Open-Architecture Composite Structure
Most amateur high-powered rocket airframes are typically made up of a
composite material. Many make use of fiberglass due to its low weight and
compressibility strengths. Others use the heavier, and albeit stronger,
carbon fiber material. Both work well with the typical amateur rocket;
however, Project Aquila recognized that both had weaknesses in terms of
the design aspects required for the teams rocket. Fiberglass alone would
not provide sufficient strength to overcome the thrust and drag loads experienced
during ascent. Carbon fiber would be able to handle all loads, but is difficult
to fabricate, expensive, and would decrease the mass margin from design
to final rocket.
In collaboration with Auburn University's Departments of Mechanical Engineering and Polymer and Fiber Engineering, Project Tiger Launch has developed a solution to overcome both problems: the open-arcitecture composite structure (O-ACS). O-ACS makes use of the maypole braiding process, a weaving method that uses meshed gears arranged in a circle to carry packages of yarn in an interlaced pattern. This pattern creates a composite lattice structure using yarns comprised of multiple prepreg carbon fiber (CF) tows, which when cured, become a rigid skeletal structure.
The O-ACS will act as the skeleton of the Project Tiger Launch rocket. It's enhanced compressive resistance, compared to that of the typical carbon fiber or fiberglass tube, means increased strength with decreased weight. The O-ACS will be wrapped in a fiberglass sock that will provide the exterior surface of the rocket. This design decreases weight by almost 40% compared to a carbon fiber tube of the same size.
If you would like to learn more about O-ACS, please check out "The Design of Optimal Lattice Structures Manufactured by Maypole Braiding", by Austin Gurley, Ph.D. candidate in Auburn University's Department of Mechanical Engineering, as well as the corresponding patent application.
Last Updated: 11 April 2017