Lightweight structures: An innovative method to uniform the thickness of metal sheets by patchwork blanks

Metal sheet forming is widely used in industrial field. Generally, the use of patchwork banks allows the manufacturing of a more uniform thickness of the formed parts. Often, they are obtained using welding techniques: in these cases, distortions and localized metallurgical transformations could have detrimental effects on the mechanical performance. Moreover, it is not possible to weld very thin patches. In this paper, an innovative approach based on bonded patches has been developed and investigated. In this manner, it is possible to adopt thinner patches, doing away with the problems arising from the welding process. Experimental tests showed the potentiality of using adhesives in forming processes to influence the thickness distribution. Moreover, the commercial code PAM-STAMP has been used for modelling the forming process. In this way, the effects of the thickness of the patch and the friction conditions on the strain state generated on the patchwork blanks have been investigated.