An Experimental, Analytical, and Numerical Investigation of Hydraulic Bulge Test in Two-Layer Al-Cu Sheets

The objective of this study is to investigate hydraulic bulge test in double layer sheets, which is based on experimental tests, analytical investigation, and numerical method. Bulge test due to creating plane stress condition on test sheet is extremely similar to sheet metal forming processes, such as hydroforming, stamping, and deep drawing. The results of the bulge test are more accurate and practical for analyzing the sheet forming process than tensile test. In multilayer sheets, the diverse properties of the constituent layers cause favorable properties on multilayer sheets, such as low weight, high strength, better ductility and corrosion resistance, and good thermal and electrical properties at the same time. For these reasons, multilayer sheets are highly useful in automotive, aviation, and chemical industries. Therefore, the necessity of investigating mechanical properties and formability in multilayer sheets is crucially important. During this study, the hydraulic bulge test has been investigated thoroughly, and then accurate analytical relations have been developed for bulge test in double layer Al-Cu sheet. In addition, the hydraulic bulge test in double layer sheets has been investigated by FEM. Finally, analytical and FE results have been verified by experimental tests. The results from the experimental tests are in good consistency with the extracted analytical relations and numerical method in the bulge test of double layer sheets.