厚向异性值r及应变硬化指数n对板料拉深成形性能的影响

AN ANALYSIS OF THE INFLUENCE OF NORMAL ANISOTROPY r AND STRAIN HARDENING EXPONENT n ON THE DRAWABILITY OF SHEET METALS

基于R·Hill的各向异性材料理论及W·Panknin的关于拉深应力的计算方程,通过理论分析研究了n,r值对拉深成形时杯形件简壁的屈服和破裂的影响。实验表明,n值对极限拉深率几乎无影响,在n,r值对材料破裂的影响方面,实验结果同理论分析吻合得相当好。本又对拉深成形的理论分析解释了r,n值之间的相互关系,因此,更好地理解和预测板料的拉深性能是可能的。

The influence of n and r values on the yielding and failure of the cup wall in deep drawing is investigated through a theoretical analysis. The analysis is based on R. Hills theory on anisotropic materials and on W. Panknin' s equations concerning the calculation of the drawing stresses. Experimental work confirms that n has only little influence on the limiting drawing ratio (LDR). The expermental results are very much in accordance with the theoretical analysis as far as the influence of n and r on the failure of the material is concerned. The analytical treatment of deep drawing achieved in this theoretical study explains the interaction between r and n values. It is thereby, possible to better understand and predict the deep drawing behavior of sheet metals.