worked with Oldenburg Group Inc., which supplied the brackets, as well as Lockheed Martin and Computer Sciences Corp., to redesign the brackets as cast steel components for significantly reduced cost and weight over the welded fabrication. The project created seven po-
tential casting designs that would survive expected static and dy- namic load conditions. According to Akans, the cast design had to be a one-for-one drop-in replacement, using the same material as the weld- ment, which was fabricated from a high strength steel alloy. “In most cases, as long as the new design doesn’t require complete re- qualification and a long list of Navy approvals (i.e., a one-for-one drop-in replacement that doesn’t affect fit, form and function), the decision to pursue the candidate solution is fairly straightforward,” he said. “When re-qualification (i.e., shock testing) is involved, the decision to move forward with the new design is much more dif- ficult to justify.” Once the cast designs were established, the team modeled the casting process to optimize designs and processing conditions. Based on the models, the team selected two of the designs for further evaluation and provided them to Oldenburg Group for implementation. Oldenburg Group plans to conduct
validation trials on the brackets this year. Four American Bureau of Ship- ping (ABS)-approved metalcasting facilities were identified to supply the brackets. After providing a state- ment of work, detailed drawings and specifications to produce the castings to the potential suppliers, Oldenburg Group selected a metalcasting facility to produce the initial cast brackets and will be placing an order this summer. Based on current Oldenburg
Group production experience with the legacy fabricated design and the estimated cost to implement the cast designs for a full ship set of 26 brackets, a cost reduction is antici- pated to be more than 50%. The cast design also will be 33% lighter and use fewer fasteners than the legacy fabricated version.
Jul/Aug 2014 | METAL CASTING DESIGN & PURCHASING | 23
The U.S. Navy and Lockheed Martin intentionally built the first littoral combat ship based on immature ship designs with the purpose of using the first experience building and oper- ating the ship to improve future designs.
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