Vibration and damping analysis of unconstrained damped plate based on randomness of viscoelastic damping layer

The vibration and damping analysis of an unconstrained damped plate based on randomness of viscoelastic damping layer is studied using the Monte Carlo method in this paper. The random variables follow normal distribution in this analysis. The influences of real modulus, imaginary modulus and loss factor of viscoelastic material on the resonant frequency and the modal loss factor of the structure with different thicknesses of damping layer are analyzed. The influences of thickness of damping layer as a random variable over the whole structure and within each element are analyzed. Numerical examples show that the influence of complex modulus on resonant frequency is not significant but is considerable on modal loss factor and the influence of damping layer on modal loss factor is very notable. Therefore, the randomness of viscoelastic damping layer obviously influences the resonant response and sound radiation of structure. The influence of damping layer as random variable within each element shows that the random analysis for viscoelastic damped structure is necessary.