Modelling and Optimization of Lightweight-Sandwich-Sheets with an Adhesive Interlayer for the Forming Process Die Bending

Sandwich sheets with different materials and thicknesses of each layer offer highly use ul properties. Isothermal lap-shear tests and isothermal tensile tests are carried out under various temperatures. With numerical calculations, the stress distribution in the overlapping length can be determined. The stiffness of the cover sheets is compensated numerically and the parameter of the adhesive are calculated for the Traction-Separation-Law. With plastomechanical calculations based on Yoshida, 2004, the forming behaviour can be predicted. Enhanced by the Traction Separation Law with damage description and a calculation of the spring back, the failure modes displacement and delamination can be indicated. The influence of the shifting of the neutral axes and the shear stress in the adhesive on the forming behaviour of the metal layers is shown. Aim of the modelling is an optimization diagram to show the bending limits of sandwich-sheets dependant on the layer-thicknesses and s de lengths.