Mechanical behavior of reinforced Al2O3 lattice structures: Effects of structural parameters from experiments and simulations

The pressure hull is one of the core components of autonomous underwater vehicles (AUVs), necessitating a new structural material with improved mechanical and lightweight properties. For this purpose, a novel type of reinforced lattice structure (RLS) that integrates Al2O3 lattice structures (ALSs) with phenol-formaldehyde (PF) resin was designed and fabricated via stereolithography (SL)-based additive manufacturing and infiltration processes. The responses of the RLSs with different structural configurations, relative densities, and unit cell sizes under compressive loading were systematically characterized. Additionally, numerical simulations were conducted to further predict and study the mechanical behavior of the RLSs using Johnson-Holmquist-II (JH-2) model. The results revealed that the mechanical properties of the RLSs from superior to inferior were simple cubic (SC), body-centered cubic (BCC), Gyroid, octet truss (Oct), and SchwarzP (Sch). As the relative density and the unit cell size increased, the mechanical properties of the RLSs increased. Furthermore, the results of the numerical simulations closely aligned with the experimental results, which provided an in-depth analysis of internal damage and crack propagation in the RLSs under compression. A comparison of the mechanical properties also demonstrated that RLSs exhibit superior compressive strength and energy absorption performance than traditional ALSs do. After this investigation, this type of RLS is anticipated to facilitate lightweighting of AUVs, advancing the development of deep-sea scientific research.