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以Dynaform软件为分析平台构建有限元模型,利用数值模拟方法研究渐进成形圆孔翻边变形区厚度减薄现象。提出了最小厚度的理论计算公式,并验证了其可信性,并以此建立了翻边中部厚度减薄的判定标准。分析了翻边中部厚度减薄现象产生的原因并研究了通过多道次成形来避免减薄现象的可行性。结果表明:单道次渐进成形圆孔翻边K越小成形力越大,使翻边中部板料处于径向拉伸为主的双向受拉状态,从而导致了翻边中部厚度减薄;以减小成形力为准则设计多道次路径渐进成形圆孔翻边可有效的消除单道次成形时出现的翻边中部厚度减薄现象。
The Dynaform software was used as the analysis platform to construct the finite element model, and the numerical simulation method was used to study the thickness reduction of the deformed area of the flange of the ascending circular hole. The theoretical formula of the minimum thickness is put forward and its credibility is verified. Based on this, the criterion for determining the thickness of the flange is established. The reason of the thinning phenomenon in the middle of flanging was analyzed and the feasibility of avoiding thinning by multi-pass forming was also studied. The results show that the smaller the flange K is, the larger the forming force is, the more the billet in the middle of the flange is in the bidirectional tensile state, which leads to the reduction of the thickness in the middle of the flange. Reducing the Forming Force as a Criterion Designing multi-pass path progressive forming of circular hole flanging can effectively eliminate the phenomenon of thinning of the middle flange area during single pass forming.