Hybrid structures in Titanium-Lattice/FRP: effect of skins material on bending characteristics

Lattice structures represent a valuable solution for applications demanding both high mechanical properties and lightweight. However, the skin is required to obtain uniformity of the load distribution and avoid stress concentration. The characteristics of the skin materials can influence the mechanical properties of the structure; therefore, in the present work the bending properties of various kinds of lattice-cored structures, with different skin materials, were investigated by means of experimental tests. In particular, flat lattice panels were produced by the Electron Beam Melting process. Then, composite material skins were added to these cores through the autoclave-vacuum bagging process. Three types of reinforcement were adopted for the skin: carbon, aramid, or glass, and the produced sandwich specimens were subjected to a three-point bending test in order to evaluate the flexural characteristics. The experimental tests showed that the specimens with the carbon skin were able to reach the maximum load, but presented the lowest ultimate transversal displacement. On the contrary, the aramid skins were characterized by the highest applied displacement and the lowest failure load.