Abstract
It is essential to predict train-induced vibration level by a numerical analysis with development of railroad technology. A 3-D analysis is required to obtain environmental vibration properties around a barrier with finite length produced by a moving load. In practice, however, a 3-D analysis using the conventional boundary element method requires too much computational time and memory. Therefore, it is necessary to develop a more effective numerical method for a 3-D environmental vibration analysis. In this paper, we propose the coupling method of a 2.5-D boundary element method and a 3-D Fast Multipole Boundary Element Method (FMBEM) to improve the computational efficiency for the dynamic problem due to a moving load. Firstly, a 2.5-D analysis is used to obtain the solution of a wave field produced by a moving load on a half space. Secondly, an FMBEM analysis for the time harmonic scattering problem by a finite barrier is carried out using the 2.5-D solution as an incident wave field. Finally, the time variation of the wave field for a train load moving in a parallel direction to the barrier is calculated by using the Fourier transform as numerical examples.
