摘要
船体板架结构在屈曲约束下的优化问题具有变量多和约束多的特点,且屈曲计算需借助有限元分析,属于大规模耗时优化问题,运用常规优化方法求解需要较高的计算成本。这里提出一种适用于屈曲约束下船体板架快速优化方法,该方法利用板格屈曲利用因子具有局部性的特点,对板格厚度自变量空间进行降维处理;利用板格屈曲利用因子对板格厚度具有单调性的特点,采用牛顿迭代方法求解其达到目标值的板格厚度;同时比较板格在相同重量增量下,加筋叠加板厚与仅加板厚对屈曲利用因子改善程度的大小决定是否加筋;通过两阶段的迭代寻优,快速获得最优的板厚以及防屈曲筋布置方案。某油船双层底优化结果显示,该方法能够在30步之内完成优化计算,优化效率高;优化方案相比原始方案减重达17.63%,绝大部分板格屈曲利用因子取值在0.9~1.0之间,材料得到充分利用。
The optimization of a ship grillage structure under the constraints of buckling utilization factor with finite element method for buckling analysis possesses the characteristics of many variables and constraints,which is an expensive large scale optimization issue.It is computationally prohibitive to solve this optimization problem using the conventional optimization method.To this end,a novel fast optimization approach for ship grillage structure under the buckling constraint is proposed.Using the locality of the panel buckling utilization factor,the variable dimensionality can be reduced while using the monotonicity between the buckling utilization factor and the thickness of a buckling panel.The Newton iterative method can be applied to obtain the thickness of buckling panel with the buckling utilization factor reaching the expected value.Meanwhile,the configuration of anti⁃buckling stiffener is decided by comparing the improvement degrees in the buckling utilization factor of adding anti⁃buckling stiffener and thickness together with adding thickness only under the same mass condition.Through two⁃stage iterative optimization,the optimized scheme of the thickness of buckling panel and the anti⁃buckling stiffener setting can be determined quickly.The optimization results of double bottom structure of an oil tanker show that the optimization can be done in less than 30 steps,which demonstrates the effectiveness of the proposed approach.The weight of optimal scheme is reduced by 17.63%compared with the original scheme,and most of the panel buckling utilization factors of the optimal scheme are between 0.9 and 1.0.Materials are fully utilized.
作者
韩涛
汪俊泽
王元
易家祥
吴嘉蒙
程远胜
刘均
HAN Tao;WANG Junze;WANG Yuan;YI Jiaxiang;WU Jiameng;CHENG Yuansheng;LIU Jun(Marine Design and Research Institute of China,Shanghai 200011,China;School of Naval Architecture and Ocean Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《海洋工程》
CSCD
北大核心
2021年第3期42-50,134,共10页
The Ocean Engineering
关键词
船体板架
屈曲利用因子
优化设计
板格厚度
加筋
ship grillage
buckling utilization factor
optimization design
thickness of buckling panel
anti⁃buckling stiffener
