型材拉弯数值模拟夹钳边界条件的一种等效模型

An equivalent model of jaw's boundary condition in numerical simulation of stretch bending for extrusions

拉弯是一种重要的型材弯曲工艺,被广泛应用于汽车和飞机制造业。有效应用该工艺必须了解不同工艺参数如何影响工艺过程和零件最终形状。当前数值模拟是研究这些问题的一种有效手段。然而准确模拟成形过程的前提是准确描述毛料的边界条件。张臂式拉弯夹钳力矩边界条件复杂,在数值模拟中处理困难,为此该文提出了一种位移加载等效模型。利用该模型对矩形中空截面铝合金型材张臂式拉弯过程进行了模拟和试验验证。切向应变、截面畸变和回弹模拟结果与试验结果基本吻合,说明上述夹钳等效模型可行,为后续工艺参数优化提供了基础。

Stretch bending is an important bending process of extrusion and widely used in automotive and aircraft industries. Effective application of this process demands sufficient knowledge of how different parameters influence the process and the final shape of the product. Numerical simulation is an effective approach of investigating these issues presently. However, an accurate description of blank＇s boundary condition is needed in order to simulate forming process accurately. An equivalent model is proposed to treat jaw＇s boundary condition in stretch bending process and stretch bending of rectangular hollow section aluminum extrusion is simulated by using this model. It is found that the results of tangential strain, cross-section distortion and springback agree with experiment in reasonable accuracy. So it is shown that the proposed equivalent model is feasible and lays the groundwork for future optimization of process parameters.