A study on the mechanical properties and springback of 3D aluminum sheets

Three-dimensional (3D), cone-shape embossed aluminum sheets are used in automotive exhaust systems to increase their heat dissipation efficiency by increasing the surface area. However, the manufacturing process has various restrictions because wrinkling occurs easily during the press forming process. In this study, A tensile test and a bending test were performed to investigate the mechanical properties and springback characteristics of 3D aluminum sheets. We clarified how the direction in which the specimen is cut affects the tensile properties. The results of the tensile test showed that the characteristics of the parallel and diagonal direction specimens differed from each other and those of the as-received flat sheet. The 3D aluminum sheets had a smaller Young’s modulus and smaller flow stress than the as-received flat sheets in the small plastic range due to the flattening effect of the embossed cone shapes. However, as the plastic strain increased, the flow stress followed the as-received flat specimen’s flow stress curve because the cone-shape was flattened according to increases in the plastic strain. The yield stress increased in the diagonal-direction specimen and decreased in the parallel-direction specimen. The change in Young’s modulus in the 3D sheets affected the amount of springback.