Mechanical Behaviors Of Honeycomb Paperboard Under Dynamic Impact Loadings

Honeycomb paperboard is a new type of environmentally friendly cushioning packaging material,it has drawn the extensive attention in many fields.It has not only a novel structure,but also strong advantages in bearing,cushioning,and heat insulation properties.It also uses less material and is light in weight.At present,it is widely used in many fields such as packaging,furniture and building materials.Therefore,it is of great scientific research value to study the out-of-plane dynamic impact mechanical properties of honeycomb paperboard.This thesis mainly studies the influence of thickness,entrapped air and thickness to length ratio on the out-of-plane dynamic impact mechanical properties of honeycomb paperboard by dynamic impact test.The main research work and results are as follows:(1)The elastic modulus and yield strength of the honeycomb paper are tested,which is the experimental basis of the thesis.On the basis of the theoretical analysis of honeycomb paperboard,the influence of thickness,entrapped air,the percentage of holes and thickness to length ratio on the out-of-plane impact properties of the honeycomb paperboard are analyzed.The relevant theoretical formula are given to provide theoretical basis for experimental study.(2)The influence of thickness on the out-of-plane dynamic mechanical properties of honeycomb paperboard with different thickness is studied when the thicknesses are 30,40,50 and 60 mm,respectively.The effect of thickness on contact force,maximum contact force,maximum displacement,maximum strain and absorption energy are explored through the dynamic impact experiment and analysis.In conclusion,the contact force gradually decreases and the contact duration gradually increases with the increase of honeycomb paperboard's thickness for the given impact energy.When the impact energy per unit thickness is specified,maximum displacement and absorption energy will increase as the thickness increase while contact force,maximum contact force and maximum strain will decrease as the thickness increase;for the honeycomb paperboard of any thickness,the maximum contact force,maximum displacement,maximum strain,absorption energy will increase as the impact energy of unit thickness increases.For the same impact energy,the absorption energy of honeycomb paperboard with the different thicknesses is nearly constant,and the impact energy is linear with the absorption energy.As a result,the absorption energy capacity of honeycomb paperboard,only being dependent upon the degree of impact energy,is nothing to do with its thickness.(3)The influence of entrapped air on the out-of-plane dynamic mechanical properties of honeycomb paperboard with different percentage of holes is studied when the percentage of holes are 0%,50% and 100%,respectively.The effect of percentage of holes contact force,maximum contact force,maximum displacement,maximum strain and absorption energy are explored through the dynamic impact experiment and analysis.It is concluded that for the specified impact energy,the maximum contact force and absorption energy decrease,the maximum displacement and maximum strain increase as the percentage of holes increases while for the given percentage of holes,the maximum contact force,maximum displacement and maximum strain as well as the maximum absorption energy increase just as the impact energy increases.In addition,the higher impact energy is,the shorter time of running up to the maximum contact force is,and the longer contact duration results in.In the dynamic impact test,the ability of absorbing impact energy of honeycomb paperboard is obviously enhanced by the entrapped air,and for the given impact energy of honeycomb paperboard,it is concluded that the higher percentages of holes will be able to cause the paperboard to be more readily compressed and the less energy to be absorbed.(4)The influence of thickness to length ratio on the out-of-plane dynamic mechanical properties of honeycomb paperboard with different thickness to length ratio is studied when the thickness to length ratio are 0.028 and 0.03,respectively.The effect of thickness to length ratio on contact force,maximum contact force,maximum displacement,maximum strain and absorption energy are explored through the dynamic impact experiment and analysis.In conclusion,when the impact energy is constant,the larger thickness to length ratio is,the smaller the maximum displacement and the maximum strain are and the larger the maximum contact force and absorption energy are.In the dynamic impact test,the ability of absorbing impact energy of honeycomb paperboard is obviously enhanced as the thickness to length ratio is increased.It is conclude that when honeycomb paperboard is used as the cushion material,the influence of the entrapped air on the impact properties of the honeycomb paperboard can not be ignored.The appropriate thickness and thickness to length ratio are selected according to the actual situation to avoid excessive packaging.This study will well contribute to the further theoretical exploration and practical application of honeycomb paperboards.