| Aluminum alloy materials are widely used in various fields due to their excellent properties.At present,most aluminum alloys used in building structures are 6xxx series and 5xxx series aluminum alloys.The tensile strength of these aluminum alloys is not more than 350 Mpa,which is difficult to meet the strength requirements of high-rise buildings,long-span structures and special structures at this stage.The tensile strength of 7A04 high strength aluminum alloy can reach 600 MPA,which is a kind of material to meet the needs of modern engineering structures.At present,there are relatively few studies on 7A04 aluminum alloy members at home and abroad,and the mechanical properties of 7A04 aluminum alloy members cannot be mastered.Axial compression members are the most basic structural components.In this paper,the axial compression stability of 7A04 aluminum alloy circular tubes is studied by means of experimental study,finite element simulation and theoretical analysis.The main research contents are as follows:In this paper,the axial compression test of 18 7A04 aluminum alloy circular tubes was completed.The test specimens include two kinds of diameter-thickness ratio and seven kinds of slenderness ratio.The data of the failure mode,ultimate bearing capacity,load-displacement curve and load-strain curve of each specimen were obtained by the test.Secondly,the corresponding finite element model was established according to the test model,and the accuracy of the finite element model was verified by the test results.Based on the verified finite element model,the effects of initial geometric imperfections,strain hardening index n in Ramberg-Osgood constitutive model and section sizes on the stability coefficient of axial compression were analyzed.Finally,the axial compression stability of 160 7A04 aluminum alloy circular tubes was parametrically analyzed.The parametric analysis members include 8 kinds of section sizes,and the slenderness ratio ranged from 5 to 150.Finally,the calculation methods of axial compression stability coefficient in each code were compared and analyzed.According to the test values and the finite element parametric analysis value in this paper,the proposed calculation formula for calculating the stability coefficient based on the Code for Design of Aluminum Alloy structures in China was put forward,and the calculation results of the proposed formulas were compared with those of the existing calculation methods.The results show that the axial compression stability bearing capacity of 7A04 aluminum alloy circular tubes predicted by the proposed calculation formula is the closest to the test value and finite element analysis value. |
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