3D printed architected polymeric sandwich panels: Energy absorption and structural performance

Lightweight architected cellular cores have been introduced as an advanced alternative to improve the overall performance of sandwich structures. In this study, we implement semi-analytical and finite element approaches and conduct experimental impact tests to evaluate the performance of 3D printed lightweight sandwich panels with architected cellular cores of programmable six-sided cells. Changing the geometrical parameters of the cells leads to cellular cores of hexagonal, rectangular and auxetic topologies. A semi-analytical methodology is developed for conducing structural and low-velocity impact analyses based on a modified higher-order shear deformation theory. The standard mechanics homogenization is implemented through finite element modelling to accurately predict the effective mechanical properties of architected cellular cores. We apply explicit large deformation finite element analysis using ANSYS to analyze the elasto-plastic behavior of architected sandwich panels under a low-velocity impact. To experimentally corroborate the developed theoretical and computational models and to evaluate the manufacturability of the architected sandwich panels, we use the fused deposition modeling to 3D print samples of polylactic acid biopolymers. Uniaxial tensile test is first used to characterize the polymer. We then conduct low-velocity impact tests to investigate the energy absorption capability of architected sandwich panels. X-ray micro-tomography is finally employed to study the microstructural features of panels before and after the impact. The experimental and numerical results show that the auxetic sandwich panel is potentially an appropriate candidate for energy absorption applications due to its high-energy absorption capability and a minimum response force transferred from the 3D printed panel.