Study of Formability of Sandwich Shells with Metal Foam Cores

The main goal of this work is made a first approach to the study of formability of sandwich structures, composed by two aluminum sheets (skins), separated by an aluminum metal foam core, using bending tests. The bending tests performed on this work, can be described as a cylindrical punch, which apply a force at the middle span of the specimens, which were have three different lengths, 114 mm, 167.5 mm and 230 mm, in a specific die. The bending tests were used to evaluate the type of yielding of the global composite structure, by measuring the force / displacement values at a middle span. The type of yielding of the global structure has extremely importance in the study of formability of this type of composite, because it was composed by two different materials; each one presents a different mechanical behavior separately. The difference in mechanical behavior can be explained by the axisymmetric compressive stress states test and by the influence of the hydrostatic pressure in the yield stress of the porous material (aluminum foam) and has no influence on the yield stress of the homogeneous solid material (aluminum sheet). With this work, experimental information on the yielding of this composite structure was obtained, to be used in numerical models to study its formability.