| Foundation as the supporting components of large steam turbo-generator set,carrying all kinds of loads generated in operation,its dynamic characteristics directly impacted on security and economy of power plant operation.Although a lot of research work has been done in the field of study on dynamic characteristics of foundation,there are many theoretical and technical problems to be overcome.The dynamic response of large steam turbo-generator set foundation was complex,because the equipment of steam turbine generator set had an influence on foundation.The study on separated foundation of steam turbine generator set already couldn't satisfy the needs of solving the problems of the foundation.Therefore,it was of great engineering value to study the dynamic characteristics of the foundation and the coupling dynamic characteristics of the shaft system.In this dissertation,two kinds of method,field test and finite element analysis,were used to study the dynamic characteristics of steam turbine generator set foundation.With the needs of actual project,the study of seismic performance of foundation and coupling dynamic characteristics of shaft with foundation should be well completed.Firstly,the three-dimensional model of foundation and base plate was constructed by software Solidworks.And the finite element model of foundation and base plate was established by using the large-scale finite element analysis software Algor.It was need to analyze the influence of the natural frequency of foundation covering with equipment quality.And it also need to calculate the dynamic characteristic parameters of a pure framed foundation by comparison.It was found that equipment quality on the foundation had an influence on the natural frequencies and the base plate of foundation so on.Then,the typical seismic waves,such as EL-centro wave and Tianjin wave,were imported into the software Algor to conduct the seismic response spectrum analysis of foundation.El-centro wave was guided into the software ANSYS to establish the seismic time history response analysis model.Response of displacement and stress could be derived from the result of calculation of the two models.The displacement response and stress response of the operating platform of foundation by calculation results showed were severe,and the stress concentration was obviously detected in the connection of beam and column.Finally,the three-dimensional solid model of foundation-shaft system was established by using Solidworks,then it was imported into Algor to establish the finite element model of foundation coupled with shaft system.The calculation results showed that the natural frequency of the coupled model was significantly different from the base frequency of foundation,and the design of dynamic characteristics of foundation was different from actual foundation.Importing seismic wave,EL-centro wave,into software as excitation,the result of calculation coupling model showed that the shaft deformation was obvious and bearing stress concentration was obvious.As a result,it was easy to happen dynamic and static parts rubbed. |
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