SBIR-STTR Award

Drive shafts for aerospace platforms are highly loaded, stressed, fatigued, and without question must maintain their operational capabilities. A component of this importance requires a material and design that provides not only a solution to stringent design criteria, but also a high level of confidence to the people who are fielding the platform and ultimately, the end user, service men and women. With properties such as high damage tolerance, operational durability, and extremely high strength and stiffness to weight ratios, these materials are ideal for the high speed and dynamic service conditions that drive shafts operate in. At densities approximately 80% less than steel, 40% less than aluminum, and a Tensile Modulus of 20 Msi, continuous carbon fiber reinforced thermoplastic composites offer the ability to reduce component weight while maintaining the needed strength and stiffness. The proposed manufacturing technique, automated in-situ fiber placement, offers capabilities desirable when manufacturing components that require high degree of accuracy and repeatability. With the high degree of accuracy and repeatability gained by using NC controlled equipment to place the composite tape, combined with its low percentage of labor, the in-situ fiber placement process is an excellent manufacturing approach for highly engineered, precision structures.

Benefit:
The introduction of a thermoplastic composite drive shaft combined with low cost, automated manufacturing processes, posses the ability to not only bring cost down and decrease weight for military drive systems, but also will demonstrate the technology to commercial aerospace as well. Thermoplastic material systems offer increase operational durability to dynamically loaded applications. By using this program as a demonstration of these capabilities, it will show other people that these materials and manufacturing processes can add value to other applications and structures as well.

Keywords:
Damage Tolerance, Damage Tolerance, Ballistic Performance, In-situ fiber placement, Thermoplastic composite, dynamic loading

Carbon fiber/PEEK thermoplastic composite has advantages over both thermoset based composites and metals in the areas of weight, damage tolerance, and manufacturing costs while maintaining solvent and temperature resistance. It is proposed that substituting the existing aluminum driveshafts with carbon/PEEK composite will allow for a lighter, more damage resistant design. Automated Dynamics Automated Fiber Placement (AFP) process allows for continuous curing of the composite as it is laid up using a robotic platform. This allows for composite structures to be fabricated accurately, consistently, and inexpensively. Tooling is greatly simplified compared to thermoset composites and an autoclave post-cure is eliminated altogether. Labor is also greatly reduced when compared to thermoset composites and is equivalent to metal working processes. Analysis from earlier phases will be continued to determine the most efficient layup which will meet all design requirements. Current designs meet all mechanical criteria and achieve a weight savings of 40%. Further optimization is achievable. First article testing will validate the analysis and design tasks. This testing will include static and dynamic loading for both damaged and undamaged configurations. Ballistic testing will be undertaken to validate the analytical models as well as the simulated damage imparted onto the test shafts.

Benefit:
The application of a thermoplastic composite combined with low cost, automated manufacturing processes, possesses the ability to not only lower costs and decrease weight, but also will demonstrate the technology to commercial aerospace companies as well. By using this program as a demonstration of these capabilities, it will show other people that these materials and manufacturing processes can add value to other applications and structures. Analysis and practice has supported the claim that thermoplastic composites outperform both metal and thermoset composites for many applications. This project would provide yet another success story validating this and assisting the technology in gaining acceptance.

Keywords:
Repeatable, Low-cost, Fiber Placement, Automation, Thermoplastic, carbon fiber, Composite, manufacturing