Bending behavior of sandwich composite structures with tunable 3D-printed core materials

We combine 3D printing technique, numerical analysis, and experiments to design a new class of sandwich composites that exhibit various bending behaviors. These programmed sandwich structures contain 3D printed core materials with truss, conventional honeycomb, and re-entrant honeycomb topologies. Three-point bending tests are performed to investigate the bending behavior of these sandwich composites with two types of carbon fiber reinforced polymer face sheets. Under bending deformation, sandwich composites with truss core materials provide highest flexural stiffness and strength that are desirable in structural components. The sandwich composites with re-entrant honeycomb core exhibit a sequential snap-through instability which significantly enhances the energy absorption abilities. Our experimental and numerical results indicate that architected core structures can be utilized to tailor the bending properties as well as failure mechanisms. These findings offer new insights into the study of nonlinear mechanical response of sandwich structures, which can benefit a wide range of industries and applications.