| Today, with quickly developed of economy, large steel silos were quickly developed and gradually used in a lot of fields, such as light industry, metallurgy, electric power, coal, building materials, food and so on. So far, domestic and foreign scholars made a large number of studies about silo structures, which can be attributed to the following two main directions: one is the horizontal lateral pressure acted by stored bulk solid on silo walls; the other is research about seismic performance of silo structures.Based on the former research theory, this paper uses the general finite element analysis software ANSYS to analyse an actual project and research the safety and seismic performance of large steel silo structures.In the research, there were two kinds of models,one was empty silo, another is full silo. When building and analysis of these models, loads considered in conventional design of large steel silo structures are taken into account here, including the structure gravity, the stored bulk solid’s horizontal lateral pressure and vertical frictional force on silo’s walls, wind load, snow load and horizontal earthquake action. And the analytical methods used in the paper included static analysis, buckling analysis, modal analysis, spectrum analysis and the time history analysis, etc.In the research, The first chapter covered the background of this paper’s work. As China’s cement industry boomed quickly, more and more large cement mill were built one by one,. So cement production was greatly enhanced, at the same time, the wide application of large steel silos was put on the agenda. But As a type of thin-walled shells of revolution, the structure behavior and failure criteria of large steel silos are very complex, this caused that it’s damage rate could’t be ignored in the actual application. The second chapter included building the finite element model and static analysis, and the latter was to study the stress state of structure influenced by material load compared to other loads, and the most unfavorable position under the static loadings. In the third chapter, the buckling analysis was to study the stability of structure, in order to prevent the occurrence of unstable failure, and gave the scope of easy unstability of the structure. In the forth chapter, modal analysis is used to study the structure’s dynamic characteristics, including the natural vibration frequency, cycle and vibration model. In the fifth and sixth chapters the spectrum analysis and time history analysis were adopted to study the seismic performance of two models (fullfilled and unfilled silos) under two diferent seismic performance (7and8degrees), and the data included horizontal displacement, vertical stress, Mises stress and the structure force. The spectrum analysis was the single point response spectrum analysis, and only elcentrol wave was considered in the time history analysis. Besides, compared the data from spectrum analysis and the data from the analysis acluding <code for design of grain steel silos>(GB50322-2001),it proved that the former was40%-60%of the latter. At the same time, compared the data from spectrum analysis and the data from time history analysis, the former was higher than the latter. So, the result from the analysis acluding code leans conservative.Through the researcher about the characters of static and dynamic, stability and seismic performance,this paper hopes to provide advice and basis for the design of large steel silos. |
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