汽车覆盖件回弹计算及补偿方法的研究

发布时间：2018-03-30 23:15

本文选题：板料成形　切入点：回弹　出处：《湖南大学》2016年硕士论文

【摘要】：回弹是冲压成形工艺的主要缺陷之一,也是影响冲压件尺寸精度的主要因素。随着高强度钢板等新冲压板材的广泛应用以及冲压件形状的日益复杂,回弹问题变得越来越突出。传统的解决方法主要基于经验积累,花费了大量的时间和人力,随着板料成形数值模拟技术的出现和发展,利用有限元数值模拟技术解决回弹问题已经成为研究的主流。因此本文基于有限元数值模拟技术对回弹问题进行了研究,本文主要工作如下:1.针对差厚拼焊板相对单一板料的不同之处,分析成形数值模拟对回弹预测的影响,并提出差厚拼焊板的有限元精确建模方法。该方法在差厚拼焊板的板料建模过程中准确设置不同厚度板料的中性层位置,然后对模具网格设置模具阶梯,并依靠焊缝线的位置和冲压成形过程中焊缝线漂移距离确定模具阶梯曲线的位置,从而得到精确的有限元仿真模型用于差厚拼焊板的冲压成形数值模拟计算。通过一算例证明精确建模方法能够提高成形及回弹的预测精度,可以用于差厚拼焊板的有限元数值模拟计算。2.对汽车覆盖件的迭代回弹补偿过程进行了研究,考虑到回弹补偿每次迭代都需要利用上一次板料的补偿结果构建新的模具网格,本文提出一种新的模具网格重构方法用于回弹补偿的迭代计算。该方法基于有限元的冲压数值模拟方法,利用板料网格与模具网格的对应关系将板料网格的补偿量赋予模具网格,实现模具网格的补偿。具体方法是:通过数值模拟软件模拟回弹工序得到零件的回弹计算结果,利用节点反向映射的方法补偿零件的回弹误差,将修边工序修剪掉的工艺补充网格做出调整,然后分别拼接到修边后和补偿后的零件网格上得到相应的拼接网格,将模具网格节点映射到成形的拼接网格,再在补偿的拼接网格上生成补偿的映射点,反向映射补偿的映射点即可得到补偿的模具网格节点,从而得到补偿模具网格。3.以某轿车前舱内横梁模型为例,对其进行冲压数值模拟仿真,利用节点反向映射的补偿方法迭代补偿回弹,并利用本文提出的回弹迭代计算中完整工具网格构建的方法构建工具网格,分析验证该方法的可行性。
[Abstract]:Springback is one of the main defects in stamping process, and it is also the main factor that affects the dimensional accuracy of stamping parts. With the wide application of new stamping plates such as high strength steel plates and the increasing complexity of stamping parts' shape, The springback problem becomes more and more prominent. The traditional solution is mainly based on the accumulation of experience, and it takes a lot of time and manpower. With the emergence and development of numerical simulation technology of sheet metal forming, Using finite element numerical simulation technology to solve springback problem has become the mainstream of research. Therefore, based on finite element numerical simulation technology, the springback problem is studied in this paper. The main work of this paper is as follows: 1. In view of the difference between differential thickness TWW plate and single sheet metal, the effect of numerical simulation on springback prediction is analyzed. The finite element precise modeling method of differential thickness TWW plate is proposed, which sets the neutral layer position of different thickness TWW plate accurately in the course of the plate modeling process, and then sets the mould ladder to the die mesh. The position of step curve of die is determined by the position of weld line and the drift distance of weld line during stamping forming. Thus the accurate finite element simulation model is obtained for the numerical simulation of the stamping forming of the differential thickness TWW plate. An example is given to prove that the accurate modeling method can improve the prediction accuracy of the forming and springback. This paper studies the iterative springback compensation process of automobile panels, considering that each iteration of springback compensation needs to use the compensation results of the last sheet metal to construct a new die mesh. In this paper, a new mesh reconstruction method is proposed for the iterative calculation of springback compensation, which is based on the finite element method of stamping numerical simulation. The compensation amount of sheet metal mesh is given to die mesh by using the corresponding relation between sheet metal mesh and die mesh, and the compensation of die mesh is realized. The concrete method is: the springback calculation result of parts is obtained by simulating springback process by numerical simulation software. Using the method of node reverse mapping to compensate the springback error of the parts, the trimming process trimmed process supplementary mesh is adjusted, and then spliced to the trimmed and compensated parts mesh respectively to obtain the corresponding splicing mesh. The die mesh node is mapped to the formed splicing mesh, and then the compensated mapping point is generated on the compensated splicing grid, and the compensated die mesh node can be obtained by reverse mapping the compensated mapping point. Thus, the compensation die mesh. 3. Taking the model of the cross beam in the front cabin of a car as an example, the stamping numerical simulation is carried out, and the compensation method of node reverse mapping is used to compensate the springback iteratively. The method proposed in this paper is used to construct the tool grid, and the feasibility of the method is analyzed.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U466;TG386

【相似文献】