Effect of production angle on low cycle fatigue performance of 3D printed auxetic Re-entrant sandwich panels

This study explores the static and fatigue behavior of re -entrant sandwich structures fabricated via 3D printing to assess their energy dissipation capability and durability. Various core structures of sandwich panels with different angles are considered for analysis. The shells, cores, and the entire sandwich structures are manufactured using polylactic acid (PLA) material. A combination of numerical simulations and experimental tests were employed to evaluate the energy absorption capacity and stiffness of re -entrant sandwich structures. Initial mechanical properties of the core structures were obtained through static tensile testing and the experimental fatigue analysis was carried out by using an Instron 8871 servo hydraulic test device, following the principles of the three-point bending test. The results of both static and fatigue analyses evaluated and the energy absorption capacity of the structures increases with increase in production angles. FEM and experimental results are compared and both results are in good agreement with eachother. Additionally, affect of changes in the geometry of re -entrant sandwich panels evaluated in terms of Young ' s Modulus and Poisson ' s ratio. The improved structures characterized by a negative Poisson ' s ratio hold significant innovation potential, especially in the defense and automotive industries, through the integration of various topological research findings.