摘要
应用上限法建立了由矩形毛坯正挤压矩形截面工件的等挤压比流动模型 ,推导出了三次多项式表示的流线方程 ,给出了变形区的动可容速度场、应变速率场及上限功率的表达式 ,获得了挤压力的上限数值解 ;分析了变形程度、工件截面形状等参数对挤压力的影响 ,并获得了相对挤压应力与截面形状系数之间的近似关系式。研究证明采用流线速度场进行上限分析比其他方法更符合实际情况 ,根据流线设计的凹模优于常规凹模 ,如平底模。
The upper bound method is used to build the extrusion flow model of rectangular section from rectangular blanks,i.e. the model of indentical extrusion ratio.The flow equation is established with 3rd order polynome. The kinematically admissible velocity field , the strain rate fieldand the deformation power are formulated. The numerical solution of pressure is obtained. The effects of reduction of area and the shape of section on the extrusion force are analyzed. And the relational expression of relative stress to the shape of section is suggested. The study indicated that the upper bound analysis with streamline velocity field in deformation process can offer the results much better than that got with other approach and the die contour designed by this is superior to common one,such assquare die.
出处
《金属成形工艺》
2002年第3期1-4,30,共5页
Metal Forming Technology
基金
江苏省"青蓝工程"跨世纪学术带头人培养人选基金
关键词
矩形截面毛坯
挤压
矩形工件
上限法
流线方程
流线模
extrusion
rectangular seection
flow equation
streamline die
the upper bound method
