筒形件液压拉深过程最优压边力的研究  

Optimal Blank Holding Force in Hydraulic Drawing Process of Cylindrical Cup

作　　者：赵升吨[1] 王骥[1] 尚春阳[1] 于德弘[1] 

机构地区：[1]西安交通大学,西安710049

出　　处：《应用力学学报》2004年第1期101-105,共5页Chinese Journal of Applied Mechanics

基　　金：高等学校全国优秀博士学位论文作者专项资金资助项目 ( 19993 0 )

摘　　要：结合筒形件液压拉深新装置的基本工作原理 ,提出了筒形件拉深法兰部分切向应变更为精确的简化计算公式 ,进一步获得了该法兰区域板料径向及切向应力的新的数学表达式。应用能量法重新建立了筒形件拉深时法兰区板料不起皱的最小压边力的数学表达式。明确指出液压拉深时拉深中的危险断面在板料凹模圆角区和筒壁区相交处 ,建立了相应的拉深力的计算公式 ,并获得了拉深破裂临界状态时极限拉深力及径向应力表达式。推导出了拉深破裂最大压边力的公式 ,指出实际拉深时最佳压边力应在防皱最小压边力和拉破最大压边力之间选取 ,同时根据该结果也能计算液体压力与最小拉深系数的关系。计算结果表明 ,该液压拉深方法可大幅度提高拉深变形程度 。The basic principle and advantages of a new hydraulic drawing mechanism for cylindrical cup are simply described and the necessity of analytical researching on optimal blank holding force(BHF)is pointed out in this paper. Firstly, a new reasonably simplified strain formula of flange of cylindrical cup is presented to approach the real stain by exponent x. Based on the strain formula, accurate expressions of tangential stress and radial stress of the cup flange are deduced. Secondly, the expression of minimum BHF avoiding flange wrinkle is rebuilt by using energy method, in which the surface integral method, more suitable for hydraulic drawing, is firstly used for calculating the energy consumed of BHF. According to analysis of the hydraulic drawing process, it is pointed out that the fractural section lies in the tangential area between rounded corner and straight wall of the die in hydraulic drawing. Finally, the maximum drawing force is acquired and the maximum BHF to avoid fracture is deduced, so the practical BHF curve should be chosen between minimum BHF avoiding wrinkle and maximum BHF to prevente from fracture, which depends on practical conditions. The relationship between hydraulic pressure and drawing ratio also can be drawn by numerical computation. The result of calculation shows that the new type of hydraulic drawing can greatly improve drawing ratio.

关 键 词：筒形件 液压拉深 压边力 能量法 金属加工 法兰变形区 应力分布 

分 类 号：TG386.32[金属学及工艺—金属压力加工]