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

我们最近提出了一种新的粘接金属板材塑性成形技术，它是将相同材料的两个平板粘接在一起，然后压制成形，这与传统的粘接工艺完全不同。在这项技术中，抑制弯曲过程中粘结层的大横向剪切变形至关重要，因为它会导致弯曲板材的几何缺陷(即所谓的鸟翼弯曲)。本文通过实验和有限元分析研究了材料特性对粘接异种板材塑性成形的影响。分析认为是二维平面应变问题。(1)建立了粘结剂温度和速率相关的多轴弹粘塑性本构模型。(2)在粘接异种金属板材中，当板材内侧弯曲抗拉强度较高，而外板弯曲强度较低时，板材组合对剪切变形和鸟翼弯曲有抑制作用。(3)随着粘结体厚度的增加，剪切变形和鸟翼弯曲增大。利用Marc2005对空气弯曲(三点弯曲)进行了数值模拟。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.