目的 对比研究力-位移分控多点弯曲成形的受力和变形特点,揭示力-位移分控多点成形技术改善成形质量的机理。方法 首先设计制造出采用力-位移分控多点成形原理成形的实验装置,并进行圆柱面的实际成形,比较不同成形模式下所获得成形制件的差异,然后采用理论分析和数值模拟等手段,分析对比不同成形模式的受力与变形条件,探讨不同成形模式下的变形特点与规律。结果 从理论上给出了力-位移分控多点成形能有效减小回弹、消除“直边效应”的力学原理,指出了力-位移分控多点成形技术减小回弹的根本原因在于法向约束力的作用,且回弹减小量与法向约束力的大小成正比,并通过数值模拟,从应力和应变分布、支反力变化等方面予以了验证。结论 力-位移分控多点成形从本质上改变了板材的受力和变形条件,能有效提升成形质量。
The paper aims to make a comparative study on stress and deformation characteristics of multi-point forming with individually controlled force-displacement (MPF-ICFD) and reveal the mechanism of the improvement of forming quality in MPF-ICFD. The experimental device of MPF-ICFD was designed and manufactured firstly and the actual forming of cylinder surface was conducted. The differences between the forming parts under different forming modes were compared and then the stress and deformation conditions were analyzed and compared respectively by means of theoretical analysis and numerical si- mulation. In addition, the deformation characteristics and regulars of different forming modes were discussed so as to reveal the mechanism of the improvement of forming quality in MPF-ICFD. The mechanics principles of effective decrease of springback and elimination of the "straight edge effect" in MPF-ICFD were given in theory respectively, which pointed out that the funda- mental reason for the decrease of springback in MPF-ICFD was the effect of the normal constrained force and that the amount of springback was proportional to the magnitude of the normal constrained force. The results were verified in aspects of the stress and strain distribution as well as the variation of reaction force by numerical simulation. MPF-ICFD are changes the stress and deformation condition of the sheet essentially and can improve the forming quality effectively.