EWL组合近似模型在铝车身轻量化优化中的应用

Lightweight Design of Aluminum Automotive Body Based on EWL Ensemble Surrogate Model

以铝车身为研究对象,基于详细接头建立了铝车身参数化概念模型,其与车身详细模型的误差控制在15%以内,满足工程开发要求。采用相对灵敏度分析法筛选出铝车身的8个关键断面作为设计变量。提出EWL组合近似模型;运用最优拉丁超立方设计(Optimal Latin Hypercube Design,OLHD)采样法分别建立基础性能的KRI、响应面法(Response Surface Methodology,RSM)、径向基函数(Radial Basis Function,RBF)法、反比例平均化(EI)法、启发式计算(EG)法和EWL组合近似模型,通过对比分析误差评价指标得出EWL组合近似模型具有最优的拟合精度和稳定性。综合运用EWL组合优化模型和组合优化算法,即全局自适应模拟退火算法(Adaptive Simulated Algorithms,ASA)和梯度序列二次规划(Non-linear Programming by Quadratic Lagrangian,NLPQL)法的组合优化策略对参数化概念铝车身模型进行轻量化优化。结果表明,在4项基础性能不降低的情况下实现铝车身质量减轻6.7 kg,占整车质量的6.58%,且试验误差控制在10%以内,取得了较好的轻量化效果,为概念设计阶段的铝车身轻量化设计提供指导。

The paper focuses on an aluminum alloy car body and initially,a parametric conceptual model of the aluminum alloy body was established,taking into account the joint details.The discrepancy between the model and the detailed vehicle body model is maintained within a 15%margin,which meets the requirements of engineering development.Utilizing the relative sensitivity analysis,eight critical sections of the aluminum alloy body were selected as design variables.Then the EWL ensemble surrogate model was proposed,and the surrogate models for fundamental properties,including KRI,RSM,RBF,EI,EG and EWL,were developed respectively using the OLHD sampling method.Upon comparing the error evaluation indexes,it is evident that the EWL ensemble surrogate model exhibits the highest fitting accuracy and stability among the six approximation models.Finally,the parameterized conceptual aluminum body model underwent lightweight optimization using the combination of the EWL ensemble surrogate model and a combinatorial optimization strategy,which consists of the global ASA annealing algorithm and the NLPQL method.The results show that the weight reduction of the aluminum alloy body is 6.7 kg without compromising the four fundamental properties.This reduction accounts for 6.58%of the vehicle's total weight,and the error in test verification is maintained within a 10%margin.The proposed method has achieved a better lightweight outcome,offering valuable insights for the lightweight design of aluminum car body in the conceptual design stage.