The U.S. Navy contracted with Northrop Grumman Shipbuilding - Gulf Coast to design, construct and outfit vessels with components constructed of composite materials.
While these structures are required design features, the infusion process for first-time production articles is quite variable and frequently results in excess material, labor costs and schedule interruptions. This issue is—and will remain—critically important for the ZUMWALT-Class destroyer (DDG 1000), whose deckhouse and hanger structure will be made from composite materials.
The Navy ManTech program funded two separate projects supporting the goal of developing predictable and repeatable resin infusion processes for fabricating carbon and vinyl ester composite DDG 1000 ship structures. The first project was for integrated stiffeners for the integrated deckhouse and hanger, which required the development and demonstration of methods for manufacturing large, thick, cross-sectioned composite stiffeners and stiffener joints. The second project focused on panel-to-panel deckhouse joints.
The manufacturing and process parameters for fabrication of the structures are very different, but both project teams developed and analyzed various manufacturing methods and process parameters by using liquid injection modeling simulation and other commercially available software. They validated the modeling and analysis results via test specimen fabrication before proceeding onto fabrication of the demonstration articles.
The manufacturing process parameters developed in both projects have been implemented by Northrop Grumman Shipbuilding – Gulf Coast for the construction of DDG 1000 and are expected to result in significant cost avoidance.