Wavy Additively Manufactured Continuous Fiber Composite Truss Systems for Enhanced Performance

The need for low cost, reusable Unmanned Air Systems (UAS) is clearly called out in the Air Force 2030 Science and Technology Strategy. AFRL’s push toward the Low Cost Attritable Aircraft Technology (LCAAT) Initiative, its designation as a “Vanguard” program, as well as the follow-on Autonomous Collaborative Platforms Program all address this mission need. The design, fabrication and demonstration of an operational low cost UAS that can be augmented with manned systems is paramount to the mission, but presents challenges around sustainable, scalable manufacturing technology. While the design, build, and fly activities are paramount, AFRL and AFLCMC have a vested interest in the investigation and demonstration of manufacturing processes that will reduce UAS part fabrication and assembly costs. The end goal of this streamlined process is a direct impact on reduced lead time associated with UAS delivery operational units. Amongst the most challenging aspects of aircraft design is the ability to additive manufacture full monolithic parts for many extrusion-based technologies. The technology development plan proposed under the subject SBIR topic will contribute to solving the AF’s mission need around LCAAT, UAS delivery and PiCARD Risk Based Certification. Even if extrusion-based technologies can build monolithic parts, the prevalence of emerging defects will ultimately affect the performance of the component. This is an inherit flaw in many extrusion-based technologies.  However, in order to advance the AF mission for additive manufacturing, performance metrics of complex components are needed if they are going to be certified.  In order to do this, investigating aspects of the building block approach must be done in order to understand the nuances of the technology.  This lies at the heart of the subject proposal which aims at researching and developing new methodologies for the design, additive manufacturing, and certification of topology optimized truss structures made via continuous carbon fiber composites. Towards this goal, new strategies for the manufacturing of truss joints will be investigated using the co-extrusion technology available at ES3 which enables to finely control tow paths and manufacturing parameters. Truss structures will be designed, manufactured, tested, analyzed, and simulated to develop a thorough understanding of the relationship between manufacturing defects and tow waviness, and structural performance. Leveraging testing, X-ray microcomputed tomography, and discrete, mesoscale computational modeling new performance metrics will be developed. This information will be utilized to formulate new design and certification guidelines which can streamline the adoption of topology optimized structures made via additive manufacturing from design to application in AFRL programs.