中文摘要：

针对传统有限元法进行冷挤压成形模拟时出现的网格畸变问题,开展基于物质点法冷挤压成形过程的数值模拟研究。通过建立冷挤压成形过程物质点法仿真模型和编制程序,分别对锥模和平模两种情况下的冷挤压成形过程进行模拟研究,得到其变形规律,并与实验和有限元方法计算结果进行比较。通过锥模冷挤压成形过程的数值模拟,得到不同挤压量下挤压件形状和挤压件高度值,与实验结果吻合较好,最大误差为0.52%。通过平模冷挤压成形过程的数值模拟,得到不同挤压量下挤压件的变形规律,当压下量较大时,物质点法能较好地实现冷挤压成形过程的数值模拟,而有限元法出现了网格畸变。研究结果表明,物质点法模拟冷挤压成形过程是可行的,能够有效地消除网格畸变。

英文摘要：

For the problem of mesh distortion when the finite element method（ FEM） was applied in the simulation of extrusion forming,a novel material point method（ MPM） was introduced. The extrusion forming processes under taper die and flat die were simulated by establishing models of material point and program written in the extrusion forming,and the deformation rules were obtained. Then,results of experiment and calculation were verified. Furthermore,the shape and height of extrusion part were obtained by simulating the cold extrusion forming with taper die. The results of simulation are in good agreement with those of experiment,and the maximum error is 0. 52%.The deformation rule of extrusion part was obtained by simulating the cold extrusion forming with flat die. When the reduction is larger,the cold extrusion forming process is simulated successfully by MPM,but a mesh distortion appears by FEM. The results show that the MPM is feasible and effective for simulating the cold extrusion forming process and the mesh distortion can be effectively eliminated.