船舶坐墩墩木布局及尺寸优化设计

Optimization of docking block placement and dimensions

本文建立了船舶坐墩墩木布局及尺寸优化设计的数学模型,用分级优化方法来求解,其中,外层采用遗传算法确定墩木最佳位置,内层采用序列二次规划方法确定墩木最佳尺寸。讨论了尾部墩木可布置数目、随船下水架刚性和墩木最大容许厚度对优化结果的影响。计算结果表明,增加船体尾部墩木的数目可节省墩木材料;将墩木搁置在适当“软”的基础上,对节省墩木材料和保证船体结构均匀受力有利;增大墩木最大容许厚度可节省墩木材料,但对船体结构均匀受力不利。

A mathematical model for optimizing the placement and dimensions of docking blocks is described. A two-level solution strategy is proposed to solve for the optimal solution. In the first level, the genetic algorithm is employed to determine the optimal positions of docking blocks while the sequential quadratic programming is utilized to obtain the optimal dimensions of docking blocks in the second level. The effects of the numbers of blocks placed in the aft part, the stiffness of the supporting structures on which the blocks are placed, and the maximum thickness of blocks on the design are discussed. Numerical examples show that the increase in numbers of docking blocks in aft part may lead to decrease in total volume of blocks. Placing the blocks on the supporting structures with comparatively small stiffness benefits both the decrease in total volume of blocks and even distribution of loads applied to the ship structures. However, the increase in maximum thickness of blocks gives rise to worse distribution of loads although it may decrease the total volume of blocks.