Abstract:
Considering the effect of non-linear factors, this article set static response as initial condition for the dynamic response analysis of the underground structures under dynamic loads. Since there is zero frequency restriction on some local artificial boundary conditions such as transmission boundary and viscous boundary etc., the initial condition of static response cannot be directly applied to the dynamic system simulated by those artificial boundary conditions. Fixed boundary used to be applied during the static analysis, and the reactive force on the boundary used to be regarded as the boundary constraint force in the stage of the dynamic analysis. As a result, the boundary conditions of static and dynamic analysis were not uniformed. In this article, the viscous-spring boundary without zero frequency restriction was applied to the non-linear dynamic response analysis of the underground structure under dynamic loads, by which the uniform boundary conditions between static and dynamic analysis were achieved. At last the algorithm was implemented in the explicit FEM program LS-DYNA by the example of dynamic response analysis of the underground structure under explosive loads.