变薄拉延过程的上限模型及其应用

根据上限原理建立了一种变薄拉延过程的上限模型，。其中包含两个准独立参数，可以通过最优化，获得变薄拉延过程的最佳上限解．同时研究了主要工艺条件对变薄拉延力和筒体拉应力影响的规律，并对变薄拉延的最佳半锥角和极限变薄拉延系数进行了深入探讨．所得到的结果对设计变薄拉延用模具和制定合理工艺参数有指导意义．

An Upper-Bound Model for Ironing Process and its Application

An upper-bound model with two pseudo-independent parameters is formulated for ironing process.The optimal solution of the ironing process can be obtained through optimization of the proposed model with respect to the two pseudo-independent parameters. Moreover, the proposed model is also sultuble for work-hardening materials. The analytical results have been verified by experbocntal results.The ironing force. temsile stress, semicone angle and limit ironing coefficient for ironing process can ie conveniently determined by using the curves presented in Figs. 2,3 and 4.The analytical results indicate that the boaing force and tenisle stress within the workpiece increase significantly with decreaseing ironing coefficient. The ratio of inside radius to outside radius (R1/R0) has remarkable effect on the ironing force. The tensile stress within the workpiece, however, is almost independent of the values of (R1/R0).The value of the optimal semicone angle is strongly dependent on lubrication condition and ironing coefficient. The friction factors among workpiece, dies aDd mandrel arc the main factors affecting the limit ironing coefficient. The achievements of this study may serve as the guide to designing the ironing die and determining the optimal process variables.