Interpretation of Capsule Barrier Vibration Isolation Technique Based on the Displacement Discontinuity Model

ABSTRACT With the increase in buildings and population density, the vibration hazards caused by rail transit and engineering construction cannot be ignored. However, traditional propagation path isolation methods all have disadvantages, and the research on the isolation effects of different materials is also incomplete. In this study, the vibration isolation effect of different capsule materials under different propagation fields was compared by finite element method simulation; the time domain and frequency domain analyses were carried out. This study used the displacement discontinuity model (DDM) to explain the mechanism of the capsule barrier, a new vibration isolation technology, and the reason for the difference in the vibration isolation effect of different materials was clarified by using the barrier dynamic stiffness. It is found that capsule barrier isolation technology has significant isolation effects. The barrier dynamic stiffness based on the DDM uniformly explains that the isolation effect depends on the strong stiffness contrast between the field and the filling materials. The barrier dynamic stiffness significantly affects the isolation rate. In both time and frequency domains, the isolation rate increases while the barrier dynamic stiffness decreases. The findings can guide the selection of filling materials for vibration isolation engineering, simplify engineering difficulty, and shed light on a better understanding of the theoretical system of vibration isolation.