Braiding is one of the useful textile techniques for fabricating near-net-shaped fiber preforms. Automated braided preform fabrication process has been improved. Triaxial braiding was evaluated as a means of reducing the cost of producing airplane framesusing automation technology. A new preforming process was proposed to make the near-net-shaped preforms by using the conventional tubular braiding technique and deforming technique to change the configuration into the near-net-shapes. The preforms were fabricated with carbon fibers by using the new performing process and molded using resin transfer molding (RTM) process with epoxy resin into I-beam frames and panels for investigating mechanical testing and production cost. Mechanical testing and cost analysis indicated that the mechanical properties of the braided composites are superior to those of aluminum materials and that the combination of the braiding and the RTM process is less costly than the hand-lay-up and autoclave process.

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Surveillance satellites require dimensional stability against temperature variation since the performance of precision optical devices depends on dimensional stability. Dimensional stability can be improved by decreasing the linear thermal expansion of truss structural parts. In this study, a whole truss structure was produced, consisting of several structural units including joints made by using a braiding/resin transfer moulding (RTM) process. Our braiding technologies with a robotic mechanism are capable of braiding not only straight tubes but also divaricate configurations such as of tri-axial truss joints. Braided carbon fibre preforms were moulded using an RTM process with polycyanate resin in order to investigate the mechanical properties and coefficient of linear thermal expansion. Braided carbon fibre-reinforced plastic (CFRP) truss joints and truss structures were produced as examples of aerospace applications by using the braiding/RTM process, in order to evaluate their mechanical properties and carry out structural testing. The modulus and stiffness of braided CFRP truss joints and truss structures were evaluated by comparison with aluminium (Al) and titanium (Ti) alloys. It was clarified that CFRP truss joints have superior specific mechanical and thermal properties as compared to the conventional materials such as Al and Ti alloys. The CFRP truss joint makes the truss structure construction lighter.

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