Numerical and experimental study on pressure resistant and vibro-acoustic characteristics of an optimized lightweight SRE ZPR sandwich cylindrical shell

• A lightweight pressure-resistant SRE ZPR sandwich cylindrical shell is designed and fabricated with metal 3D-printed techniques. • The designed structure can bear hydrostatic pressure of 1000 m depth and yields a weight-bulk ratio of 0.56 g/cm 3 . • The cell stress distribution within the macroscopic structure is investigated with the inner shell both unconstrained and constrained. • The ZPR sandwich cylindrical shell exhibits greater vibro-acoustic behavior than a comparative PPR one in the mass-controlled frequency region. • Static and acoustic experimental study can validate mechanical and vibro-acoustic numerical simulation. This study proposes a lightweight cylindrical sandwich structure with a semi re-entrant zero Poisson’s ratio (SRE ZPR) core, designed to simultaneously address pressure resistance and vibro-acoustic attenuation for underwater applications. A micro-structural optimization is applied based on periodic boundary conditions (PBCs), and a ZPR sandwich cylindrical shell with a mass density of 0.56 g/cm³ is then designed. Numerical analysis is conducted to evaluate pressure-resistant behavior to demonstrate the efficiency of microstructural optimization. A static experiment is then carried out on a 3D-printed titanium alloy specimen. In addition, both numerical and experimental investigations are performed to study its vibro-acoustic behavior. Results demonstrate that the designed sandwich cylindrical shell can withstand a 10 MPa hydrostatic pressure (1000 m seawater depth) without failure or buckling. It also yields greater vibro-acoustic performance than a comparative positive Poisson's ratio (PPR) shell structure especially in the mass-controlled frequency region, which mainly stems from reduced acoustic impedance of the ZPR sandwiched core.