Analysis And Software Development Of Shuttle Racks Based On Substructure Method

The pallet shuttle steel racks is a common kind of steel-rack,and it belongs to the component-intensive cold-formed thin-wall plug-in structure.With the rapid development of China’s logistics industry in recent years,the demand for warehousing capacity has surged,and the scale of steel-rack projects has become larger and larger.The total number of members of the project often reaches hundreds of thousands,which leads to many difficulties of structure modeling and design work,but there are no related design software about pallet shuttle racks at China or abroad.On the other hand,China’s research on the racks field is relatively late,and the rack-related codes have not been updated for a long time.There are no clear standard for many aspects of steel-rack design,and various types of safety accidents caused by steel racks have occurred frequently.Therefore,in view of the status before,this paper focusing on the actual difficulties in the research of shuttle rack design,compiles the Abaqus-based shuttle shelf modeling analysis program,and attempts to introduce the substructure method to solve the problem of large analyze model calculation efficiency.This paper first introduces the add-on functions development of Abaqus based on Python language,as well as the structural form,load function and analysis method of multi-layer pallet shuttle steel-rack,and explains the use of multi-layer pallet shuttle steel-rack design software in detail with the program GUI.The use-method and main features are verified by examples.Then,the substructure method is introduced in this paper.Five schemes of shuttle rack sub-structure method are proposed,and their computational efficiency is compared under different conditions,scales,grid sizes,etc.,and the recommended scheme of shelf substructure is given.Finally,the software is used to study the mechanical properties of multi-layer pallet shuttle steel-rack in different beam-column joint stiffness,column foot joint stiffness and seismic conditions,and summarize the rules,and then add preliminary component section selection function in the program,which can give the engineering practical a certain degree of guidance.The main findings of this paper are as follows:(1)An shuttle racks analysis software based on Abaqus in Python language with GUI user interface was compiled.And combined with specific examples,the software calculation results are compared with the Sap2000 analysis results to prove the correctness of the analysis result.The results come to be very close.(2)Propose five sub-structure schemes for pallet shuttle racks,and compare the calculation efficiency of them.It demonstrates that the appropriate sub-structure scheme can effectively improve the calculation efficiency of the model.When the number of units is about 50,000,the efficiency of linear analysis can increase by 53.8%,and the efficiency of nonlinear analysis can be increased by 67.9%.(3)For conventional medium-height pallet shuttle racks,when linear analysis is performed and the number of columns is more than four times the number of rows,or when nonlinear analysis is performed and the number of columns is seven times or more of the number of rows,it is recommended to use the scheme 2 in the paper for calculation,and vice versa should use scheme 3 for calculation.(4)The stiffness of beam-column joints and column-foot joints have a significant impact on the capacity of the column and beam.The increase of the stiffness of the two joints can both improve the lateral resistance of the structure and the former has better effect than the latter.And the appropriate stiffness of beam-column joint and column-foot joint are given.(5)According to the characteristics of the shuttle racks structure system,the shuttle racks column,beam and railways sections selection function based on genetic algorithm are added into the program,and the correctness and stability are verified by an example.