以某典型铝合金复杂曲面薄壁罩体为研究对象,采用数值模拟与工艺试验相结合的方法分析了凸模初始反胀位置与液室压力对成形失稳的影响规律,优化了成形工艺参数。结果表明,当凸模初始反胀位置低于凹模型面时,凸模进入凹模时悬空区板料没有液室压力的作用,悬空区板料处于一拉一压的应力状态,悬空区容易起皱;当凸模初始反胀位置在凹模型面上方时,凸模进入凹模时悬空区板料已经受到液室压力的作用,处于双向拉应力状态,因此可以抑制悬空区起皱;当液室压力较高时,悬空区板料承受较大的拉应力容易破裂。合理控制凸模初始反胀位置与液室压力可以消除悬空区起皱与破裂。 Taking a typical aluminum alloy complex curved thin-walled shell body as the research object, the influence of the initial anti-expansion position of the male die and the pressure of the liquid chamber on the forming instability was analyzed by means of numerical simulation and process test, and the forming process parameters . The results show that when the initial anti-expansion position of the punch is lower than that of the concave surface of the die, the punch in the hollow die does not have the pressure of the liquid chamber when the punch enters the die. Wrinkling; when the initial anti-expansion punch position above the concave surface of the mold when the punch into the die when the vacancy sheet has been under the pressure of the liquid chamber in the biaxial tensile stress state, it can suppress the dangling area crease; when Liquid chamber pressure is high, the vacant area to withstand greater tensile stress plate easily rupture. Reasonable control of the initial position of anti-bulging punch and liquid chamber pressure can eliminate dangling wrinkling and rupture.