Investigation of vibro-acoustic characteristics of FRP plates with porous foam core

Both theoretical and experimental investigations are performed on vibro-acoustic characteristics of composite plate comprising fiber-reinforced polymer (FRP) laminates with a porous foam core (PFC) subjected to planar acoustic wave (PAW) excitation in present work. Firstly, a theoretical model of the PFC-FRP plates is established through a combination of the advantages of analytical and finite element methods. The equivalent Young's and shear moduli and density of porous foam core with different porosity distributions is considered. The free and forced vibration equations subjected to PAW load are derived to solve natural frequencies, modal shapes and vibration responses of the PFC-FRP plates on the basis of the first-order shear deformation theory and the four-node quadrilateral isoperimetric finite element method. To solve the acoustic radiation powers (ARP), the Rayleigh integral approach is used to determine the quantitative relationships between the vibration velocity responses and acoustic radiation pressures. The sound transmission loss is further determined with the pre-defined proportional expression involving the ARP and the incident acoustic power (IRP). After the theoretical model is validated coarsely based on the separated literature results, a TC300 carbon/ GEL2 epoxy resin plate specimen is fabricated and an integrated vibro-acoustic experiment system is set up to give further validation of the proposed model, of which vibration and acoustic results are measured simultaneously without changing boundary conditions of the specimen. Finally, a detailed parametric study is conducted to obtain the optimum suppression performance of vibration and noise of this kind of composite plate.