Forming behavior during drawing of aluminum sandwich composite laminate - a comprehensive experimental analysis

The main objective of this study was to analyze the deep drawing behavior of sandwich laminate for various blank shapes and lubrications. Commercially available aluminum sandwich laminate with face sheets made of aluminum alloy, AA2219 and a core made of high-density polyethylene was used for the forming behaviour performance. The laminate was characterized by its mass density, porosity and tensile strength for better understanding the physical and mechanical behavior, being essential for analyzing the forming behaviour. Deep drawing, one of the forming techniques on the laminate was performed with a steel spherical punch for three different blank shapes: circular, square and square with round fillets. Furthermore, three different lubricants Vaseline, grease and soap, were used at the contact regions of the die and laminate. This formation occurred under normal atmospheric conditions. Lubrication significantly influenced the drawing performance in addition to the blank shape. Uniform material flow during the drawing process was achieved in the circular specimen, which in turn resulted in better drawing performance of the laminate. The highest drawing force of 1.425 kN was obtained for the circular specimen with the grease lubricant. A higher-order equivalent plastic strain was observed for the lubricant grease, and the least-order strain was observed for the specimens under dry conditions. The higher the effect of lubrication, the lower the friction between the punch and specimen, which in turn resulted in a higher order strain and subsequent reduction in the thickness of the specimen.