Mechanical behavior of sandwich panels with 3D printed polymeric cores under static and dynamic loads

In past years, the use of additive manufacturing technology and the capability of different core cell geometry have significantly contributed to the development of advanced components based on lightweight structures and high mechanical strength. This work shows a numerical and experimental analysis of the mechanical behaviour of new sandwich panels, with cores manufactured by the fused deposition modeling (FDM) method. PLA and ABS polymeric cores with 2024-T3 aluminium alloy sheets as facings are analyzed. Three core shapes are investigated: out-of-plane hexagonal honeycomb, S-shape corrugated, and in-plane hexagonal honeycomb. Using a full factorial design, the experimental conditions are tested under three-point bending, Charpy impact and ballistic tests. Numerical modelling using Ansys Software is performed to obtain the energy absorbed and the failure mode of the panels in the ballistic tests. The experimental ballistic tests are made in a new piezoelectric sensor-based monitoring system. In the bending tests, sandwich panels with in-plane hexagonal honeycomb PLA core showed the highest average values for flexural modulus and flexural strength. On the other hand, ABSAL panels with S-shape corrugated cores had higher energy absorbed in the Charpy impact. Numerical analysis of ballistic impact showed greater energy absorption by ABSAL panels. The experimental tests validated the numerical simulations, showing high energy absorption by the in-plane hexagonal honeycomb core, with concentrated fractures in the region close to the impact, and good impact resistance by panels with out-of-plane hexagonal honeycomb and S-shape corrugated ABS cores. The feasibility of producing sandwich panels with 3D-printed polymeric cores and 2024-T3 aluminium alloy facings achieves suitable mechanical properties for structural applications, especially when lightness, stiffness, and high energy-absorption capabilities are required.