Impacts of pressure and pre-stress loads on the vibroacoustic response of laminated composite structures

This study investigates the effects of tensile pre-stress, compressive pre-stress, and surface pressure loads on the vibroacoustic behavior of laminated composite panels using a wave-based Statistical Energy Analysis (SEA) framework. A Wave Finite Element (WFE) method is used to compute wave dispersion, which informs the calculation of modal density, acoustic radiation efficiency, and sound transmission loss (STL). The numerical framework is validated against benchmark experimental and numerical results, with maximum discrepancies below 10%. Results reveal that tensile pre-stress decreases dispersion and modal density while shifting the coincidence frequency downward – from 15.2 kHz (0 N) to 5.1 kHz (100 N). In contrast, compressive pre-stress increases modal density and raises the coincidence frequency, reaching 108.5 kHz at 400 N. Surface pressure primarily affects low-frequency dynamics, increasing dispersion and reducing modal density, with STL coincidence frequency shifting from 12 kHz (0.6 GPa) to 20 kHz (0 GPa). Under combined loading, the dynamic response is intermediate, with pre-stress modulating the out-of-plane stiffening effect of pressure. These results offer critical insight for tailoring vibroacoustic performance in lightweight composite structures, particularly in aerospace and transport systems subjected to operational loading.