Non-Polluting Composites Repair and Remanufacturing for Military Applications: Induction-Based Repair of Integral Armor

Report No. ARL-TR-2121
Authors: Fink, Bruce K.; McKnight, Steven H.; Yarlagadda, Shridhar; Gillespie, John W., Jr.
Date/Pages: November 1999; 55 pages
Abstract: Polymer-matrix composite material and structural adhesive repair and manufacturing have significant environmental costs. These costs have recently been documented based on current and anticipated future Department of Defense (DoD) use of these materials. The principal issues for reducing the environmental impact and its associated cost are: (1) reduction in hazardous waste by eliminating shelf-life limitations, (2) reduction in nitrogen oxides (NO(x)) by replacing global heating of the part with localized heating, (3) reduction in volatile organic compound (VOC) emissions by accelerated curing and containment, and (4) reduction in hazardous waste by minimizing production debris through processing step management Induction-based adhesive curing is a potential replacement for current repair and manufacturing methods to resolve the principal issues. The current work establishes that induction heating using conductive mesh susceptors can be used to rapidly cure thermosetting adhesives under a VOC-reducing vacuum condition. It is also established that the presence of these susceptor materials, although not optimized, does not adversely affect the mechanical performance of the bondline when considering the low scatter in lap shear strength. The feasibility of induction-based repair using metallic screen susceptors and the applicability of induction heating to multilayer single-step bonding wherein heat generation is limited to localized bondline regions allowing optimization of repair processes are demonstrated.
Distribution: Approved for public release
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Last Update / Reviewed: November 1, 1999