Vibration of hollow cylindrical shells with partial constrained layer damping

A theoretical analysis is presented for determining the natural frequencies and damping factors for isotropic circular cylindrical shell type structures. Equations of motion for a cylindrical shell and a three-layer cylindrical shell fully and partially treated, with a viscoelastic core, are derived from equilibrium. The assumed mode method or Galerkin method are used to find the equivalent mass and stiffness matrices from which the natural frequencies can then be obtained. The effects on the natural frequency and damping factor due to various viscoelastic core thicknesses, viscoelastic shear moduli, constraining layer thickness, constraining layer Young\u27s moduli, and viscoelastic coverage length are discussed. The results reveal for the cylinder studied, that an optimal coverage length exists for achieving maximum damping, along with an optimal viscoelastic shear modulus