转向节墙式热挤压模结构多目标优化设计

Multi-objective Optimization Design of Resistance Wall Structure in Knuckle Hot Extrusion Dies

针对传统热挤压模具负载强烈、寿命低下的问题,在综合传统闭式挤压与开式飞边结构优点的基础上,提出挤压模具上的新型飞边结构——阻力墙结构。采用径向基函数近似模型方法结合遗传算法作为组合优化策略对转向节热挤压模具上的阻力墙结构参数开展多目标优化研究,以期找到最优的结构参数组合,充分发挥阻力墙结构在填充性和模具寿命方面的综合性能潜力。首先通过拉丁超立方抽样试验设计,选择了适当的设计参数样本。在对相关核函数拟合效果综合对比的基础上,构建了具有较高精度的以对数路径函数为核函数的径向基函数近似模型。然后将遗传算法引入近似模型进行多目标优化,最终得到了最优的阻力墙参数取值分别为:阻力墙高度h=48 mm,斜度a=0,间隙n=2.5 mm,飞边厚度t=5 mm,桥部宽度b=10 mm。最后通过生产试验验证其正确性。

In order to fulfill the potential of resistance wall in filling capacity and extending die life,it＇s very important to find the optimal combination of structural parameters.The multi-objective optimization was studied using combinatorial optimization strategy which was radial basis function approximation model methods（RBF） combined with genetic algorithm（GA）.Latin hypercube sampling design was applied to select the appropriate design parameters for the FEM experiments.The RBF meta-models were obtained after the comprehensive comparison of the fitting accuracy of five different kernel functions.Then the GA was introduced into meta-models to carry out multi-objective optimization.The optimal parameters of the resistance wall were determined,such as height h=48 mm,inclination a=0,clearance n=2.5 mm,flash thickness t=5 mm and bridge width b=10 mm,which were acquired by weighting function optimization.