| Vibration analysis by finite element method for spiral tubes conveying fluid is presented in this paper. Based on the Hamilton's principle, the element mass matrix, stiffness matrix, and damping matrix attributed to Coriolis force are derived. Effects of flow velocity, Coriolis force, boundary conditions, and pitch angle on natural frequencies of spiral tubes are discussed. A two sided Ritz vector method is proposed in the paper for the nonclassically and asymmetrically damped systems, and comparisons of this method and HQR method in calculation accuracy and in CPU time are given in the end of the paper. |