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Analysis of natural vibration characteristics and seismic response of space frame structures

Space frame structure is a good form of long span roof structure. It has the advantages of space force, saving steel, large space stiffness, small building height, convenient industrialization, standardization, beautiful building shape and so on. With the development of economy and the continuous progress of science and technology, the application of spatial framework in architecture is increasingly perfect. However, due to the frequent occurrence of natural disasters such as earthquakes year by year, how to carry out the seismic design of space frame structures has become an important issue of concern to people, so it has certain practical significance for the seismic response research of space frame structures, and the conclusions can be used for reference in engineering practice.
The analysis of natural vibration characteristics and seismic response of space frame structure consists of the following parts:

(1) The general principle of finite element theory, the function 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 space frame are given. The finite element model of space frame structure is successfully established by using ANSYS finite element analysis software link8 unit in NSYS.

(2) The ANSYS modal analysis algorithm of free vibration frequency of space frame structure is given, and the realization process of modal analysis is expounded. The finite element analysis models of various spatial frames are established in the form of command flow. By analyzing the free vibration frequency of these spatial frames, the general law of free vibration of spatial frames is obtained, the influencing factors of free vibration frequency of spatial frames are determined, and the influences of different loads, boundary conditions and spans on the free vibration period of spatial frames are studied.

(3) Describes the steps of spectrum analysis by ANSYS software. The seismic action of three space frames with different spans is studied by using the response spectrum method of mode decomposition and ANSYS software, and the distribution law of the seismic internal forces of the space frame structure is obtained. The influence of horizontal earthquake action on the roof space frame is compared and analyzed, and the influence of different spans on the distribution law of the seismic internal forces is also investigated.

(4) The nonlinear performance of space frame structure is studied by using finite element model and time history analysis method. The nonlinear dynamic response law of space frame structure is analyzed, and the linear and nonlinear calculation results are compared. At the same time, the seismic response results of different seismic waves are compared and analyzed。