基于可靠性的船体舯剖面鲁棒设计方法

Reliability-based Ship Midsection Structure Robust Design

在不能消灭影响产品质量变化的原因时 ,鲁棒设计方法使产品能适应变化或同时使变化的影响达到极小 ,从而提高产品质量。鲁棒设计必须满足设计要求 ,同时使设计对外界扰动不敏感 ,故鲁棒设计是多目标优化问题。但由于目标和约束函数的不同 ,故它又不同于常规的多目标优化问题。鲁棒设计目标函数为结构响应的一阶导数 ,约束函数也是非线性隐函数 ,因此是多变量的非线性优化问题。涉及到的求导计算太繁琐 ,并且需要计算目标函数的二阶导数 ,所以对这类问题采用含计算梯度或海森矩阵的优化方法是不可行的。本文提出采用自适应随机搜索方法 ,可以有效地进行结构鲁棒设计。应用鲁棒设计思想进行船体结构设计后表明 ,结构具有更稳定的可靠度和质量 。

Robust design attempts to make design insensitive to input variations in the stage of design, which can minimize the effect of variations without eliminating the causes. Structural robust design makes structures unchangeable to variation of variables. It is a multiobjective optimization design, but the objective and constraint functions are greatly different to traditional optimization design. Robust design objective is always structural response′s first derivative, constraint functions are nonlinear functions. It is computationally expensive and impossible to use optimization means which should compute gradient and Hesse matrix, and the second derivative. Through research and experiment, adaptive random seeking method is pointed out to solve the problem. Meanwhile robust design is applied to ship structure design, the result shows robust design is very useful and effective to improve quality of structures.