Dynamic Response Analysis And Simulation Of Under-ground Structure Based On Redevelopment Of ANSYS

With the accumulation of seismic disaster data and the development of scientific research, people have gradually realized the deficiency of pseudo-static mechanics method when analyzing the seismic response of underground structure. On the other hand, the dynamic finite element method is considered to be preferable. The main research work of this paper focuses on the application of this method to the seismic response analysis and simulation of underground structure, which could be summarized as the following four aspects.1. The research advances of seismic response analysis of underground structure as well as horizontal layered soil site are briefly summarized. Thereafter, the limitation of existing methods and the main studies done in this paper is pointed out.2. Based on redeveloping skills, an approach is put forward to realize the organic combination of ANSYS, a general purpose finite element modeling program, and LAND, a procedure developed by Institute of Engineering Mechanics, China Seismological Bureau, for numerically solving two-dimensional wave motion problems. This approach can greatly enhance the capacity of preprocess and post process of LAND, while improving the computational efficiency and accuracy of ANSYS when dealing with dynamic problems at the same time.3. Via programming in APDL and UIDL language, an additional software package is developed to simulate the multi-transmitting boundary by adjusting the displacement of nodes on the artificial boundary in every iteration when dynamic response of soil-structure system is analyzed with ANSYS. This software package shares data with ANSYS solver through inner arrays. The results of numerical examples manifest that this approach can improve the computational accuracy of ANSYS in dynamic response analysis of underground structure.4. Based on the previous study of Li Xiaojun, a incremental-iterativeIIscheme is presented, which is used to discretize the dynamic equation. Combining the dynamic nonlinear constitutive model of soil presented by Pyke, the multi-transmitting boundary condition presented by Liao Zhenpeng and the numerical integral method mentioned above, a new approach is proposed to predict the nonlinear seismic response of horizontal layered soil site and a computer program is worked out with the help of the same ideas. As is demonstrated by numerical examples, this approach can significantly improve the simulation of the nonlinear characteristics of soil site under strong seismic motions.