Dispersion characteristics analysis of box girder structure based on virtual spring model and variational principle

Abstract

The box girder structure is widely used in engineering. The study of its dispersion characteristics is of great significance to clarify the mechanism of its vibration propagation and sound radiation. However, its dispersion analysis is currently relies mainly on the finite element method due to the relative complexity of the box girder structure model, and although FE-based methods are an effective means to simulate the dispersion characteristics of box girder structure, they are not as favorable or convenient as the analytical or semi-analytical methods to perform a deeper investigation of the parameters and mechanisms involved in this process. Therefore, this study develops a semi-analytical method based on the energy method to analyze the dispersion characteristics of the box girder structure, with the core idea being the use of virtual springs to simulate the Bloch boundary; this successfully corrects for the complications of constructing displacement functions that satisfy Bloch boundary conditions in the traditional energy method, and it can improve the calculation efficiency. Then, the box girder structure is simplified to a spatial plate coupling model, and its dispersion control equation is established using the variational principle. This paper studies the propagation characteristics of elastic waves in a box girder, and the accuracy of the method is verified by finite element simulation.