Vibration and Acoustic Response of Sandwich Panels with Flexible Core Under Thermal Environments

Abstract

Sandwich panels are increasingly used in the aerospace industry in recent years. Aircrafts are always affected by the thermal and noise environment during their life in service. Analytical studies on the sound vibration response of the sandwich panels with flexible core under thermal environments are performed in the paper. Governing equations are obtained by applying Hamilton's principle with both anti-symmetric and symmetric motions taken into consideration. Natural frequencies, mode shape and critical temperature are acquired with thermal stresses considered. The forced vibration response and sound radiation are obtained based on the mode superposition principle and the Rayleigh integral. The model is validated compared with the results in literature. Natural frequencies for both anti-symmetric and symmetric motions decrease with temperature rise. Lower order flexural mode and higher-order dilatational mode are sensitive to the temperature change. Symmetric motion induces the anti-resonance frequencies move to the low frequency range. The peaks of sound vibration response remove to the low frequency range as the temperature rise and the amplitude of the peaks decrease due to the enhanced damping.The proposed model may serve as an effective guideline for the application of sandwich panels in thermal environments.