基于改进NSGA-Ⅱ的破损沉船起吊力优化

Lifting Force Optimization of Damaged Shipwreck Based on Improved NSGA-Ⅱ

沉船打捞工程中,按照工程经验布置的起吊力参数(位置和大小)容易使得破损沉船起吊时的内力(剪力和弯矩)较大,可能导致沉船起吊断裂,尤其当沉船存在破损时,起吊断裂的可能性大大增加。为此,从梁弯曲理论出发,针对沉船起吊时的受力特点建立了以起吊力参数为输入,以内力分布为输出的沉船内力数值计算模型;基于该计算模型,以起吊力参数为优化变量,以内力峰值为优化目标,建立了起吊力参数优化模型;采用改进的NSGA-Ⅱ算法进行优化计算。以某破损沉船为对象,通过MATLAB实现建模与优化计算,结果表明:优化后的剪力峰值下降约22.72%,弯矩峰值下降约16.13%。

In wreck salvage engineering,the lifting force parameters(location and size)arranged according to engineering experience can easily lead to larger internal forces(shear force and bending moment)of the damaged wreck in lifting,which may cause the lifting of wreck to break.Especially when the wreck is damaged,the possibility of lifting and breaking greatly increases.Therefore,starting from the theory of beam bending,a numerical calculation model of the internal force of the wreck was established according to the force characteristics during lifting,with lifting force parameters as the input and internal force distribution as the output.Based on the proposed calculation model,a lifting force parameter optimization model was established with the lifting force parameter as the optimization variable and the peak internal force as the optimization objective.The improved NSGA-Ⅱalgorithm was used for optimization and calculation.Taking a damaged shipwreck as the object,the modeling and optimization calculation were carried out by MATLAB.The results show that the peak value of shear force after optimization decreases by 22.72%and the peak value of bending moment decreases by 16.13%.