Design And Optimization Of Pallet Rack

With the continuous development of the internet technology,the warehousing industry plays an increasingly important role in the logistics system.As a kind of storage equipment,pallet rack has simple structure and flexible set-up,which is widely used in storage field.Based on the finite element method,this paper analyses the influences on connections of beam-to-column joints,overall structure sizes and layout plans of members on mechanical properties of pallet rack.The numerical simulation of seismic performance of pallet rack is carried out in combination with different layouts of goods.The optimized design of rack structure is realized by using firefly algorithm,the main research contents are as follows:The finite element model of pallet rack is established,and mechanical differences among the complete rigid model,the complete hinged model and the semi-rigid model are studied.It is pointed out that the connection between beam-to-column joints has semi-rigid characteristics between complete rigid joints and complete hinge joints.The effects of the overall dimension parameters(the length of rack lattice,the width of rack lattice,the vertical distance between first beam and foot,the height of rack,etc.)and the layout plans of members(inclined supports,back members,top members,etc.)on mechanical properties are investigated.The results show that the longer the length of rack lattice is,the greater the maximum displacement and stress of the structure are.The influence of the width of rack lattice is weak,so it can be optimized first in the actual project.The higher the vertical distance between first beam and foot is,the lower the safety is.It is more prone to instability.The height of rack is the same.The layout plans of members obviously affect the structure,so it must be scientific and reasonable in the design phase.The seismic performance of pallet rack is analyzed by two methods: response spectrum analysis and time-history analysis.The results show that the longitudinal stiffness of the structure is weak,and the damage caused by longitudinal deformation is more likely to occur under earthquake excitation.When the loading of goods is lack of balance the seismic performance of the structure will also have different degrees of damage.In practical use,the layout of goods should follow this principle: first down and then up,left and right symmetry.The optimization model based on firefly algorithm and penalty function method is established to realize the lightweight design of pallet rack.The quality of the optimized structure is reduced by 8.2%,and the weight loss effect is obvious.The area of the optimized structure is reduced by 9.1%,and the warehouse capacity is improved.This model provides a practical method for the optimization design of the storage rack.