型材三维拉弯成形数值模拟及回弹特性研究

Research on numerical simulation and springback characteristic for 3D stretch-bending parts

轻量化薄壁三维弯曲结构件广泛应用于大型高端装备制造业当中,然而,受材料性能及复杂目标零件形状的约束,三维弯曲成形件的回弹问题尤为突出。为此,通过对柔性多点三维拉弯成形工艺原理的抽象与合理简化,建立了矩形截面型材的成形过程及回弹变形的有限元仿真模型,基于开发的柔性多点成形装备,利用实验验证了上述模型的有效性。随后,对不同截面形状（矩形、T形、L形）铝型材开展回弹特性研究。回弹预测水平和垂直方向最大绝对误差为0.52和0.36 mm,最大相对误差为14.77%,仿真结果与实验结果基本吻合,且回弹变形的变化趋势一致。在相同材料和调形参数条件下,矩形、T形、L形截面成形件轮廓度误差分别为1.72%,0.84%,0.62%,依次递减,而失去对称几何结构的截面型材截面变形程度依次递增。以上研究成果为实现任意截面形状三维拉弯制件的精确成形奠定了基础。

The finite element model for forming process of the rectangle cross-section profile and the springback deformation was established by the abstraction and reasonable simplification of the flexible multi-point 3 D stretch-bending process principle,and the effectiveness of the simulation model was verified by experiment based on the flexible multi-point forming equipment. Then,the springback features for the 3 D stretch-bending parts were studied with different cross-section shapes including rectangle section,T section,and L section. The result shows that the maximum absolute error of springback prediction is 0. 52 mm in the horizontal direction and 0. 36 mm in the vertical direction as well as the maximum relative error is 14. 77%. Thus,the simulation results and springback deformation trend are in good agreement with the experiment results. Under the same material and adjustment parameters condition,the contour error decreases from rectangle profile（ 1. 72%）,T profile（ 0. 84%） to L profile（ 0. 62%） gradually,while the shape deformation of the cross-section without symmetrical geometry increases gradually.