AN UPPER BOUND SOLUTION FOR THE FORCE OF COMBINED BACKWARD-FORWARD EXTRUSION

A rigid-triangle velocity field for combined backward-forwardextrusion based on the experiments and the slip-line field isproposed in this paper.The flow separation point in the ri-gid-triangle velocity field is defined in accordance with theslip-line theory.A formula of minimum upper bound solutionfor the punch pressure of the combined extrusion is derived.The values from this formula are compared with those from theslip-line solution and with experimental results.The formulaof upper bound solution can be used in practice.     

复合挤压力的上限解

本文根据实验和滑移线场拟定复合挤压时的速度不连续刚性三角形,由此得出复合挤压时凸模单位压力的最小上限解的解析式,将此式解值和实测值进行比较,表明上限值可供实际使用.