應用反應曲面法與基因演算法於船體結構構件斷面尺寸之最佳化設計

Optimal Section Scantling Design for Ship Structures Using Response Surface Method and Genetic Algorithm

本文提出一最佳化設計的程序，可解決船體結構構件斷面尺寸最佳化設計的問題。首先，應用田口方法找出對品質特性具顯著影響的因子，作為預測的數學模型的變數；接著，使用反應曲面法建立此數學模型；最後，藉由基因演算法搜尋最佳解，可得到船體結構構件斷面尺寸最佳設計值。本文中並以貨櫃船之擋浪牆結構構件斷面尺寸設計為例，在結構受到負荷後的合成應力、正剪應力和負剪應力的三個限制條件之下，使結構重量最小為設計目標，應用所提出之最佳化設計程序的設計結果，可得到結構重量為16,503kg，比現有設計的結構重量18,098kg減少了8.81%，得到令人滿意的結果。 In this paper, we propose an integrative procedure for solving the optimal section scantling design problems of the ship structures. First, the Taguchi method is applied to find out the significant factors for the quality characteristics as the variables of the predicting mathematical model. Then, the response surface method (RSM) is used to construct the mathematical model. Finally, the genetic algorithm (GA) is adopted to search for the optimal solution for obtaining the optimal section scantlings of the ship structures. In this paper, we also demonstrate the optimal section scantling design of a water breaker structure for the container ship. In this example, under the constraints of the von Mise stress, the positive shear stress and the negative shear stress, the design objective is the minimum weight of the water breaker structure. According to the proposed procedure, we obtain the weight is 16503 kg which is less than the existing weight 18098 kg. The weight of the water breaker structure is, therefore, reduced 8.81%. So, we can get the satisfactory result by using the proposed integrative design procedure.