Project Start: May 2007
Northrop Grumman Shipbuilding-Gulf Coast (NGSB-GC) designs, constructs, and outfits vessels for the U.S. Navy that include a number of components constructed of composite materials. While these structures improve performance of the Navy’s steel-hulled ships, the infusion process for first-time production articles is largely variable and results in excess material/labor costs and schedule interruptions. This issue will be critically important during construction of the ZUMWALT-Class destroyer (DDG-1000), whose entire deckhouse will be made from composite materials.
The NGSB-GC Project Team successfully used resin flow modeling and simulation software, predicting resin flow behavior and determining optimal production parameters. They developed computer models of each infusion, provided engineering and design services for panel production, instrumented panels with “smart molding” sensors, and fabricated/tested panels to U.S. Navy acceptance criteria. A series of common and complex composite DDG 1000 deckhouse panel-to-panel joints were produced and analyzed. Pilot results indicate that joints fabricated using this technology will significantly improve fabrication quality over historical rework rates, reducing them by over 40%.
The technology successes were immediately implemented in NGSB-GC production processes to support the ongoing DDG-1000 program. They are already providing engineers greater control over resin distribution, tooling and handling, and injection port location. With an estimated key rework reduction of approximately 5,788 hours, a 75% reduction in rework labor for this composite fabrication process is expected. It is also expected that the requirement for 100% inspection of these fabricated composite joints will be eliminated.