Automated Manufacture of Damage Detecting, Self-Healing Composite Cryogenic Pressure Vessels

During Phase I, Aurora Flight Sciences and the University of Massachusetts Lowell propose to demonstrate the feasibility of enhancing a commercially available out-of-autoclave (OOA) carbon prepreg material system (e.g. IM7/5320) via embedded structural health monitoring (SHM) and self-healing capabilities, which can be manufactured by an automated fiber placement (AFP) machine. This proposed "smart" material will ultimately enable the cost-effective manufacture of large, lightweight core-stiffened composite cryogenic pressure vessels. Carbon nanotubes (CNTs) will be transferred either directly onto the prepreg, or onto adhesive film plies that are subsequently laminated with the prepreg material. Electrical conductivity measurements via the CNTs will provide embedded SHM capabilities, while localized Joule heating will accelerate self-healing polymerization reactions. The CNT-enhanced prepreg will also serve as a carrier layer to embed well-dispersed self-healing micro-/nano-capsules within the polymer matrix and which will allow for self-healing of microcracks resulting from impact damage and thermal cycling. Self-healing efficiency will be characterized via mechanical testing. This smart material will ultimately be produced in spools of half-inch wide unidirectional prepreg slit tape, and laid down using Aurora's 7-axis, 16-spool automated fiber placement (AFP) machine. Trade studies will be performed on the AFP machine to determine the optimal processing parameters for laying down the smart material. The targeted demonstrator structure, a "smart" cryogenic pressure vessel, will detect microcracks caused by incident impact damage and rapidly repair the damage in situ.

The proposed technology to integrate SHM and self-healing capabilities with a commercially available OOA prepreg material and an automated manufacturing process has several applications within NASA. As identified in this proposal, large composite cryogenic pressure vessels that are part of NASA's Space Exploration program will benefit from this technology by allowing them to be manufactured using lightweight materials in a cost-effective manner. The ability of these structures to repair microcracks in situ will also increase their lifetime and reliability. Other primary and secondary structures including vehicle and habitat module structures will also benefit from the proposed technology. Clearly, after these structures are launched into space, it is often not practical to service them in the event of any damage. The ability to detect damage and to self-heal will be advantageous in such cases. With the success of this STTR program, Aurora will have positioned itself to compete for future NASA contracts that require the manufacture of large, composite space structures similar to the Orion heavy lift launch vehicle, the Space Launch System, and NASA's Commercial Orbital Transportation Services (COTS) vehicle. These structures will also serve as platforms for evaluating other NASA-developed technologies (under Space Act Agreements) such as Carbon Nanosensors and SansEC sensors for SHM, thermal management, and electrostatic discharge prevention.

As an aerospace company, Aurora designs, develops, and manufactures various primary and secondary composite structures for unmanned and manned, military and commercial aircraft. The structures, over repeated load cycles, will develop cracks that affect performance and require significant downtime and maintenance. Being able to integrate SHM and self-healing capabilities with these structures will position Aurora to offer innovative new designs for commercial customers, that are more lightweight and damage tolerant. Furthermore, Aurora could leverage its relationship with major prepreggers such as Cytec, Hexcel, TenCate, and Toray to license the smart material out for subsequent sales to other industries including wind energy, automotive, and construction, where composite materials are being increasingly used. For example, Mega-watt wind turbine blades are being built to lengths of over 90 meters. These blades are repeatedly subjected to very high loads that often lead to cracks. A self-healing blade would minimize the downtime of the wind turbine required for repair and would thus lead to more efficient energy production. Moreover, embedded SHM capabilities would allow maintenance personnel to identify where cracks may be occurring ahead of time, thus preventing catastrophic failure.

This is early/mid-stage (TRL 4) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.