Analysis of natural vibration characteristics and seismic response of grid structure

The grid structure is a better form of large-span roof structure. It has the advantages of space stress, steel saving, large space rigidity, small building height, ease of industrialization, stereotypes, and beautiful architectural appearance. With the development of economy and the continuous progress of science and technology, the structural form of space grid is increasingly used in architecture. However, due to the frequent occurrence of earthquakes and other natural disasters year by year, how to carry out the seismic design of the grid structure has become an important issue of concern to people. Therefore, the study of the seismic response of the grid structure has certain practical significance, and its conclusions can be used as reference for engineering practice. .

The research work of this article mainly consists of the following parts:

(1) The general principles of finite element theory, the functions of finite element analysis software ANSYS, and the process of typical analysis problems are briefly introduced, and the general principles that should be followed to determine the geometric parameters of the finite element model of the grid are given, using ANSYS finite element The analysis software successfully established the finite element model of the grid structure, among which the link8 element in ANSYS is used as the member element.

(2) The ANSYS modal analysis algorithm of the free vibration frequency of the grid structure is given, and the realization process of the modal analysis is explained. The finite element analysis model of a variety of grids is established in the form of command flow. Through the analysis of the free vibration frequency of these grids, the general law of the free vibration of the grid is obtained, and the influencing factors of the free vibration frequency of the grid are determined. The effects of different loads, boundary conditions and different spans on the natural vibration period of the grid structure are studied.

(3) Explains the steps of spectrum analysis using ANSYS software. Using the mode decomposition response spectrum method, using ANSYS software to study the seismic action of three different span grids, the distribution law of the seismic internal force of the grid structure is obtained, and the influence of the horizontal seismic action on the roof grid is compared and analyzed. At the same time, the influence of different spans on the distribution law of earthquake internal forces is also investigated.

(4) Using time history analysis method and using finite element model to study the nonlinear performance of the grid structure. The nonlinear dynamic response law of the grid structure is analyzed, and the linear and nonlinear calculation results are compared and analyzed. At the same time, the seismic response results when different seismic waves are selected are compared and analyzed.