Abstract

The LBR-5 software allows optimizing ship structures according to objectives of higherinertia, less weight and/or lower cost. This last criterion offers the choice between two approaches ofcalculation. The first approach is based on a simplified assessment of the cost in which the total costis described by rather simple analytical functions which bring into play on the one hand the designvariables and on the other hand empirical parameters. In the second approach, the calculation of the costis based on data specific to the shipyard. The material cost is analyzed according to the first approachwhile the cost of the labor considers each relevant operation of the ship building with respect to theLBR-5 model. A survey of all the tasks was carried out at Aker Yards France, and a thorough studymade it possible to develop assessment tools of the labor cost for each operation as functions of thedesign variables. Plate straightening operations are also considered in this analysis. This paper presentsa cost-based optimization study carried out on a large passenger ship structure with more than 600design variables, by the use of the detailed approach for the cost calculation. The structural model hasbeen formulated on the basis of technical documentation prepared by Aker Yards France. The loads andstrength criteria applied on the model are considered according to classification society rules (BureauVeritas). Results and conclusions of the study are presented.