Research On Mechanical Properties Of Pallet Based On Koch Fractal Structure

In the transportation and packaging industry,plastic pallets are reliable and durable,suitable for a variety of working conditions,and have a high degree of size standardization.At present,plastic pallets are gradually replacing wooden pallets,but there are few researches and optimized designs on the factors affecting the mechanical properties of pallets.Exploring pallet spacers with better mechanical properties and lower cost has more realistic significance for the development of plastic pallets.In this paper,aiming to to explore the factors affecting the mechanical properties of the Koch fractal structure and its application in the pallet block by the finite element method.Methods Based on the Koch fractal theory and referring to the national standard size of the tray,the Koch fractal structure model was established.Block samples were prepared by 3D printing technology using nylon 12 material.Firstly,on the basis of tensile and quasi-static compression experiments,a finite element model of PA12 plastic block was established and verified by static pressure experiments.The results show that the error between the finite element model and the experiment is 3.6%.On this basis,the effects of fractal order,height of the cushion block,and fractal wall thickness on the energy absorption performance of the cushion block are analyzed.Then use the multi-objective optimization module of ANSYS Workbench to perform sensitivity analysis,response surface analysis and response surface optimization on the height and fractal wall thickness of the block.The results show that the fractal order and the height of the spacer block have a great influence on the total deformation and stress,and the fractal wall thickness can be appropriately reduced,and the height can be increased to ensure the strength and reduce the quality.Taking the total deformation,stress-strain,etc.as the optimization goals,the stress is reduced by 79.0%,the total energy is reduced by 82.6%,and the mass is reduced by3.5%,and the enhanced block is realized when the fractal order is 2,the fractal wall thickness is 0.21 cm,the height of the block is 11 cm,.the mechanical properties and the goal of reducing the quality of the block.Comparing the optimized block with the common field-shaped block,the energy absorption per unit mass(SEA)is increased by 35.3%.Finally,the optimized block was substituted into the nine-foot plane pallet model,and the mechanical properties of the pallet under static load,dynamic load,drop and other working conditions were simulated and analyzed.The results show that the mechanical properties of the tray using the fractal spacer are improved by13%,and it meets the requirements of the national standard under static load,dynamic load,drop and other conditions.Thus,the goal of lightweight design of block is completed,and the result can provide new ideas for the lightweight design of plastic pallets.