Research On Cushioning Properties Of EPE

In the course of the circulation of commodities, external shocks, vibration and other environmental products will cause some damage. If force is larger than the limitation of product, it is very prone to damage. During the logistics process, contents damage or not are determined by not only external environment (such as drop height, ambient temperature, etc.). but also the property of cushioning material (eg, material, density, thickness, etc.) and the fragility of product itself. Therefore, from the perspective absorbing energy, combining the external factors and material properties will be more intuitive to achieve the purpose of protecting products. Expanded Polyethylene (EPE with apparent desity of 17.50kg/m3) was chosen in this research, through the dynamic impact experiments at different temperature, thickness, impact height, and dynamic cushioning property of this type of density of the material were studied.Based on dynamic impact test in different temperature environments (60℃,40℃ 23℃,0 ℃.-15℃ and -30 ℃) of EPE, "maximum acceleration-static stress" curves could be compared visually at high temperature, room temperature and low temperature. Experiment results show that the high and low temperatures will certainly change EPE material properties, when the static stress is less than 3kPa, EPE dynamic cushioning performance at low temperature environment is worse than room temperature, the maximum gap even could reach 22g; when static stress is higher than 3kPa, cushioning performance at low temperature will be better. Besides, during the whole static stress scope, high temperature will cause the material softening, thus reducing its buffering capacity. By fitting the quadratic curve, we establish the relationship between maximum acceleration and static stress in different temperatures, so that we could provide a theoretical reference for transport logistics packaging design in different temperature environments.Laser distance sensor was used to obtain dynamic deformation of EPE during impact tests to the samples synchronized with acceleration recording. Analyzing and establishing the relationship on the dynamic deformation of materials, the absorption of energy, the thickness of material, the height of shock and the maximum acceleration. Analyze the relationship between the maximum acceleration and static stress of material from the perspective of the energy absorption of material hips in determining. Estimate the dynamic buffer curve of any thickness EPE at a certain height. Make the anticipation for the carrying capacity of the different thickness material with fewer experiments. Trying to establish the relationship between the static stress of material and the maximum acceleration at a certaion materail thickness and any height of shocking. This laved a foundation for estimating dynamic cushioning properties and related strains of EPE in any drop height, thus vastly raised the test efficiency.