Evaluation of Alternative Carbon Fibers to Improve Joint Performance in 3D Woven Heatshields

The successful completion of the Phase I program would directly benefit the Adaptable, Deployable Entry and Placement Technology (ADEPT) and the Heatshield for Extreme Entry Environment Technology (HEEET) programs, both of which are currently focused on the use of 3D weaves in ablative TPS. The identification of an alternative fiber that could be used to both improve strength retention after exposure to high heat fluxes and eliminate the outgassing issues associated with the current use of PAN-based fibers could result in significant performance improvements for the thermal protection system. In addition, the ability to predict strengths for dry 3D woven materials would allow for additional design and analysis to be performed on various heat shield components which could reduce the amount of fabrication and testing that needs to be done to arrive at a suitable design.

In addition to the potential NASA applications, there is also potential for applications within the Department of Defense (DoD). Specifically, Defense Advanced Research Projects Agency (DARPA) is currently investigating the use of 3D woven carbon fiber reinforced composites for aeroshell applications. Depending on the desired trajectory of the vehicle, it is expected that some regions of the vehicle will experience peak surface temperatures that exceed the as-received temperature of the carbon fibers. Therefore, modeling tools capable of predicting the effective material properties and strengths of 3D woven carbon fiber reinforced composites following additional graphitization of the fibers would also be very useful to this community. More »