Energy Absorption and Low-Velocity Impact Responses of the Sandwich Panels with Lattice Truss Core

This study investigates the dynamic energy absorption performance of composite sandwich panels with two different configurations of lattice truss core. Two types of core structures were designed and created using polyamide 12 through the selective laser sintering (SLS) additive manufacturing method. These structures, with uniform and graded cell topologies, were created by changing the geometry and layer density of the body-centered cubic (BCC) unit cell. The cores were used to fabricate composite sandwich panels, which were made with E-glass/epoxy face sheets. Then, their ability to absorb energy during low-velocity impact and quasi-static compressive strength was tested using both experimental and numerical methods. It was found that the graded structure absorbed 10, 5, and 3% more energy than the uniform structure for the energy levels of 12.4, 16.5, and 17.9 J, respectively. It was also found that both structures could absorb at least 90% of the impact energy. In terms of strength, the uniform structure was able to tolerate 1.15 times larger impact loads, indicating its higher strength than the graded structure. The uniform structure had 8% more compressive strength.