板材塑性成形理论和技术在汽车工业中的应用及其发展趋势

General trends of technology and plasticity related issues on sheet metal forming processes in automotive production

依靠冲压工艺成形的汽车外蒙皮件及框架结构件在汽车工业生产中扮演着一个重要的角色 ,并在很大程度上决定着一种新车型能否最终赢得市场。所以 ,对其相关的技术必须给予高度的重视。只有依托高水平的技术支持 ,才能获得高质量的产品。涉及冲压工艺生产的相关技术包括 :板材塑性力学 ,冲压工艺过程的有限元分析(FEA) ,具体的成形工艺设计等。其中 ,塑性力学 ,包含其最基本的屈服准则 ,本构关系 ,大变形过程中其各向异性板材方向特性的再定义 ,以及适合于不同冲压工艺的成形极限图 (FLD)等。而对于有限元模拟 ,其关键的实用技术 ,是了解不同应用程序的使用特点及局限性 ,并找到相关的控制措施。涉及具体的成形工艺 ,则必须以可成形性及经济性为准则进行相关的压边工序及辅助部分的设计 ,并对成形道次进行综合分析 ,以获得经济。

Panels and frames of vehicles produced by the stamping processes play a major role in the automotive production,in a certain degree,which will result in the marketing of a new vehicle model to be going successful or not.Thus,technologies related to this kind of work must be paid more attention.High quality of these parts obtained relies on the technological developments involving the basic plasticity,FEA simulation and processing technology,In the scope of basic plasticity,which deals with the yield criteria,constitutive relations of stress and strain,the reorientation behaviors caused during a large deformation on an anisotropic strain\|hardening material,and the forming limit dependence on loading history.With related to the FEA simulation work,the main works are finding out the difference and limitation with respect to each program.Effective control methods regarding to the dynamic effect while using dynamic code,and improving constringency by using implicit code,are all the important research projects.For the processing related issues,higher quality and lower weight requirements on the vehicles push binder design and die development to be going up a big progress,in which how to attach a helpful addendum on the associated tooling and how to decide the forming type,should be also the worth study in sheet metal forming field.