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基于修正的Drucker-Prager Cap模型建立弹塑性本构模型,采用三维有限元模型对粉末压制过程及压制脱模后压坯的残余应力进行仿真分析。利用几个典型的力学性能测试实验确定粉末Distaloy AE的模型参数。模型通过用户子程序USDFLD实现,对粉末Distaloy AE的模压过程及脱模后压坯(d20 mm×5 mm)的残余应力进行预测分析。有限元分析结果与模压实验和X衍射实验结果基本吻合,验证了模型的有效性。结果表明,压坯的侧表面存在一层显著的残余压应力,而压坯上表面和下表面的残余应力值则很小。
Based on the modified Drucker-Prager Cap model, an elasto-plastic constitutive model was established. The three-dimensional finite element model was used to simulate the powder compacting process and the residual stress of compact after pressing and demolding. Several typical mechanical properties tests were used to determine the model parameters of Distaloy AE powder. The model was realized through the user subroutine USDFLD. The molding process of Distaloy AE powder and the residual stress of the compact (d20 mm × 5 mm) after demolding were predicted and analyzed. The results of finite element analysis are in good agreement with the results of compression test and X-ray diffraction. The validity of the model is verified. The results show that there is a significant residual compressive stress on the side surface of the green compact while the residual stress on the upper and lower surfaces of the green compact is very small.