Prediction of sound transmission loss of honeycomb sandwich panel by higher order approach

People have studied the sound transmission loss (STL) of sandwich panels since the 1970s. However, most of the existing prediction methods have been based on single-layer dynamical models, neglecting the symmetric (dilatational) movements of the skins. Consequently, the symmetric coincident frequency of the sandwich panel cannot be predicted using those approaches. To account for this dilatational motion of the sandwich structures, different methods were utilized. However, most of them were based on one dimensional sandwich beams theories. The authors have also applied the consistent higher order beam approach to calculate the sound transmission loss of a unidirectional sandwich panel. Although the one dimensional approximation is good in predicting STL, the effects of some factors, such as the anisotropy and orientation of the principle axis of the panel, cannot be estimated. In the current work, the authors extended that one dimensional beam model into two dimensions, which allows us to calculate the STL of sandwich plates with composite laminate face sheets and honeycomb core. Both flexural (antisymmetric) and dilatational (symmetric) motions of the sandwich panel were considered in the study. The predictions were finally compared with our experimental data.