圓柱扭轉鍛造成形之研究

Study on the Twist Forging Forming of Cylinder

鄒國益(Gou-Yi Tzou) ； 成清吉(Ching-Jyi Chen) ； 黃敏郎(Ming-Nan Huang)

《鍛造》 16卷2期 (2007/07) Pp. 5-12

https://doi.org/10.29791/Forging.200707.0002

摘要

本研究是以切片法和上界限法來探討圓柱扭轉鍛造成形之塑性行為。兩種分析方法均假設圓柱與旋轉鍛壓模具間的摩擦為定剪摩擦(τ=mk)。以上界限法建構扭轉鍛造成形之三維動可容速度場，進而求得所需之上界限能量消耗總功率，再利用能量最小化方法求得最佳可變參數。旋轉鍛壓上下模具的旋向是相反的，所以圓柱是在扭轉的情況之下，同時壓縮而成形。故作用在圓柱的摩擦剪應力(τ)並非作用在圓柱的半徑方向上，而是作用於與離圓柱半徑方向角度α之方向，依據徑向與周向速度之關係，在解析過程之中可求得α角的大小。利用上界限法與切片法有效地探討摩擦因子、圓柱半徑高度比、壓下率及旋轉角速度等對於扭轉鍛造成形特性之影響。同時在自行設計之旋轉壓縮成形原型機上進行實驗，相互比較並驗證兩種解析模式的適用性。

關鍵字

扭轉鍛造成形 ； 定剪摩擦 ； 上界限法 ； 切片法

並列摘要

In this study, the slab method and upper bound method are proposed to investigate the plastic between under the twist forging forming of cylinder. Both upper bound method and slab method assume the friction between the cylinder and the dies as constant shear friction (τ=mk). The total power rate of the energy consumption with a 3D kinematical velocity field based on the upper bound method is constructed, and an optimum variable parameter is obtained by using the energy minimization method. The upper and lower dies are rotated in different directions, so the cylinder is compressed with the twist circumstance, and the frictional shear stresses (τ) are not acted in the radial direction. The stresses (τ) are acted in an arbitrary direction at angleα from the radial direction relations to the r-axis. According to the velocity relations between radial direction and circumferential direction, angle u can be determined. Using the upper bound method and the slab method, the effects of frictional factor, aspect ratio, height reduction, and angular velocity etc on the twist compression forming characteristics, are explored effectively. The feasibility of both models can be verified by comparisons of two models and the experiment performed in the rotating compression prototype machine designed by ourselves.

並列關鍵字

Twist forging forming ； Constant shear friction ； Upper bound method ； Slab method