Research On The Axial Compression Stability Of Polyurethane Foam Filled Aluminum Alloy Tube

Aluminum alloys have been widely employed in civil engineering,especially in the field of long-span space,because of its light weight,high specific strength,corrosion resistance,and easy installation.However,due to its low elastic modulus,which is only one third of that of steel,the stability and deformation of aluminum alloy structures and components are more prominent.In order to improve this performance,this dissertation proposes a new type of composite component which is composed of polyurethane foam and 6082-T6 circular aluminum alloy tube.This paper conducts a series of axial compression bearing capacity test,finite element simulation and theoretical investigation to obtain the axial compression stability performance of this composite component.The main research work are summarized as follows:Firstly,the tensile test was performed on 15 6082-T6 aluminum alloy specimens(5specifications,3 of each),and the mechanical parameters of aluminum alloy materials with different cross-sections were obtained.Through the compression test of 6 polyurethane foam specimens(2 densities,3 of each),the main mechanical parameters of polyure-thane foams of different densities are obtained.The performance test of stable bearing capacity under axial force was carried out on 17 6082-T6 aluminum alloy round tube specimens,including 5 empty tube specimens and 12 polyurethane foam filled tubes.The whole process response characteristics of the specimen were obtained,including the load-displacement curve at the mid-span position,the load-vertical strain curve,the buckling load and the failure mode of the specimen.The test results show that all 17 specimens have overall bending instability failure.The filling of polyurethane foam does not improve the stability of the 6082-T6 aluminum alloy tube specimen,but it can improve the deformation performance and ductility of the aluminum alloy specimen.The greater the density of the polyurethane foam,the stronger the ability to improve the deformation of aluminum alloy pipe fittings.This paper compares the finite element analysis software ANSYS/LS-DYNA with ABAQUS,In view of the comparison between the simulated load-displacement curve and the literature,the ABAQUS implicit static analysis module,whose modle is simpler while simulation results fit better with the test results,is selected as the finite element analysis platform.Based on 339 finite element simulation calculations,the influence of polyurethane foam density,aluminum alloy type,slenderness ratio,diameter-tothickness ratio,initial defect,cross-section size and shape on the stability of polyurethane foam filled tube under compression is analyzed.The finite element result shows that the polyurethane foam filled in aluminum alloy tube can increase the buckling load of the pipe fittings,and this improvement effect is affected by many factors.Meanwhile,the polyurethane foam can enhance the bending resistance of the pipe fittings.The composite tube can undergo a greater amount of deformation without breaking than the empty tube.Based on the results of experiments and finite element numerical simulations,a calculation method for the axial compressive stability of the polyurethane foam filled aluminum alloy pipe fittings is established.