Deformation And Energy Absorption Of Aluminum Foam Sandwich Tube Under Different Constraints

Cellular material,as a new engineering material,has the advantages of low density,high specific energy absorption and strong impact resistance,as well as a variety of excellent physical properties such as high damping performance,good fluidity and filtration separation performance,ideal acoustic thermal and electromagnetic properties.It has more and more extensive applications in the technical fields of noise reduction,separation engineering,catalytic support,explosion protection,energy absorption and buffering.The sandwich structure formed by using it as a core layer material is widely used in various collision energy buffer systems such as aerospace,automobiles,ships,and engineering protection due to its high specific strength,high specific stiffness,and good impact resistance.With the rapid development of science and technology,people have put forward higher requirements for the crashworthiness of structures.As a buffer energy-absorbing structural element in practical engineering applications,it not only has to withstand various types of impact loads,but also needs to be placed under different external constraints.Therefore,in this paper,the foamed aluminum sandwich double circular tube structure is taken as the research object,considers four different external constraints,the dynamic response of sandwich tube under lateral impact load and explosive load are studied.The main work is as follows:(1)The finite element software LS-DYNA is used to establish the finite element model of aluminum foam sandwich tube under unconstrained,inclined constraint,sidewall constraint and combined constraint.The deformation rule and energy absorption performance of sandwich tube under lateral impact load and explosion load are studied.(2)The effects of the diameter and thickness of the inner and outer tubes,the relative density of aluminum foam and the impact velocity on the deformation and energy absorption performance of aluminum foam sandwich tube in different constraint systems under lateral impact load are studied.The results show that with the decrease of the diameter of the inner tube,the increase of the wall thickness of the outer tube,the increase of the impact velocity and the relative density of the aluminum foam core,the impact load and specific energy absorption of the sandwich tube are increased;The increase of the thickness of the inner tube and the diameter of the outer tube increase the specific energy absorption of the aluminum foam sandwich tube with unconstrained and inclined constraint,and has no obvious effect on the energy absorption of the sandwich tube under the sidewall constraint and combined constraint;When the constraint system is from unconstrained,inclined constraint,sidewall constraint to combined constraint,the impact load and specific energy absorption of the sandwich tube increase;When the impact velocity is 10 m/s,the deformation mode of the sandwich tube in unconstrained system is up-down,left-right symmetry,and other systems are symmetrical left and right.With the impact velocity up to 50 m/s,the deformation mode of the sandwich tube in the four systems becomes left and right symmetry mode.(3)The effects of the diameter and thickness of the inner tube,the relative density of aluminum foam and the quality of TNT on the blast resistance of aluminum foam sandwich tubes in different constraint systems under lateral explosive load are studied.Under the condition of equal quality of TNT,with the increase of diameter of inner tube,the decrease of wall thickness of inner tube and the decrease of relative density of aluminum foam,the displacement of center point of upper part of inner and outer tube of aluminum foam sandwich tube in the four constraint systems increases.The larger the TNT quality is,the greater the center point of displacement of the inner and outer tube of the aluminum foam sandwich tube in the four constraint systems;The constraint system is from unconstrained,inclined constraint,sidewall constraint to combined constraint,the deformation resistance of the aluminum foam sandwich tube is increased,and the center point of displacement of the inner and outer tube decreases.