This project will test, evaluate, and demonstrate structural film adhesive alternatives to 3M’s AF 163-2 and AF 191 for Department of Defense (DoD)-specific platforms and applications using production and depot repair materials and processes. These structural film adhesives are needed for many defense applications including fatigue-sensitive and safety of flight components.

These structural film adhesives are sole sourced for use on many DoD platforms due to the high cost of qualification particularly for fatigue-sensitive and safety of flight critical components. No direct replacements currently on the market match all key performance requirements, and any differences in cure, physical, mechanical, and durability properties of alternative adhesives require validation for critical parts. Beyond the years required for full characterization, many applications require application- and/or platform-specific tests before being cleared for flight. 

To reduce dependence on these sole sourced structural adhesives, the performance of a number of existing as well as several recently developed adhesives will be evaluated based on similarities to the physical, mechanical, durability, and fatigue properties of the currently used AF 163-2 and AF 191 products. Performance of adhesives with successful laboratory static and fatigue testing will be demonstrated on tear down and non-critical flight test articles to verify equivalency. Generating a database sufficient to allow substitution by analysis in many applications and demonstrating viability in a teardown test article to support down-selection of alternatives for full-scale testing will work to close the gap between adhesive test and demonstration and between demonstration and transition. 

The most critical use-cases will need to be evaluated beyond the timeline of this project to ensure the adhesives meet unique performance requirements.

Due to their unique combination of physical, thermal, mechanical, and durability properties, structural adhesive films AF 163-2 and AF 191 are sole sourced for use on many DoD platforms, including fighter jets, transport planes, and helicopters. This project seeks to address the supply risk to reduce or eliminate the impact on aircraft availability and readiness. Material testing and demonstration articles will support transition across all of DoD, thus benefiting all services. The ability of DoD maintenance facilities to make structural repairs to flight critical components with alternative structural adhesives rather than purchasing spares from original equipment manufacturers would save the DoD hundreds of millions of dollars. (Anticipated Project Completion - 2027)