A non-linear FE – direct BE based numerical model for vibroacoustic response analysis of composite double-leaf structures under thermo-mechanical excitation

Composite double-leaf structures are widely used in aerospace and automotive components due to their low weight and high strength to weight ratio. During service, these structures are subjected to dynamic mechanical excitations and elevated temperature, which pose significant challenges to structural integrity, operational safety and acoustic insulation. Hence, the vibroacoustic energy transmission behavior of composite double-leaf structures in a thermal environment is investigated in the present research work. A coupled numerical framework is developed by integrating a non-linear strain-based finite element (FE) method with a direct boundary element (BE) approach for conducting the vibroacoustic analysis. Results indicate that the frequency shifts of structural panels due to thermal softening reach approximately 30–50% in different configurations, which enhances structural-acoustic coupling and thereby increases radiated sound energy by up to about 23% in certain cases. Furthermore, the incorporation of structural stiffeners on Panel I is shown to be an effective mitigation strategy, resulting in a reduction in radiated sound power of approximately 22% for unidirectional stiffener and up to 31% for bidirectional stiffener arrangements. In general, symmetric laminate configurations are found to provide better acoustic insulation. Moreover, symmetric cross-ply laminates show attenuated vibroacoustic response in the mid-frequency range (400–600 Hz).