Abstract:Free vibration characteristics of viscoelastic sandwich circular plate is presented. Based on the basic assumption of elastic thin plate and Kelvin Viogt constitutive equation, the vibration control equation of the viscoelastic circular plate is established. The analytical expression of natural frequency and modes of free vibration is derived by employing the method of separated variables. The natural frequency of fixed and simply supported sandwich circular plate are calculated respectively. The results are compared with finite element method. The influence of core ratio on natural frequency and damping coefficient is discussed. Conclusions are as follows: (1) The natural frequency increases at first, then decreases with the increase of core ratio. It is more obvious for high order frequency. (2) The damping coefficient always increases with the increase of core ratio.