汽车前托架成形过程研究

发布时间：2018-09-08 07:11

【摘要】：人们利用板料成形数值模拟技术用于模拟板料冲压成形过程,不但可以预测成形缺陷,还可以借助模拟来优化工艺参数、分析成形过程、评估模具设计方案。从而缩短了模具开发周期,提高了板料零件成形质量,降低了生产成本。在板料成形数值模拟领域内,前人已进行了许多研究工作,但少有涉及对具体某一复杂成形件的成形优化过程的分析讨论。而在实际工程中,对于一部分成形难度大的零件,通过对简单的工艺参数进行调试再试模往往不能得到合格零件。某汽车前托架零件三维空间型面复杂,具有一定成形难度。针对此零件的冲压成形,本文制定了前托架零件的成形工艺,分析了其拉延成形数值模拟的具体前处理设置,其中重点分析了工具体与板料的网格划分。在试算后,分析了成形结果与网格划分的合理性。试算结果显示板料同时存在破裂与起皱缺陷,然后分别对压边力、摩擦系数、冲压速度做了三组基于单因素变化的试算,探究了它们对成形结果的影响。结果显示压边力与摩擦系数的不同都对成形结果有较大影响。随着压边力与摩擦系数的增加,破裂单元数目递增,起皱单元数目递减,而成形速度几乎不影响成形结果。发现板料在各种工艺参数条件下都同时存在破裂与起皱缺陷后,结合板料破裂危险区的形变分析,对模面进行了合理修改。并在此基础上,进一步优化压边力工艺参数。采用优化后的工艺参数和模面形状进行实际试冲调试并得到了合格的成形零件。同时,实际板料轮廓收料情况与有限元计算得到的结果相符,验证了优化后的工艺参数和模面形状的合理性。
[Abstract]:The numerical simulation technology of sheet metal forming can not only predict the forming defects, but also optimize the process parameters, analyze the forming process and evaluate the design scheme of the die by using the numerical simulation technology of sheet metal forming. Thus, the die development cycle is shortened, the forming quality of sheet metal parts is improved, and the production cost is reduced. In the field of numerical simulation of sheet metal forming, many researches have been done, but there is little discussion about the optimization process of a complex forming part. But in the actual engineering, for some parts which are difficult to form, the qualified parts can not be obtained by debugging and retrying the simple process parameters. The three-dimensional profile of the front bracket part of an automobile is complex and difficult to form. For the stamping forming of this part, the forming process of the front bracket part is established, and the pre-processing setting of the numerical simulation of the drawing forming is analyzed, and the mesh division between the tool body and the sheet metal is emphatically analyzed. After trial calculation, the rationality of forming result and mesh division is analyzed. The results show that the sheet metal has fracture and wrinkle defects at the same time. Then three groups of experiments based on the change of single factor are made for the blank holder force, friction coefficient and stamping speed respectively, and the influence of them on the forming result is explored. The results show that the difference of the blank holder force and friction coefficient has a great influence on the forming results. With the increase of the blank holder force and friction coefficient, the number of fracture elements increases and the number of wrinkled elements decreases, while the forming speed has little effect on the forming results. It is found that the defects of rupture and wrinkle exist simultaneously under various technological parameters, and the die surface is modified reasonably by combining with the deformation analysis of the dangerous area of sheet metal rupture. On this basis, the process parameters of the blank holder force are further optimized. The optimized process parameters and die surface shape were used to test and debug and qualified forming parts were obtained. At the same time, the results obtained by the finite element method are in agreement with the results obtained by the finite element method, which verifies the rationality of the optimized process parameters and the shape of the die surface.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG386

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