【摘要】 本文基于胀形过程中各阶段坯料内表面为球面的一部分以及将坯料视为由若干近似梯形截面的环所组成的假定,利用塑性理论以及平衡条件,提出了一种考虑加工硬化的胀形过程的数值计算方法。这种方法较有关文献资料建议的方法简单,节约机时,而且计算结果与实验结果的一致性令人满意。更多还原

【Abstract】 On many occasions bulging process is often the precursor of sheet metalforming processes.In a sense bulging is the key to the processes.Therefore,bulging process has been investigated extensively and thoroughly[1] [2] [3] [4] .Different methods have been proposed for simulation and analysis of thisprocess[1] [2] .In the method presented in[1] it is assumed that the curva-ture radii of inner surface vary with coordinates.The above assumption hasmade the method tedious and time-consuming.In order to take thickness changealong the bulge profile into consideration the blank is considered as beingmade of several rings with uniform thickness[1] [2] .Obviously it dose nottally with the actual situation.It is necessary for the previous methods toassume that the blank has already been subjected to a small amount of defor-mation.The method proposed by the authors is simpler and more efficient thanprevious methods.This method is based on following assumptions:the innersurface of bulge profile is a part of spherical sureface during the process andthe blank consists of several rings with approximative trapezoid section.Incorporating Levy-Von Mises stress-strain relatiocship and equilibrium con-ditions,six basic equations are derived.By using these equations,the bulgeprofile at any moment during the process,stress and strain filed in the blank,and the influence of process variables on the polar thickness strain,ect.canbe predicted.It should be pointed out that it is possible for the user of theproposed method to analyse the bulging process from the original state of theblank,thus improving accuracy of numerical analysis.In order to verify the proposed method it has been applied to analysis ofbulging of annealed copper sheet.Based on calculated results,the change inbulge profile during the process,stress and strain distribution in the blank atdifferent hydrostatic pressure,and relationship between polar thickness strainand hydrostatic pressure are presented.A comparison of the obtained resultswith calculated results of[1] and the experimental data of other sources[4] ,shows a satisfactory agreement between them,更多还原