microscopically. Their crushing performance and energy absorption capabilities were compared with that which fabricated by traditional 2D braiding machine in order to evaluated the effect of the 3D braided texture. It was found that the differences of crushing behavior are concentrated on the differences of the length of propagated longitudinal central cracks. Therefore, here, crack area is proposed as a new parameter for square FRP to evaluate the effect on the energy absorption capability. For the braided tubes fabricated by 2D braiding machine, the crack area was getting smaller and smaller with the increasing of braiding angle from 25 to 60. On the other hand, the tubes fabricated by 3D rotary braiding machine obtained higher Es values compared with that fabricated by 2D braiding machine, specially, for those tubes with a small braiding angle. Because the braiding yarns go across through the thickness direction to restrain the crack propagation effectively, as a result, high bending stresses are generated which lead to many fiber fractures and contribute to the total absorbed energy greatly.