Sound transmission across composite laminate sandwiches: Influence of orthogonal stiffeners and laminate layup

A theoretical model is developed to predict sound transmission loss (STL) across periodically and orthogonally stiffened composite laminate sandwich structures. The first order shear deformation theory (FSDT) is employed to describe the top and bottom composite laminate plates whilst the longitudinal and rotational motion equations are utilized to characterize the reaction forces and moments of the stiffeners. By taking advantage of the periodicity of the sandwich, the governing vibroacoustic equations are favorably solved by employing the method of space harmonic expansion. The validity and feasibility of the proposed theoretical model is qualified through comparisons with finite element simulation results. It is demonstrated that both the stiffeners and laminate layup have significant effects on the vibration and sound radiation behaviors of the structure, especially in the mid and high frequency regimes, enabling further acoustic optimization design.