Analysis And Simulation Of Cushioning Characteristics Of Cylindrical Air Cushion For Cushioning Packaging

Air cushion materials have been widely used in the field of cushioning packaging in recent years,which are one of the emerging packaging materials.It has the characteristics of light weight,excellent sealing,environmental protection,and good load-bearing performance,and it occupies an important position in the design of cushioning packaging.Since the design and selection of air cushion packaging mostly relies on experience,there is very little theoretical research on the deformation process of air cushion under load.There is no qualitative index to characterize its cushioning characteristics,and there are also difficulties in simulation research.Therefore,this subject takes the most common cylindrical air cushion as the research object,and conducts research from three aspects:basic theory,experiment,and simulation.The main research contents and conclusions completed are as follows:(1)Research on the theoretical model of air cushion.Research the cushioning mechanism and function conversion principle of the deformation of the air cushion under external load,and apply the theory to the air cushion.The study found that the geometric characteristics of the compression deformation of the previous geometric compression theory model of the air cushion were deviated,so the geometric model was improved,and the relationship between the compression load and the amount of compression was derived from the ideal gas equation.The influence of factors such as initial inflation pressure,compression amount,and initial width of the air cushion on the cushioning performance of the air cushion is studied.The relationship between the internal energy,work and heat of the air cushion in a confined space is studied by using the theoretical model of thermodynamics.An important index to characterize the cushioning performance of the air cushion is given,that is,the stiffness model related to the air cushion inflation pressure,geometric parameters,and variability index.According to the drop impact model,the energy conversion and loss caused by the free fall of the air cushion at a fixed height are studied,and the relationship between elastic deformation energy,reflected energy,and damping is obtained.The results show that the cushioning performance of the air cushion and the elastic deformation energy and emission Energy is closely related.(2)Experimental research on cushioning characteristics of air cushions.For the air cushion,film tensile test,quasi-static compression test,and dynamic compression test are mainly done to study its cushioning characteristics.Tensile tests on air cushion films of different thicknesses showed that the maximum difference in yield stress values of air cushion films with different film thicknesses is 9%,the maximum deviation of plastic strain values is 15%,the elastic phase is shorter,and the plastic phase time is very long.Comparing the load-displacement curve obtained from the quasi-static compression test with the theoretically derived formula curve,the results showed that the trends of the two are basically the same.The quasi-static test results showed that the larger the width of the air cushion is,the more energy it absorbs.Within the range of reasonable inflation strength,the greater the pressure,the better the cushioning performance.The dynamic compression test results showed that the thicker the film thickness of the air cushion is the smaller the maximum acceleration when subjected to impact,the larger the width of the air cushion is,the better the bearing performance,the inflation pressure has less effect on the cushioning performance,and the maximum acceleration increases with the height of the drop increase.(3)Simulation study on cushioning characteristics of air cushion.The ABAQUS finite element software was used to simulate the deformation process of the air cushion under dynamic compression load.In the simulation research of air cushion,there are difficult problems such as geometric nonlinearity,material nonlinearity,contact nonlinearity,fluid-structure interaction and so on.Since the Eulerian-Lagrangian method is used to study the cushion characteristics of air cushions to simulate the fluid-solid coupling problem,this paper proposes to use the Eulerian-Lagrangian method to simulate the entire deformation process,which is different from the simulation of the fluid cavity method.The results are compared,and the reaction force and displacement values of the two single nodes are selected for comparison.The simulation results showed that the simulation results of the Eulerian-Lagrangian method and the fluid cavity method are very close,which also verifies the Eulerian-Lagrangian method is feasible.In summary,the basic theoretical research of air cushions can provide design guidance to manufacturers;experimental research can determine the parameters of air cushions based on products;simulation research can reduce instability factors caused by actual tests,save manpower and material resources,and have certain economic applicability.