Thermoplastic Composite Panel Repair & Restoration (TCP R&R)

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Infrastructure & Advanced Manufacturing The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: The goal of this R&D effort is to develop an understanding of 1) what types of damage can be incurred in TPC panels, representative of aerospace structures, 2) what types of repairs are possible by leveraging the recyclability/reformability of TPCs, and 3) what types of repairs are best for a given damage scenario enabling restoration of the TPC panel to original strength. A final capstone objective would be to demonstrate a repair of a damaged TPC panel and validate the restoration of its strength through testing. This processing technology would then be repeatable for other types of repairs and integrated with a hand held device or robot arm for transition. DESCRIPTION: Thermoplastic composites (TPCs) are impact resistant, light weight and strong. Unlike thermoset composites (TSC), traditionally used for aero structures, they do not require intensive, time consuming bagging and autoclaving. TPCs can be consolidated (no curing required) out of autoclave and can be stamp formed and welded, further differentiating them from TSCs. In order to meet the demand for high rate, low-cost structures to support CCAs and AAM vehicles, high-rate manufacturing processes are needed; TPCs are the leading candidate material because they can be processed and consolidated by these faster manufacturing techniques. TPCs are also fundamentally different than TSCs, in that they can be remelted and recrystallized repeatedly. While this trait is leveraged to enable welding, it could also be exploited to enable rapid repair. If a crack forms in a TPC panel, due to air battle damage or manufacturing error for instance, TPCs can conceivably be re-melted and re-solidified to enable a fast repair in depot or in forward positions. Repair could be in the form of a reinforcing patch welded over the crack or in the form of material being melted inside the crack for filling and closing. For Phase I, types of representative damage will be identified and simulated in TPC panels (such as surface cracks, through cracks, holes). This will be followed by identifying and designing proposed repairs leveraging the inherent properties of the TPC resin. Proof of concept of a down selected repair option will be demonstrated in the laboratory. Phase II activities could include demonstrating other repair types and mechanical testing of the repaired panel as compared to baseline pristine TPC panels. Increasing the scalability and rate of repair would be a focus of Phase II. Final objectives would be tailoring the repair equipment for integration into robotic arms for automated repair and/or miniaturization of the repair equipment to a hand-held form factor with simple operating rules. Technical goals for Phase 1 to achieve the final objective would be 1.1) classifications and simulation of types of TPC damage, 1.2) a menu of possible repair options identified for each type of damage, 1.3) successful laboratory scale demonstration of a down selected repair type. Phase II technical goals would be 2.1) large scale implementation of the repair and 2.2) validation of the repair as measured by mechanical testing of repaired panels as compared to the baseline and 2.3)integration of the technology to a robotic arm or a hand-held device for simple manual operation. PHASE I: Phase I period of performance objectives and expectations include 1) identification and classification of types of damage that can be incurred by TPC panels either through manufacturing or air battle damage, 2) proposal and design of possible repairs, including the equipment to be use and materials, 3) down selection of an example of damage with it's appropriate repair, 4) proof of concept at the laboratory scale that the repair can be implemented with the damaged panel. PHASE II: The final Phase II objectives/expectations are as follows: 1) the rapid identification of type/class of TPC panel damage and the needed repair, 2) repair equipment that is miniaturized sufficiently to be adapted to a hand-held or robot arm mounted form factor, 3) implementation of a repair that is then 4) validated by mechanical testing of the panel as compared to the baseline, a pristine panel. This process ought to be repeatable for another type of damage/repair scenario as identified in Phase I studies. Finally, areas of improvement will be identified to increase rate/speed of repair process. PHASE III DUAL USE APPLICATIONS: The Phase III effort will involve transitioning the technology to MQ-25 PEO in NAVAIR which is developing a thermoplastic chine for LRIP phase 3 or to DAF CCA PEO which is looking into thermoplastic components for the future. Also, Boeing and DAF are collaborating to develop a land based variant of the MQ-25. REFERENCES: 1. F. Ozturk, M. Cobanoglu, and R. E. Ece, "Recent Advancements in Thermoplastic Composite Materials in Aerospace Industry." Journal of Thermoplastic Composite Materials, vol. 37, issue 9, pg. 3084-3116, 2024. 2. S. D'Urso "Boeing Unveils MQ-25's Land-Based Variant" Published online 16 Sep 2024, accessed 7 Nov 2024 online, in The Aviationist KEYWORDS: thermoplastic composites; composites; thermoplastics; thermoplastic welding; polymer fractures; thermoplastic resins; carbon fiber reinforced polymers;