接着接合した金属薄板の塑性曲げに及ぼす加工速度の影響

抄録

The present authors proposed a new technique of plastic bending of adhesively bonded sheet metals. In this process, large transverse shear deformation occurs in the adhesive layer, which in some cases would induce the geometrical imperfection (so-called 'gull-wing' bend) and the delamination. Since the strength of the adhesive is highly rate-sensitive, the amount of shear deformation of the adhesive layer and, as a result, 'gull-wing' bend, are strongly influenced by the forming speed. In the present work, the effect of forming speed on the deformation characteristics of adhesively bonded aluminum sheets was investigated by performing V-bending experiments with various punch speeds at room temperature. In order to discuss the effect quantitatively, the numerical simulations for the bending were also conducted using a rate-dependent constitutive model of plasticity for the adhesive. Consequently, it was found that the large shear deformation and 'gull-wing' bend are suppressed by high-speed forming since the deformation resistance becomes higher at high strain rate.