Free Vibration Analysis of Beam-Type Structures Based on Novel Reduced-Order Model

For the structural dynamic analysis of complicated beam-type structures, a detailed finite element model with large number of degrees of freedom is almost impossible to be used due to the huge computational cost and storage requirements. Therefore, a novel reduced-order model is proposed to determine the natural frequencies of the beam-type structures in this study, which is established by using a reduction basis along with the polynomial interpolation function. The basic idea is to convert the displacements of finite element model nodes in each cross section to a small set of nodes with a few generalized degrees of freedom. The proposed reduced-order model can gain a significant reduction of computational cost without sacrifice of accuracy; moreover, it has the ability to identify shell lobe-type modes and coupled modes. Several numerical case studies for different beam-type structures, including thin-walled cylinder, stiffened shells, and thin-walled cylinder with cutouts, are studied, and the outcomes are validated by benchmark studies.