Sound transmission loss and energy absorbing performance of stiffened doubly-curved shells with corrugated-honeycomb hybrid cores

Compared to traditional lightweight corrugation and cellular cores, the novel cellular cores auxetic meta- materials with negative and zero Poisson's ratios possess distinctive mechanical deformation traits, making them suitable for modeling lightweight sandwich structures. Therefore, the concept of combining auxetic metamaterial cellular with folded corrugation is proposed to construct a new type of corrugated honeycomb hybrid cores for studying the sound insulation and energy absorption characteristics of the stiffened sandwich doubly-curved shells, wherein the honeycomb core possesses a full range of Poisson's ratio characteristic and is composed of cellular cores exhibiting positive, negative, and zero Poisson's ratios (PPR, NPR, and ZPR). The Hamilton's principle is hired to derive the governing equations and considers fluid-structure coupling by applying normal velocities continuity conditions at the fluid-structure interface, which is further analytically solved using Navier's techniques, and the sound transmission loss (STL) is described analytically. The accuracy of these results is validated through comparisons with both experimental measurements conducted in an impedance tube and simulated outcomes generated by the COMSOL commercial software. The properties of stiffened sandwich doubly-curved shells with corrugated honeycomb hybrid cores are meticulously evaluated and compared, and the results show that the hybrid cellular core type significantly impacts the STL, wherein the average STL of the corrugation ZPR cellular hybrid cores stands at 42.06 dB within the broad low-frequency range of 380-2422 Hz, which has increased by 9.11% and 8.31% compared to the values of the corrugation NPR and traditional PPR cellular hybrid cores, the specific energy absorption (SEA) of the corrugation ZPR cellular hybrid cores is 13.06 kJ/m3, 3 , which has increased by 16.19% and 18.08% compared with the corrugation NPR and PPR cellular hybrid cores, respectively, indicating that the corrugation ZPR cellular hybrid cores have better sound insulation and energy absorption characteristics than the corrugation NPR and PPR cellular hybrid cores.