Contents:|	MARITECH Project: Lightweight Structure for High Speed Ferry
The Swath Concept A Brief History SWATH FAQ's Ride Quality Tri-Hull Development Our Model Testing Maritech Project Lightweight Structure Other |Home|About|Contact|	nder a MARITECH program cost-sharing grant for Process Improvement projects, SI led a 3-company team investigation of the feasibility of applying an innovative structural optimization analysis procedure to the existing SI Super 4000 ferry design, with the goal of achieving significant improvements in the designs structural efficiency. Other members of the project team were: Altair Engineering, Inc. in Troy, Michigan Bollinger Shipyards in Lockport, Louisiana The method of structural optimization was based upon a unique homogenization method conceived by Professor Noboru Kikuchi at the Univ. of Michigan. The basis of the process is the iterative removal of structural material in the specified design space, by the insertion of microscale voids and subsequent analysis of the modified structure's stiffness. Altair Computing, a sister company of Altair Engineering, implemented the theory into a commercial software code known as Altair OptiStruct. OptiStruct uses topology optimization and can create an initial "design" with optimal distribution of structural material. A design obtained from OptiStruct is further analyzed and refined using GENESIS, which is a software package that uses advanced structural optimization techniques to size structures for greater stiffness and effective material utilization. In this project, the parallel mid-body section of the current Super 4000 ferry design was subjected to OptiStruct analysis and the resulting topology was input into GENESIS, where it was sized to improve structural efficiency. Alternative structural configurations were evaluated by SI, Altair Engineering (Altair) and Bollinger Shipyards (Bollinger) in terms of structural efficiency and cost of fabrication and assembly. The project consisted of 10 tasks, subdivided into two phases. The first 6 tasks comprised the first phase, which was to determine the effectiveness of using OptiStruct on the current Super 4000 ferry design. The 4 tasks making up the second phase were oriented towards developing a conceptual computer model which would improve significantly the structural and fabrication efficiency of the Super 4000 design. In addition, it was necessary to develop a finite element model of the existing Super 4000 hull structure because this baseline model was to be used as the "benchmark" against which other structural arrangements would be compared. Several load cases determined to be the worst case conditions were imposed on this model using the NASTRAN finite element solver. The final optimized design selected was compared to the results for the baseline model under the same set of loads, to determine structural adequacy. Bollinger Shipyards evaluated the fabrication efficiency, and cost and ease of manufacturing the optimized design selected. The final structural design chosen, a modified truss approach, was determined to have the best combination of structural performance and cost.
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