Numerical Simulation And Experimental Research On Vibration Process Of EPE Cushioning Material

In the process of transportation,packaging will produce physical events such as vibration due to transportation tools,especially when resonance occurs,which will seriously affect the protection performance of packaging.Foamed polyethylene(EPE)is widely used in vibration isolation packaging of electronic products,medical equipment,household appliances,precision instruments and glass porcelain products due to its light weight,strong energy absorption capacity and strong resilience.In this paper,EPE is taken as the research object,and the effects of ambient temperature,EPE thickness,EPE area and static load on the vibration characteristics of EPE are studied through static compression test,sinusoidal sweep vibration test and finite element analysis.The specific contents are as follows:(1)Using static compression experiments,the compressive stress-strain curves of EPE at different ambient temperatures(-20 ℃、0 ℃、20 ℃、40 ℃、60 ℃)were obtained,and the elastic modulus of EPE at different temperatures was obtained by calculation,It is used for the definition of finite element material properties and establishes an evaluation equation for the change of elastic modulus of EPE with temperature.(2)The sine frequency sweep vibration experiment was used to obtain different ambient temperatures(-20 ℃,0 ℃,20 ℃,40 ℃,60 ℃),different EPE thicknesses(20 mm,40 mm,50 mm,60 mm,80 mm),100 mm),different EPE areas(100?100 mm,120?120 mm,150?150 mm,170?170 mm,200?200 mm)and different static loads(1.16 kg,2 kg,3.76 kg,5 kg),6.16 kg),the response acceleration-frequency value of the vibration isolation system is converted into a vibration transmissibility-frequency curve,and the resonance frequency,maximum vibration transmissibility and damping ratio under the corresponding conditions are determined;The variation law of EPE area and static load;the temperature term coupling is carried out on the existing natural frequency analytical formula of the vibration isolation system,and the verification is carried out.(3)Based on the static compression and sine sweep vibration experiments,the elastic modulus and damping ratio of EPE are obtained,and the finite element model is established.The vibration transfer rate-frequency curves of different ambient temperature,EPE thickness,EPE area and static load are compared to verify the accuracy of the model.The effects of elastic modulus and damping ratio of EPE on the resonance frequency and maximum vibration transmission rate of the system are analyzed.Based on the experiment,the finite element analysis is used to analyze the vibration isolation packaging of the existing notebook computer,and the structure optimization is carried out with the frequency target.