Vibroacoustic Analysis in the Thermal Environment of PCLD Sandwich Beams with Frequency and Temperature Dependent Viscoelastic Cores

IntroductionThe impact of vibrations excited by incident sound fields has become a major concern today, due to its influence on the performance of systems and installations. Vibrations have the potential to cause considerable dynamic disturbances and instabilities, which can lead to significant structural and functional damage. Consequently, it is crucial to control vibration phenomena right from the system design phase. To solve the problem of vibration, it is sometimes possible to increase the damping level of the structure by incorporating a damping treatment.ObjectiveThe aim of this paper is to present a simplified numerical approach to study the vibro-acoustic responses of structures with PCLD "Passive Constrained Layer Damping" treatment in the thermal environment, taking into account the frequency and temperature dependence of the different viscoelastic behavior laws.Material and MethodsThe modal stability procedure MSP is based on the finite element method in order to discretize and formulate the equation of motion. The asymptotic numerical method "ANM" is applied to approximate the solution of complex eigenvalue problems and construct the modal basis. The variability of the frequency responses is evaluated by a Monte Carlo simulation (MCS) combined with MSP and ANM to evaluate the stochastic behavior of a sandwich beam with random properties.ResultsThe comparison with the direct frequency responses (DFR) demonstrates that the results are highly satisfactory in terms of the validity of the present MSP approach. A comparative study of viscoelastic behavior models was carried out to evaluate their damping properties provided to the structure. The viscoelastic materials provide significant damping particularly for amplitudes corresponding to the high frequencies. This is in contrast to the responses obtained without the viscoelastic layer.ConclusionThe obtained results show the importance of viscoelastic damping, which has a significant effect on the vibro-acoustic behavior, implying the improvement of the damping of the structure, especially for large frequencies and high temperatures.