Wrinkle Behavior of Hydroforming of Aluminum Alloy Double-Layer Sheets

In this article, the wrinkling behavior and thickness distribution of 5A06 aluminum alloy sheets in an annealed state with thickness of 1.0 mm and 2.5 mm was numerically and experimentally investigated under different hydraulic pressures in the hydroforming of single-layer and double-layer sheets. Note that, in double-layer sheets hydroforming, an upper-aided sheet is needed. The upper, thicker sheet synchronously deforms with the lower, thinner sheet during hydroforming. When the double-layer sheets are separated, a thinner curved sheet part will be manufactured. As can be seen from the simulation and experimental results, the upper, thicker sheet could effectively suppress the wrinkles of the lower, thinner sheet and improve the thickness distribution due to the increasing anti-wrinkle ability of the formed sheet and the interfacial friction between the double-layer sheets. In addition, the maximum hydraulic pressure can be decreased via hydroforming of double-layer sheets; this approach reduces the drawing force for large sheet parts and meets the requirement of energy conservation.