刘晓晶 杨然 冯章超 王哲

摘 要：针对空间轴线薄壁零件存在的起皱、过度减薄和破裂等质量缺陷，以某汽车的前副车架为研究对象，采用数值模拟和成形试验相结合的方法，对副车架的内高压成形过程进行了研究。研究了弯曲过程中弯曲参数对弯曲成形减薄的影响，分析了轴向进给量、成形压力和加载路径对内高压成形质量的影响。基于有限元模拟得出的最佳参数，进行了弯曲、预成形和内高压成形实验，测量了弯曲圆角外侧和截面变化最大处的壁厚分布，并与模拟结果进行了比较。结果表明，弯曲成形时弯曲外侧容易出现过度减薄和破裂，可以通过优化弯曲参数改善。模拟结果和实验结果基本吻合，两者在典型截面处的壁厚分布整体变化趋势一致且两者壁厚最大差值为6%，表明该优化方案是可行的，可有效指导副车架的生产实践。

关键词：前副车架；弯曲预成形；内高压成形；数值模拟

DOI：10.15938/j.jhust.2018.02.023

中图分类号： TG394

文献标志码： A

文章编号： 1007-2683（2018）02-0129-05

Abstract：Winkles，ruptures and excessive thinning are the forming defects for curved hollow components.Taking a car front sub-frame as the research object， the hydroforming of sub-frame was studied by combing numerical simulation and forming experiment. The effect of bending parameters on the thinning during the bending process was studied. The influences of main process parameters on the forming quality were considered， such as the internal hydraulic pressure， the axial feeding and the loading path.Experiments of bending，preforming and hydroforming were carried out based on the optimum parameter of the simulation. The thickness distribution of typical section was measured and compared with the simulation result. It shows that the lateral of corner easily appears fracture and excessive thinning， and these forming defects could be avoided through optimizing the bending process parameters. The numerical simulation results have good conformity to experimental ones in the wall thickness distributions， their overall tendency of thickness distributions tend to be consistent in typical section， and the maximum difference of thickness between simulation and experiment results is 6%，which indicates that the proposed optimization method is feasible and can provide an effective guidance for the hydroforming of subframe.

Keywords：front sub-frame； bend preforming； hydroforming； numerical simulation

0 引 言

隨着生活质量的提升以及汽车的普及，能源危机、环境污染等问题日益凸显，全球各个国家对于汽车的排放量都做出了严格的规定，汽车轻量化也就成为了汽车研究关注的焦点[1-2]。目前，实现汽车的轻量化主要有两方面[3-5]：一方面是增加新型材料在汽车上的使用比例[6-7]；另一方面是改进汽车结构件的加工工艺，使用一次成形出来的管件代替拼焊的构架，从而减少装配量。由于增加新材料的使用量会增加汽车的成本，目前汽车厂商主要侧重于改进加工工艺[8-9]。……