STRENGTH AND STIFFNESS OF FILAMENT WOUND FLEXIBLE MATRIX COMPOSITE TUBES

Open Access
- Author:
- Smith, Stephen Daniel
- Area of Honors:
- Engineering Science
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Charles E. Bakis, Thesis Supervisor
Dr. Charles E. Bakis, Thesis Supervisor
Christine Masters, Thesis Honors Advisor
Judith A Todd Copley, Faculty Reader - Keywords:
- composite
carbon
stress
strain - Abstract:
- Rotary wing aircraft (rotorcraft) tailbooms are subjected to aerodynamic and maneuvering loads that cause misalignment along the length of the driveline. The current design of these drivelines accounts for this misalignment by using several rigid aluminum segments connected to each other by flexible mechanical couplings. These couplings not only add weight and complexity, but they are also prone to wear—resulting in their frequent replacement. A proposed solution is to replace the current design with a single flexible matrix composite (FMC) shaft that is able withstand a high bending strain while still being stiff in torsion. By changing to an FMC shaft, the flexible couplings can be eliminated and the overall weight and maintenance of the driveline reduced. Previous research studies on this topic using preliminary materials have found design solutions that meet operational criteria; however these designs employed thick-walled, heavy shafts. In order to reduce the weight of the shaft, a stiffer FMC material is required. One FMC material was evaluated to determine if its properties meet the theoretical results and are sufficient to meet the design standards to be used for rotorcraft driveshafts. Experiments using different fiber layups with the FMC material were done in tension and compression to evaluate stiffness. Results show that a multi-angle laminate tested in compression meets the expected theoretical results for stiffness. However, the same multi-angle laminate does not meet the expected theoretical results for stiffness when tested in tension. Additionally, results show that for a helical laminate with a high Poisson’s ratio, the theoretical stiffness over predicts the experimental stiffness.