Lateral Pressure Experimental And Finite Element Analysis Of Steel Silo Under Earthquake

The application of storage structure was increasingly widely used.During the operation of silos,the force of bulk storage on the silo is a significant cause of silo damage.Especially,the interaction between storage material and silo made the mechanical behavior of the structural system more complex under earthquake,which is more likely to cause the damage or failure of the silo structure.At present,the mechanical behavior between grain particles and the interaction mechanism between storage and silo structure are still uncertain,and the influence of their interaction on the seismic performance of steel silo is not completely clear.Based on this situation,taking the grain bulk steel silo structure as the research object.This paper studied the lateral pressure of grain bulk-steel silo structure and the stress characteristics under earthquake by shaking table test and finite element method.The main research contents and results were as follows:(1)The shaking table test of grain bulk-steel silo model was designed and implemented.Taking the lateral pressure of silo wall and the circumferential strain of the silo as the test objects.Formulated test conditions and specific test schemes,selected artificial wave,ElCentro wave and Taft wave for excitation,and arranged pressure sensors and strain gauge measuring points.The dynamic analysis of grain bulk-steel silo structure model under multiple working conditions was carried out.(2)The experimental phenomena and seismic response law of steel silo under different grain types,different grain filling heights,different seismic waves and input peak ground acceleration were compared.The distribution trend of static and dynamic lateral pressure and overpressure distribution area of grain bulk-steel silo model structure were analyzed.The results showed that the relative dynamic lateral pressure of soybean and wheat increased with the rise of peak ground acceleration.The maximum of storage material with the half and full filling condition occurred in the upper part of storage material.Different grain storage materials had different material characteristics,and the dynamic lateral pressure distribution of was also different.At the same filling height,the dynamic lateral pressure of wheat storage materials was significantly greater than that of soybean storage materials.The maximum overpressure of the model occurred at the top of the silo model.(3)The variation laws of circumferential strain and wall stress of steel silo wall in empty,half and full filling condition under earthquake are compared.The results showed that the silo wall bore high wall stress due to the filling of storage materials.The increase or decrease of stress at each measuring point also indicated the asymmetry of silo pressure response.The maximum stress of silo wall under earthquake was concentrated in the middle and lower part of silo.The lower part of the silo was at the critical position where the storage material moved relative to the silo wall.The storage material changed from solid state to flow state,and it was easy to form a stiffness mutation,resulting in silo failure.(4)Based on the relationship between the damping ratio,dynamic shear modulus and dynamic shear strain of soybean bulk under dynamic load obtained from dynamic triaxial test,the deformation and mechanical characteristics of grain bulk under dynamic load were analyzed,and the equivalent linear model of soybean bulk was established.The finite element analysis model of grain bulk material steel silo structure was established by ANSYS finite element program.The finite element calculation results of steel silo under static state and seismic excitation were compared with the experimental results.The results showed that the calculation results of static lateral pressure on the top of silo were close to the Chinese code and the Janssen theory,and the simulation results were in good agreement with pressure distribution predicted by the Chinese code.The finite element calculation results of dynamic lateral pressure of storage materials gradually decreased along the height of silo wall,and the distribution trend of dynamic lateral pressure was in good agreement with the experimental results.