In order to prevent cracking appeared in the work-piece during the hot stamping operation,this paper proposes a hybrid optimization method based on Hammersley sequence sampling( HSS),finite analysis,backpropagation( B...In order to prevent cracking appeared in the work-piece during the hot stamping operation,this paper proposes a hybrid optimization method based on Hammersley sequence sampling( HSS),finite analysis,backpropagation( BP) neural network and genetic algorithm( GA). The mechanical properties of high strength boron steel are characterized on the basis of uniaxial tensile test at elevated temperatures. The samples of process parameters are chosen via the HSS that encourages the exploration throughout the design space and hence achieves better discovery of possible global optimum in the solution space. Meanwhile, numerical simulation is carried out to predict the forming quality for the optimized design. A BP neural network model is developed to obtain the mathematical relationship between optimization goal and design variables,and genetic algorithm is used to optimize the process parameters. Finally,the results of numerical simulation are compared with those of production experiment to demonstrate that the optimization strategy proposed in the paper is feasible.展开更多
此处 C 是某个常数,J 是 n×n 的全1方阵.用图论的术语可把 A 看成某个 n 阶有向图G=(V,E)的相邻矩阵.即如记 V={x_1,x_2,…,x_n),则弧(x_i,x_j)∈E,当且仅当a_(ij)=1.这样得到的图 G 称为 A 所对应的图.如果 A 是方程(1)在约束(2)...此处 C 是某个常数,J 是 n×n 的全1方阵.用图论的术语可把 A 看成某个 n 阶有向图G=(V,E)的相邻矩阵.即如记 V={x_1,x_2,…,x_n),则弧(x_i,x_j)∈E,当且仅当a_(ij)=1.这样得到的图 G 称为 A 所对应的图.如果 A 是方程(1)在约束(2)—(4)下的解,则对应的图 G 应具性质:展开更多
为了快速评估和提高新型钢铝混合摩托车车架的安全性能,以某款钢铝混合摩托车车架为研究对象,采用HyperMesh软件对其进行性能分析与优化。建立钢铝混合摩托车车架有限元模型,研究钢铝混合摩托车车架在水平载荷、垂直载荷和坐垫载荷3种...为了快速评估和提高新型钢铝混合摩托车车架的安全性能,以某款钢铝混合摩托车车架为研究对象,采用HyperMesh软件对其进行性能分析与优化。建立钢铝混合摩托车车架有限元模型,研究钢铝混合摩托车车架在水平载荷、垂直载荷和坐垫载荷3种工况下的最大应力和最大位移。提出一种以Hammersley采样方法改进传统试验设计方法的哈默斯利采样-试验设计(Hammersley Sampling-Design of Experiment,HS-DOE)法,以钢铝混合摩托车车架主要截面厚度为设计变量,分析其对该车架最大应力、最大位移、模态频率和质量的主效应,获得对目标响应较敏感的设计变量。基于此,以钢铝混合摩托车车架强度和模态频率等为约束条件,坐垫载荷工况最大位移最小化为优化目标,采用OptiStruct求解器对钢铝混合摩托车车架结构进行多目标优化设计,并对优化结果进行仿真分析。结果表明,HS-DOE法可以得到更均匀的样本点,在满足设计要求的前提下,使钢铝混合摩托车车架在水平载荷工况下最大应力减小了41.44%;垂直载荷工况下最大应力减小了16.88%;质量减小了1.88 kg,相比优化前减小了10.23%。展开更多
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.CDJZR14130006)
文摘In order to prevent cracking appeared in the work-piece during the hot stamping operation,this paper proposes a hybrid optimization method based on Hammersley sequence sampling( HSS),finite analysis,backpropagation( BP) neural network and genetic algorithm( GA). The mechanical properties of high strength boron steel are characterized on the basis of uniaxial tensile test at elevated temperatures. The samples of process parameters are chosen via the HSS that encourages the exploration throughout the design space and hence achieves better discovery of possible global optimum in the solution space. Meanwhile, numerical simulation is carried out to predict the forming quality for the optimized design. A BP neural network model is developed to obtain the mathematical relationship between optimization goal and design variables,and genetic algorithm is used to optimize the process parameters. Finally,the results of numerical simulation are compared with those of production experiment to demonstrate that the optimization strategy proposed in the paper is feasible.
文摘此处 C 是某个常数,J 是 n×n 的全1方阵.用图论的术语可把 A 看成某个 n 阶有向图G=(V,E)的相邻矩阵.即如记 V={x_1,x_2,…,x_n),则弧(x_i,x_j)∈E,当且仅当a_(ij)=1.这样得到的图 G 称为 A 所对应的图.如果 A 是方程(1)在约束(2)—(4)下的解,则对应的图 G 应具性质:
文摘为了快速评估和提高新型钢铝混合摩托车车架的安全性能,以某款钢铝混合摩托车车架为研究对象,采用HyperMesh软件对其进行性能分析与优化。建立钢铝混合摩托车车架有限元模型,研究钢铝混合摩托车车架在水平载荷、垂直载荷和坐垫载荷3种工况下的最大应力和最大位移。提出一种以Hammersley采样方法改进传统试验设计方法的哈默斯利采样-试验设计(Hammersley Sampling-Design of Experiment,HS-DOE)法,以钢铝混合摩托车车架主要截面厚度为设计变量,分析其对该车架最大应力、最大位移、模态频率和质量的主效应,获得对目标响应较敏感的设计变量。基于此,以钢铝混合摩托车车架强度和模态频率等为约束条件,坐垫载荷工况最大位移最小化为优化目标,采用OptiStruct求解器对钢铝混合摩托车车架结构进行多目标优化设计,并对优化结果进行仿真分析。结果表明,HS-DOE法可以得到更均匀的样本点,在满足设计要求的前提下,使钢铝混合摩托车车架在水平载荷工况下最大应力减小了41.44%;垂直载荷工况下最大应力减小了16.88%;质量减小了1.88 kg,相比优化前减小了10.23%。
