任意形状坯料反挤压成形内圆筒的上限单元技术的改善分析  

Modified analysis of backward extrusion of internally circular shaped tubes from arbitrarily shaped billets by upper bound elemental technique

作　　者：罗凯文[1] 骆先梅[1] 

机构地区：[1]湘潭大学

出　　处：《锻压技术》1998年第4期3-8,共6页Forging & Stamping Technology

基　　金：国家自然科学基金

摘　　要：提出了对任意形状坯料的反挤压成形内圆筒的运动许可速度场改善。在以前各种著作中出现的速度场不满足在模具和材料接触面的法线速度必须为零的条件而且忽略了冲头下面的材料旋转。通过本文，对前者进行修正，对后者以一种新的速度场进行改进。被提出的速度场中，规则多边形的上限挤压载荷和平均挤压高度决定于被选择的参数。文中挤压载荷的理论计算值比以前文献中出现的低，且更接近实验结果。当采用本文提出的速度场时，平均挤压高度与网格变形的理论模拟计算与实际情况相吻合。A modified kinematically admissible velocity field for the backward extrusion of internally circular shaped tubes from arbitrarily shaped billets is proposed. The original velocity fields appearing in the liberature did not satisfy the condition that the normal velocity on the die and material interface must be zero, and material rotation under the punch was neglected. Therefore, in this work the fomer is corrected and the latter is improved by a new velocity field. From the proposed velocity field, the upper bound extrusion load and average extruded height for regular polygonal shaped billets are determined with respect of the chosen parameters. The theorelical predictions of extrusion load are lower and closer to the experimental results than those in the previous literature. The average extruded height and the grid distortion of theory and experiment agree well when using the proposed velocity field.

关 键 词：上限单元 内圆筒 反挤压 挤压 速度场 挤压载荷 

分 类 号：TG37[金属学及工艺—金属压力加工]