The present work aims to study the dynamic stability of a three layer sandwich beam with viscoelastic core and functionally graded material constraining layer. Sandwich beam is modelled as a line element having two nodes of each having four degrees of freedom. Finite element method is used to model the beam. Variation of properties of functionally graded material is taken according to a simple power law. The Hsu’s procedure proposed by Saito and Otomi has been used to determine boundaries of stable and unstable regions of the sandwich beam. The effect of various system parameters such as core thickness ratio, power law index, core loss factor etc., on the dynamic stability of the sandwich is studied theoretically. For the fixed- free sandwich beam buckling load decreases with increase in power law index. The frequency parameter first decreases and then increases for increase in power law index and core thickness ratio parameter. Fundamental loss factor of sandwich beam increases with increase in the core loss factor. Increase in core thickness ratio, first decreases and then increases the fundamental loss factor. Increase in power law index values, shows more probability of instability of beam. Increase in thickness ratio also enhances the instability chances of sandwich beam.
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