基于灰色关联理论的汽车前纵梁塑性成形工艺再设计

Redesign of plastic forming process for automotive fore-carling based on gray relational analysis optimization scheme

研究了汽车V形前纵梁的成形性,对比分析两种压料面工艺补充方案,建立了倒装单动拉深有限元模型。根据数值模拟结果,以压边力、摩擦系数、接触间隙、冲压速度为自变量设计了四因素四水平的正交试验模型,构造了最大增厚量、最大减薄率、最大回弹量与成形质量的关联函数。利用灰色关联分析法获得了多工艺参数对目标函数的关联度,并计算了目标函数的最优解,进而确定了一组最优工艺参数组合。再将最优工艺参数组合代入有限元模型进行模拟验证,较好地解决了起皱、破裂、折叠、局部过渡减薄等缺陷。最后依据几何位移修正回弹法对局部回弹进行了补偿,对模具型面进行了合理的设计变更。生产现场试模显示产品合格,缩短了传统试错法反复试模的时间。

The formability of the automotive V-shape beam was researched. Two kinds of designs of the addendum for the binder surface were analyzed. The FEM model was established with the inverted assembling structure of the forming die. According to the results of the numerical sinmlation, the blank holder force, friction coefficient, clearance between die and punch and punch veloeity were used as inde- pendent variables in the orthogonal experiment. The correlation function of forming quality was designed with the independent variables of the maximum increased thickness, maximum reduction ratio and maximum springbaek amount. The relational grade of various stamping para,neters to relevant objective functions were acquired, the optimized forming parameters were found out using gray relational analysis, and the optimal solution of objective function was calculated, then the optimized forming parameters were input into the FEM model to ver- ify the product defects of wrinkling, rupture, folding, local thinning and soon. Finally the local spring-back was compensated according to the spring-back correction method of geometric displacement and the rational design fo,＂ die face was changed. Identification by on-site mold testing, the end-product was qualified and the forming process was redesigned with less time thau the traditional trial-and-error method.