LY12CZ铝合金轴对称拉伸过程的计算模拟

Computational Simulation of Axisymmetric Tension Testing of Aluminium Alloy LY12CZ

用大应变弹塑性有限元程序对LY12CZ铝合金材料制成的轴对称光滑及切口试样在单调载荷作用下的变形场、应力场作了计算模拟 ,给出了在不同加载水平下 ,试样最小横截面上的应力场和变形场。计算结果表明 :最小横截面上 ,光滑试样近似处于单向拉伸应力状态 ,且应力、应变均匀分布 ;而切口试样的轴向应变不再保持均匀一致 ;周向应变和径向应变不再相等也不再均匀分布。此时 ,Bridgeman公式所赖以建立的基本假设有较大误差。计算中采用临界空穴扩张比 (VGC)准则来预测起裂 ,所得结果与试验结果较为吻合 ,表明切口试样从心部起裂 ,可将 (VGC)发展过程用于预测切口试样的起裂位置。

The computational simulation of the monotonic behavior of Aluminum alloy LY12CZ is taken, using large deformation elastic-plastic limited element. On the least cross section, the stress and strain of the smooth specimens is uniform, while the radial strain isn't equal to the circumferential strain and the distribution of the radial strain, the circumferential strain and the axis strain of the notched specimens isn't uniform, the Bridgeman equation isn't suitable for this case. The V GC criterion was applied to predict the crack initiation location, the simulated results show that the crack is generated in the center of the notched specimens, which agrees very well with the experimental results. It was identified that the process of V GC could be used to predict the crack initiation location of the notched specimens.