铝合金板滚压包边仿真分析建模关键技术

Key techniques in the numerical simulation and modeling for roller hemming of aluminum alloy sheet

滚压包边是一种复杂的多工步单点连续加载工艺过程,在产品早期开发阶段就需要对滚压包边工艺进行可行性设计,依赖经验和试错的方法已无法满足滚压包边技术的要求。从单元模型、加载方法等方面深入研究滚压包边仿真分析建模关键技术,以指导产品和工艺设计。研究表明:采用最小尺寸为0.5 mm的壳单元,既能提高计算效率,也能保证数值模拟精度;考虑到计算的效率,数值模拟研究均采用了厚向7个积分点的4节点减积分壳单元S4R;可以采用摩擦系数为0的滚轮滑动模拟滚动;对零件轮廓尺寸变动量进行数值模拟时,可以不考虑翻边变形所产生的材料强化,模拟材料断裂时不能忽略翻边所产生的预应变。

Roller hemming is a complex process with single point continuous loading by multi-steps. The design of feasibility in the process should be completed at the early stage of the development. However, experiences or trial and error method can not meet the re- quirements of roller hemming process at current. In order to manage production and design processes, the key techniques in numerical simulation and modeling for roller hemming of aluminum alloy sheet were studied, which included element type, loading method and so on. The investigation shows that the computing efficiency and accuracy of numerical simulation can be assured by the minimum shell ele- ment size ofO. 5 mm. For computing efficiency, the shell element S4R with the reduced integration four-node shell element of seven thick- ness integration points was adopted in simulation. Moreover, rolling movement simulation can be replaced by sliding with friction coeffi- cient of zero. Furthermore, the hardening effect induced by flanging process can be neglected in the simulation of variants of contour size of parts, and pre-strain should not be ignored when the fracture of material is simulated.