Study On The Seismic Response Of Concrete Silo Considering The Impact Of Storage Material

With the rapid development of industry and agriculture in China,silos have been the main method for the storage of industrial products and agricultural goods.The stability structure design of the silos has faced a new challenge since more and more silos have been put into use all over China.Earthquake is one of the major causes to silo collapse,and China is a country with frequent earthquakes,as shown in the previous seismic database,earthquakes of magnitude 7 or above can lead to shaking,cracking,inclination,or even collapse of silos within the seismic area,which indicates that seismic design of silos in China becomes an urgent issue.The interaction between silos and storage material during the earthquake still remains unclear.Thus,a systematic study on the aseismic of silos and storage together with aseimic design has significant importance and implementation possibility in the near future.In this thesis,the silo and stored material were considered as a system structure altogether,and the interactions between silos and stored material under seismic conditions were analyzed and calculated by adopting finite element method.Based on the systematic analysis of the structure characteristics of the silo,earthquake damage characteristics and damage mechanism of silo,the smooth particle hydrodynamics method(SPH method)was introduced,the bulk material was considered as equivalent to smooth particles for calculation and analysis.The factors of geometric nonlinearity,dynamic elastic modulus and damping were taken into consideration,and the nonlinear vibration differential equations of the model were established based on the thin-walled cylindrical shell theory and SPH,the boundary conditions and the solution method were determined by Galerkin method.A simulated seismic shaking table test was carried out by using the equivalent material of storage material and silo.The model characteristics,acceleration,displacement,strain,shocking force and damping response of the storage material-silo interaction model under different amount of storage material,particle size and flow conditions were studied by the hierarchical loading method.Moreover,the finite element software ANSYS/LS-DYNA3D was adopted to establish a finite element model of silos-material-foundation interaction system,the effect of different site category,material parameters and the silo size on the system response was investigated and evaluated by comparing with SPH algorithm can effectively simulate the storage material of silos which will provide a useful reference for engineering application.Basic characteristics and damping mechanism of the structure isolation system were analyzed to reduce the adverse effect of earthquake on the silo system.The rubber isolation pad was selected as the isolation material,modal analysis and displacement of the non-isolation silo system and the isolation silo system were analyzed by ANSYS/LS-DYNA3D software respectively.The results show that the rubber isolation material can effectively absording the earthquake energy on the silo system.The application of seismic isolation material has been applied to seismic isolation projects and achieved good isolation effect.Study method and isolation materials proposed in this paper can be used for future silo seismic design and construction.