| Paper tube is an excellent energy absorption structure,characterized by light weight,low cost,easy processing and environmental friendliness.At the same time,they have stable crushing load and long crushing stroke under axial load.Compared with thin-walled metal tube,paper tube in transport packaging,product protection and other fields has a wider range of application.However,the paper tube crushing behavior and dynamics research is lack at present.Therefore,it is of great academic significance and engineering value to study the energy absorption mechanism and performance of the crushing deformation mechanism of paper tube under axial compression and impact load.In this paper,the energy absorption characteristics of square and circular paper tubes under axial quasi-static compression and medium-low speed impact are studied.Through the test and theoretical analysis method,the deformation mechanism and the energy absorption mechanism of the paper tube under axial compression and impact load are revealed,the influence factors of energy absorption performance are discussed,and the energy absorption theoretical prediction models of paper tube under axial compression and impact are established.The research contents and conclusions mainly include:（1）Test and characterization of mechanical properties and strain rate dependence of paper adhesive laminate（PAL）materials.The tensile and compression mechanical properties of the two kinds of PAL materials were measured by quasi-static uniaxial tensile and compression tests.Through uniaxial tensile tests with strain rates ranging from 10-4 s-1 to 102 s-1,the mechanical properties of two kinds of PAL materials under different strain rates were obtained,and the strain rate correlation characterization model of PAL materials was established,which provided theoretical support for the study of energy absorption performance and prediction model of thin-walled paper tube under dynamic impact.（2）Study of energy absorption characteristics of square paper tube under axial compression.Based on the axial quasi-static compression tests of square paper tubes with different materials and specifications,the crushing characteristics,deformation mechanism and energy absorption mechanism of square paper tubes under axial compression were studied.The influence of factors on the energy absorption performance of square paper tubes was analyzed.A theoretical prediction model for the energy absorption performance of square paper tubes under axial compression was established,considering the asymmetry of tension and compression and effective crushing distances of paper tubes.The relative error between the theoretical prediction results and the test results is less than 14%,which proves the effectiveness of the model.The theoretical prediction model reflects the relationship between average crushing force and tensile yield strength,compression and tensile yield strength ratio,effective crushing distance ratio,tube wall thickness and tube side length.（3）Study of energy absorption characteristics of circular paper tube under axial compression.Based on the axial quasi-static compression tests of the circular tubes with different materials and specifications,the deformation mechanism and energy absorption mechanism of circular paper tubes under axial compression were studied.The influence of different factors on the energy absorption performance of the circular paper tube was analyzed,and the crushing deformation mode of the circular paper tube was obtained,which was different from the crushing mode of the metal tube.Based on the deformation model,a simplified spiral multi-lobe folding model of the circular paper tube was proposed,and a theoretical prediction model for the energy absorption performance of the circular paper tube under axial compression was established.The theoretical prediction model is a function reflecting the complex relationship between average crushing force and tensile yield strength,compression and tensile yield strength ratio,effective crushing distance ratio,tube diameter,wall thickness,tube length,winding angle and the number of spiral lobes.The model results are in good agreement with the test results.（4）Study of energy absorption characteristics of square and circular paper tubes under axial medium-low speed impact.The axial impact tests of the square and circular paper tubes were carried out in the initial impact velocity range of 2.4-4.6 m?s-1.The results show that the deformation mechanism of the square and circular paper tubes under the axial medium-low speed impact is the same as that under the quasi-static compression,and the axial crushing force presents an obvious strain rate dependence.Considering the strain rate dependence,theoretical prediction models for the energy absorption performance of the square paper tube and the circular paper tube under dynamic impact are established.The validity of the model was verified by impact test.Although the test results have a certain degree of dispersion,the model results still give a good prediction of the average value and the overall trend of the test results.For practical applications,this model can be used to evaluate the energy absorption performance of existing energy absorption structures,and provide theoretical guidence for the design of paper tube structures according to the known requirements for energy absorption performance. |
