Plastic bending of adhesively bonded dissimilar sheet metals using temperature and rate-dependent highly ductile

本文提出了一种与传统的胶接工艺完全不同的金属薄板塑性成形新工艺，即将两块相同材料的平板胶接在一起，然后压制成形。在该技术中，抑制大的横向剪切变形发生在粘接层弯曲过程中是至关重要的，因为它会导致弯曲板的几何缺陷（所谓的鸥翼弯曲）。分析考虑为二维平面应变问题。利用Marc 2005的Table函数对粘结剂的粘结特性进行了研究。主要结论如下：（1）建立了粘结剂的温度和速率相关的多轴弹粘塑性本构模型。(2)当弯曲内侧板具有高抗拉强度而弯曲外侧板具有低抗拉强度时，通过板的组合，异种板的剪切变形和鸥翼弯曲被抑制。(3)随着被粘物厚度的增加，剪切变形和鸥翼形弯曲变大，在某些情况下会导致分层。(4)使用Marc2005进行空气弯曲（三点弯曲）的数值模拟。计算结果与实验结果吻合较好。

We have recently proposed a new technique of plastic forming of adhesively bonded sheet metals, where two flat sheets, which are the same materials, are adhesively bonded together and then press-formed, which are completely different from the conventional process of adhesive joint. In this technique, suppression of large transverse shear deformation occurring in the adhesive layer during bending is of vital importance, since it would cause the geometrical imperfection of bent sheets (so-called gull-wing bend).In this study, the effects of material characteristics on plastic forming of adhesively bonded dissimilar sheet metals were investigate by experiments and finite element method (FEM) analysis. The analysis considered as two-dimensional plane strain problem. In addition, adhesive characteristics were determined by using the Table function of Marc2005.The main conclusions are summarized as follows:(1) A multi-axial elasto-viscoplasticity constitutive model of temperature- and rate-dependent of the adhesive is presented.(2) In the adhesively bonded dissimilar sheet metals, the shear deformation and gull-wing bend are suppressed by the combination of the sheet metals, when a bending inside sheet has high-tensile strength while a bending outside sheet has low-tensile strength.(3) When the thickness of the adherends increases, the shear deformation and gull-wing bend becomes larger, which in some cases lead to the delamination.(4) Numerical simulation of air-bending (three-point bending) was performed using Marc2005. The correspondence of calculated results to experimental ones is relatively good.