基于多目标优化方法的FGT管吸能特性研究

Research on energy absorption characteristics of FGT tube based on multiobjective optimization method

为提升舰船反应堆弹性支承结构的抗冲击性,保护反应堆乃至整个舰船的结构安全,对支承方案的吸能结构进行结构优化,通过提升支承结构的综合吸能特性从而实现其抗冲击性优化的目的。利用JLY-6500型号实验机对试件进行冲击试验,基于ANSYS/LS-DYNA软件建立圆柱壳吸能结构试验模型,得到的数值模拟结果与试验吻合。采用目标规划法和功效系数法对多目标优化问题进行求解,对一种新型的具有功能梯度厚度(functional gradient thickness,FGT)的金属管结构进行吸能特性研究。研究结果表明,FGT管在[20 kJ,27.5 kJ]轴向冲击能量范围内各项吸能评价指标(比吸能、冲程效率、平均载荷)都有一定程度的改善,优化效果明显;FGT管在(10°、20°、30°)的斜向冲击下更难进入全局弯曲变形模式,这意味着FGT管有着更大的临界加载角度。优化后的FGT管在大多数冲击情况下,综合抗碰撞性能都优于UT(uniform thickness)管。本文分析结果可为实际支承结构的设计和维护提供参考。

For the purpose of enhancing the impact resistance of reactor support systems,ensuring the structural safety of the reactor and the overall vessel,this study focused on optimising energy absorption structures within the support system.By improving the overall energy absorption characteristics,the impact resistance of a support structure was optimized.The anti-impact experiment was carried out on a JLY-6500 machine,and the experimental model of a cylinder shell energy-absorbing structure was built based on the software ANSYS/LS-DYNA.The result of numerical simulation is consistent with that of experiment.The multi-objective optimization problem was solved by objective programming method and efficiency coefficient method,and the energy absorption characteristics of a new metal tube structure with functional gradient thickness(FGT)were investigated.The results demonstrate significant improvements in various energy absorption evaluation metrics,including specific energy absorption,stroke efficiency,and average load,within an axial impact energy range from 20 kJ to 27.5 kJ.Additionally,the FGT tube exhibits excellent resistance to oblique impacts at angles of 10°,20°,and 30°,making it less prone to global bending deformation.This implies a larger critical loading angle for the FGT tube,indicating its superior comprehensive impact resistance performance compared with traditional uniform thickness(UT)tubes in most impact situations.The analysis results can provide reference for the design and maintenance of supporting structures in practical application.