On global bending-shear core transition effects for the vibroacoustic of sandwich structures: Analytical and numerical investigations

The present paper investigates the vibroacoustics of honeycomb sandwich panels using both analytical and numerical approaches. In a typical sandwich structure, the acoustic transmission in the low and mid frequency ranges is generally controlled by global bending waves and by core shear effects. This behavior defines two frequency bands of great interest for the vibroacoustic signature. The transition frequency is then an important parameter to predict. In the present work, transition frequency expressions of honeycomb sandwich panels are derived using both a homogenized analytical method and a three-dimensional numerical approach. The expressions obtained show the panel geometry and the core properties influence. Also, they take into account the orthotropic effect of the entire panel and the transverse shear effect of the sandwich core. The accuracy of the predictions based on the two approaches has been verified by comparing the results obtained with previously published analytical models, showing a good agreement as far as the sandwich panel exhibits an isotropic behavior. However, when the orthotropic behavior of the sandwich panel becomes important, corrections are needed and provided.