Experimental Study On Stability Of Prefabricated Corrugated Steel Silo Under Loading Of Grain

The prefabricated steel silos are widely used for bulk storage in agriculture,mining,electric power and other fields due to their advantages of light weight,low foundation requirements,simple assembly and detachability.Their walls mainly include profiled steel plates and vertical stiffener.Profiled steel plates mostly use corrugated plates with thin wall thickness to reduce the structural weight.Large-diameter silos and deep silos need to be equipped with stiffeners to improve the silo’s carrying capacity.Due to the complicated stress and force transmission path of the steel plate silo with stiffeners and corrugated walls,its stability design is the difficulty and focus of structural design.China’s "Code for Design of Grain Steel Silos"(GB 50322-2011)on steel plate silos with stiffeners,the simplified method of strength calculation when the silo wall is corrugated steel plate is: the vertical pressure borne by the silo wall is not calculated,and all the vertical pressure is borne by the stiffener.This provision can not truly reflect the bearing capacity of this type of structure.In order to explore the actual mechanical performance of the prefabricated corrugated steel silo and whether the vertical stiffeners are unstable or not under load,this paper uses bulk wheat to carry out the stability test of steel silo model under load step by step,and uses ABAQUS general finite element program to carry out finite element simulation.The main work is as follows:(1)Referring to the actual engineering diameter thickness ratio,considering the supporting effect of corrugated plate and vertical stiffener,and the load boundary conditions of the actual silo,combined with the "Code for Design of Grain Steel Silos",the size and specification of the test model for strength and stability design of the prefabricated corrugated steel silo are preliminarily determined,make and install the test model of the prefabricated corrugated steel silo.(2)After the installation of the test model is completed,a laser scanner is used to quickly,accurately,and contactlessly measure the initial geometric dimension of the cylindrical shell of the corrugated warehouse wall part of the test model,so as to obtain the point cloud data of the actual initial geometric dimension of the test model,and the reverse modeling is carried out to obtain the actual initial dimensions of the test model.(3)The model of initial geometric defects of actual steel silos obtained by reverse modeling is imported into ABAQUS general finite element program.Considering the double nonlinearity of geometry and materials,a finite element simulation is carried out to provide reference for the determination of characteristic points of subsequent tests.The supporting reaction force and vertical displacement of stiffener are extracted,the load-vertical displacement curve of stiffener is drawn,and the stress and displacement of test characteristic points at different grain loading heights are extracted,providing theoretical data for comparative analysis with test data.(4)The stability test of the steel silo model under the grain load is carried out.The wheat is selected as the storage material and loaded into the test model step by step.The stress and deformation of the characteristic points of the test model under different grain loading heights are obtained.According to the stress value measured at the bottom characteristic point of the stiffener,the axial force of the stiffener under different loading height is calculated,the load vertical displacement curve of the stiffener is drawn,and some test results are compared with the results of finite element simulation.The results show that the vertical stiffeners designed and selected according to the code will not be destabilized and destroyed under the load of grain,but the cross-sectional shape will change,showing a distorted buckling mode.