Loss Factors and Resonant Frequencies of Periodic Damped Sandwich Plates

This paper describes a method of determining loss factors and resonant frequencies of three-layer, damped sandwich plates with regularly spaced stiffeners spanning the plate in one direction. Periodic structure theory is used in conjunction with the theory of damped forced normal modes. Computed results are presented which show how loss factors and resonant frequencies are affected by the presence of the stiffeners and their attachment rivets, by the stiffener spacing, and by the shear stiffness of the sandwich core.