Abstract
An analysis for vibration of cylindrical shallow shells with a constrained viscoelastic layer and metal layers is presented. In this paper, vibration damping properties of three layer type shallow shells with viscoelastic material are analyzed from both of SEM (Strain energy method) and CEM (Complex eigenvalue method). Furthermore, behavior and accuracy of each solution are examined. Eigenvalue and eigenvector (displacement functions) are analyzed based on the Ritz method, when natural frequency, modal loss factor and strain energy are obtained. In method (CEM), the elastic modulus of viscoelastic material is dealt with complex quantity considering material loss factor. The eigenvalue problem that is derived by means of minimizing the energy functional, is solved to determine the natural frequencies and modal loss factors. In method (SEM), modal loss factor is defined as a ratio of damping energy (strain energy consumed in viscoelastic layer) dissipated during a vibration cycle and total strain energy of the shell. The accuracy and validity of the present results from two methods are illustrated through investigation of convergence and comparison with the established results from the literature. From thebehavior of the solution, consideration and interpretation are tried with respect to accuracy and characteristic of each solutionmethod.
