| Under the background of the rapid development of the storage industry,the drive-in racks with high space utilization and easy mechanized operation are especially favored.However,when the drive-in racks are used for the planting racks of the plant factory,that will be in the long-term wet and corrosive environment,the use of steel racks,which are common in the market,would affect the durability of the structure,while racks made of aluminum can be better suitable for such environments.So far,domestic research on the structural performance of drive-in racks is immature,and the study of aluminium alloy rack structures are even rarer.In order to meet the realistic needs of plant factory construction,this dissertation mainly adopts the method of finite element simulation and carries out multi-scale and all-round research on the structural properties of the drive-in aluminum alloy racks according to the research ideas from joints to whole structure and from static analysis to dynamic analysis.The main research contents and results are as follows:The solid models of the column base joint,beam-column joint and column top joint of the drive-in aluminum alloy racks are established,and the joint stiffness of the three types of rack joints is studied by using the displacement loading method.It is found that the joint stiffness of these three joints show obvious nonlinearity;through the parametric analysis of the three joints,the degree of influence of the installation allowance of the joints and different bolt arrangements on the joint stiffness is determined.According to the racks’ structural characteristics,a simplified analysis on the columns is carried out.And the first-order elastic analysis method is used to analyze the effective length factor of the rack columns in the direction of the vertical cargo aisle,and the values of the effective length factor of the variable axial force rack columns are given by combining theoretical analysis and finite element simulation,as well as the formula and table of the effective length factor of the variable axial force columns considering the elastic support at the column end.The direct analysis method is used to analyse the law of the influence of non-linear factors and initial defects on the stable load carrying capacity of rack columns.Establish a fine overall analysis model,and the dynamic response and collapse resistance of the rack structure when it is hit by a forklift are analyzed by the dynamic analysis method.Through the analysis of typical working conditions,the most unfavorable parts and damage forms of the racks structure are determined,and through the collapse analysis on this basis,it is found that the racks structure has better resistance to continuous collapse.The influence law of each impact factor on the dynamic response of the racks structure is obtained through parametric analysis.And some anti-collapse measures that can effectively control the dynamic response of the rack structure are given.The dynamic response of the racks when subjected to frequent earthquakes and rare earthquakes is analyzed by using the time-history analysis method.It is found that the seismic response of the drive-in aluminum alloy rack structures when subjected to earthquake is greater along the vertical cargo channel than along the cargo channel;the shear force at the bottom of the columns is smaller and the displacement at the top of the columns is larger;finally,some measures that can effectively control the seismic response of the rack structures are given. |
PDF Full Text Request