镁合金板料温冲压成形数值模拟技术

用板料成形的方法对变形镁合金进行加工可以制造更薄更轻的零件,符合轻质化的发展趋势.利用有限元数值模拟的方法可以对实际的冲压过程进行模拟,达到改进工艺与模具的目的.对于板料加热状态下的数值模拟,为了使结果准确,最重要的就是要建立正确的材料本构关系模型,这一材料模型需给出应变、应变率、应力与温度之间的关系.在经典的塑性成型计算中,材料模型包含两方面的内容:①初始屈服表面的确定,②流动法则和加工硬化模型的建立.总结了经典屈服模型和材料本构关系模型以及国内外学者在经典理论基础上建立起来的镁合金材料模型;探讨了板料成形有限元数值模拟技术以及目前常用的模拟软件;并在此基础上综述了镁合金冲压变形的热-机耦合的数值模拟的研究进展.

Numerical Simulation Technology of the Warm Pressing of Magnesium Alloy Sheet

Sheet forming is an appropriate method to produce lighter and thinner magnesium alloy parts. Numerical simulation technique can be used for simulating the practical pressing process, and improving the die designing and machining technologies. The most important task in numerical simulation of hot pressing is to constitute an accurate constitution model of the material, in which the relationships between the stress and the temperature, strain rate, and strain should be explicit. In the classical plasticity calculation, a material model includes the constitution of yield model and work hardening flow stress model. In the paper, the classical yield stress, flow stress and the newest research results of the magnesium alloy constitution models are summarized, the status of the thermal-mechanical coupling numerical simulation of the magnesium alloy sheet warm pressing and the corresponding softwares in common use are reviewed.