Development of Fire Safe Resins for Submarine Applications

Composite structures are often made of sandwich construction composed of a core and two face sheets. The traditional phenol processing approach results in laminates with excessive voids and reduced mechanical properties. Additionally, a robust FSTsafe (fire, shock, and toxicity) core material for submarines does not exist and must be developed using materials that are already commercially available. The objective of this phased Navy ManTech Composites Manufacturing Technology Center (CMTC) effort in support of the VIRGINIA Class submarine (VCS) is to improve and demonstrate the manufacturability of an internal submarine article using the FST-safe resins. Some existing systems have been approved for use within the pressure hull of a submarine but the systems frequently have too many voids to be reliable. This project will identify improved manufacturing processes to reduce the phenolic void content and improve the design allowable. The second purpose of this effort is to identify novel commercially available materials and approaches to bring composite within the pressure hull affordably. Both the new processes and new materials will be screened using a cone calorimeter and then demonstrated on a doubly curved article. Mechanical properties will be generated to replace the outdated design information based on the legacy phenolic resin process.

The result of this effort will be the processes, methodologies, and materials to be used to bring composites within the pressure hull. Those subsequent applications will allow for the removal of metal components in highly corrosive environments, therefore, reducing the life-cycle costs of the submarines. The manufacturing improvements made to phenolic core systems and phenolic laminates can be leveraged to applications industry-wide and provide far-reaching improvements to multiple DOD platforms.

This project will transition to a follow-on project for point insertion. This follow-on effort will be S2679 Fire Safe Resins Phase 2 and is currently pending. Implementation will occur at General Dynamics Electric Boat (GDEB) with an anticipated date of 2019 on SSN 794. Initial work has been completed to develop implementation targets for the follow-on phase. A production vendor will be sought to demonstrate the techniques developed by the team in a production environment.

*Prepared under ONR Contract xxxxxx-xx-x-xxxx as part of the Navy ManTech Program.

*DISTRIBUTION STATEMENT A. Approved for public release: distribution unlimited. DCN# xxxx-xxx-xx