Roll formability of aluminium foam sandwich panels

An aluminium foam sandwich (AFS) material was formed by V-die bending and roll forming. The V-bent sections showed material failure by shear fracture of the aluminium foam core and by delamination at the core-cover sheet interface. This led to a high-gull wing defect and a limited section depth that could be formed. In contrast, the roll forming process allowed the manufacture of long sections with acceptable profile depth. Only minor gull wing was observed, and this was related to a low-shear deformation of the aluminium foam core and an intact adhesion at the core-cover sheet interface. The higher material formability observed in roll forming compared to that in V-die bending was attributed to a more evenly distributed contact pressure and more homogeneous forming, due to the incremental nature of the process, combined with a continuous contact of the metal sheet with the top and bottom rolls. Some forming problems were also observed in the roll-formed AFS components, but overall, the results of this study suggest that roll forming represents a good alternative to bending or stamping for the forming of longitudinal components of simple cross section shape that are of interest to the transport, solar or housing industries.