车用铝合金板材回弹规律研究

Experimental and numerical investigation on springback of automotive aluminum alloy sheet

摘要:

在车用铝合金材料的成形加工过程中,回弹是主要的成形缺陷之一并且较难控制。本文对车用6061铝合金板材进行了室温拉伸试验获得其应力-应变曲线并建立改进的Johnson-Cook本构模型。该模型被应用于V形弯曲试验的有限元仿真中,研究不同各向异性屈服准则对板料回弹预测精度的影响,仿真结果表明应用YLD2000-2d屈服准则时其预测精度较高,同时也验证了该模型用于回弹分析的有效性。进一步探究不同因素如变形程度,冲压速度,摩擦条件,压边力等对铝合金板材回弹行为的影响规律,并应用于铝合金发罩内板的冲压成形过程,能够有效减小工件的回弹。

Abstract:

In the forming process of automotive aluminum alloy, springback is one of the main defects and difficult to be controlled. In this study, stress-strain curves of automotive aluminum alloy 6061 are obtained through tensile tests at room temperature and the constitutive model is established based on a modified Johnson-Cook equation. The model is used in finite element simulation of V-bending tests to investigate the effect of different anisotropic yield criterions on accuracy of springback prediction. Experimental and simulation results indicate that the prediction results are more accurate when YLD2000-2d yield criterion is applied and the efficacy of the model in sprignback analysis is verified. Furthermore, the effect of several different factors on springback behavior of aluminum alloy sheet was investigated, including deformation degree, drawing velocity, friction condition and blank holding force. The experimental and numerical investigation is applied in stamping forming process of aluminum alloy inner panel of engine cover and the springback is reduced effectively.