Acoustic wave transmission characteristics of stiffened composite shell systems with double curvature

Abstract

In this study, acoustic performance of the stiffened doubly curved shells is studied for the first time. Since these structures reinforced via equally spaced stiffeners are found in many engineering designs, the inspection of their sound insulation is remarkably recommended. For sound analysis of such models, it is essential to provide a solution strategy wherein the acoustic equations to be simultaneously solved besides the stiffened shell equations. Accordingly, based on modeling the construction as a finite shell using shear deformation shallow shell theory (SDSST), wave propagation is performed through a doubly curved body reinforced by a stiffener. Before validating the sound transmission loss (STL) spectrum with previous outcomes, the convergence criterion is checked. Moreover, the acoustic efficiency of the proposed stiffened system is also evaluated. It is shown that the stiffened model using both ring and stringer improves the sound characteristics of structure in the entire frequency domain. Finally, an optimization scheme based on genetic algorithm (GA) is presented to maximize the STL and minimize the weight of the structure focusing on geometrical characteristics of the stiffener. This study proposes a strategy that can be applied to predict the acoustic features of the stiffened systems to achieve better sound insulation.