An Assessment of Fully Integrated Polymer Sandwich Structures Designed by Additive Manufacturing

Abstract

3D printing is an additive manufacturing technique (AM) widely used in the aerospace, shipbuilding, automotive and civil construction sectors to obtain lightweight sandwich structures made with complex core shapes to achieve excellent multifunctional properties, such as flexural stiffness, and high energy-absorption capabilities. This study shows an experimental analysis of the mechanical behavior of three types of core, including (i) out-of-plane and (ii) in-plane hexagonal honeycomb, and (iii) S-shape corrugated core. The fused deposition modeling method (FDM) is applied in the manufacture of fully integrated sandwich structures using polylactic acid (PLA) biopolymer filaments. Tensile, flexural and Charpy impact tests are used for the experimental investigation. The failure modes of polymeric structures are analyzed. The out-of-plane -comb and S-shape corrugated panels achieve similar mechanical behavior, however, superior tensile modulus, tensile strength, flexural modulus, flexural strength and energy absorbed are obtained in comparison with in-plane -comb core panels. Sandwich panels fabricated by AM achieve acceptable mechanical properties for secondary structural applications, especially when lightness is required.