In this Phase I Program Pepin Associates extends its aligned discontinuous preform technology to hot structures. Aligned discontinuous preforms allow complex preform shapes to be formed rapidly while retaining mechanical properties for efficient, lightweight structures. This technology reduces the cost of fabricating complex, integrated polymer matrix precursor structures for ceramic matrix composites. Coupled with advanced CMC processing technologies these tailored formable preforms offer the potential for affordable hot structures of complex shape. Pepin Associates and its team fabricate test panels to compare the mechanical properties of 2D and 3D baseline continuous with 2D and 3D aligned discontinuous C/C-SiNC composite laminates. Tension, interlaminar shear, and in plane shear tests are performed at room temperature and elevated temperature. Pepin Associates further demonstrates the ability of the tailored formable preform to fabricate an integrated stiffened skin subcomponent. This subcomponent employs selective 3D reinforcement in a formable preform. Material inspections verify the quality of this precursor structure such that it could be further processed to yield a CMC integrated hot structure. The Phase I program forms the basis for Phase II development of more advanced integrated hot structure and qualification testing and analysis to support the design of affordable complex shaped hot structures to meet NASA requirements.
NASA applications for the aligned discontinuous preform technology include integrated hot structures such as stiffened aeroshells, control surfaces and their attachments, engine components, nozzle extensions and exit cones. More integrated structures for precursor polymer matrix composites will allow greater design flexibility for hot structures. Formable interior cavities would allow passive and active cooling of hot structures.
DARPA and the Air Force are developing a hypersonic air breathing weapon concept (HAWC) and a tactical boost glide vehicle (TBG). The Army is developing an ultrafast maneuverable long range missile launched from a ground platform. The low cost integrated structures developed in this Phase I program will create more design/manufacturing flexibility for these DOD hypersonic programs.