Incremental Sheet Forming of Steel/Polymer/Steel Sandwich Composites

Formable three- or multi-layer metal/polymer/metal sandwich sheets are interesting functional materials replacing pure metallic sheets in various applications due to the arbitrary tailoring of their mechanical properties and thicknesses delivering the application-related properties. Forming of such sandwiches is often more limited compared to mono-metallic sheets due to load conveying mechanism through the thickness. To extend and improve the forming potential of the sandwich sheets, single point incremental forming was used for first tests shaping conical profiles with variable and constant wall angles in addition to semi-spherical ones. The forming limits were identified in terms of the limiting wall angle, part height and the surface strains determined by digital image correlation. The results reveal that shaping of the sandwich composites sheets is possible similar to monolithic metal sheets, but with earlier failing by cracking. Additionally, the sine law used normally to describe the thickness at failure of SPIF was applied and verified.