Touchstone produced carbon foam (CFOAM), graphite foam (GFOAM) composite core tool materials for evaluating heat transfer characteristics. In addition a high in-plane heat spreader was evaluated along with fiber reinforced bismaleimide (BMI) composite that is the tool surface. The heat source were 300 and 600 W flexible heaters manufactured from glass reinforced silicone and polyimide. The thermal results were collected and submitted to Clemson University and used for validating a 2D model that they developed. After completing the flat panel test a graphite core having DCB geometry was constructed and evaluated for thermal gradients. It was concluded that future development work would be on a tool having GFOAM core and BMI composite surface. The technology readiness level for Phase I started at TRL-1 and ended at TRL-5 based upon a BMI-GFOAM system and that has bottom mount heaters. It is proposed in Phase II to build a segmented 12ft span DCB self-heating composite tool prototype that may be used to validate the technology and provide thin ply composite booms with corrugated geometry in support of NASA LaRC thin-ply composites research.
NASA has expressed interest in improving materials and processes. The intent of this technology development is to provide NASA with a more adaptable, or logistically favorable, process for curing large composite structures. A composite tool that can heat cure large composite structures without autoclave pressure and large ovens is a potential game changer for onsite production needs. The proposed Touchstone self-heating composite tool technology is modular, thus allowing for disassembly, storage, and transportation.
The general approach and specific technologies developed in this STTR can also be applied to other commercial applications such as Airbus A340 & A380 fixed wing leading edges, keel beam ribs, and Boeing 787 pressure bulkheads. Other military Aerospace and Wind applications that demand high stiffness are also potential candidates.