| People have more and more used aluminum alloy material.Compared with steel,aluminum alloy material has the advantages of light weight,strong toughness,extrusion molding,good corrosion resistance,recycling and low maintenance costs.The reason why aluminum alloy is used less than steel is mainly that the unit price of aluminum alloy material is higher,but,according to previous studies,from the perspective of the whole life cycle,the overall cost of aluminum alloy structure is lower than that of steel.Today’s carbon peak and carbon-neutral era is undoubtedly more environmentally friendly and sustainable to use aluminum alloy materials more.At present,the Chinese standard "Aluminum alloy structure Design Code" GB50429-2007 was issued 15 years ago,and part of the coefficient reference data is the test data before 2007,still,it did not consider the current application and research more materials such as 6082-T6 and 7A04-T6.This paper aims to use the fiber model which is more efficient than ABAQUS and other finite element software to put forward the corresponding calculation method to analyze the overall stability of aluminum alloy axial compression members and eccentric compression members.The finite element software ABAQUS was used to supplement the fiber model,and the local stability of aluminum alloy axial compression components was further considered.Finally,the reliability analysis of 7A04-T6 materials is carried out.The main work of this paper is as follows:1 In this paper,based on the theory of fiber model numerical method,the software MATLAB is used to write a set of programs for the overall stability analysis of aluminum alloy compression components.To solve the problem of the low computational efficiency of the traditional dichotomy method for calculating the strain at the neutral axis of the cross-section,the quasi-Newton method is used to replace the traditional dichotomy method in the iterative calculation,and the computational efficiency is improved by reducing the iterative steps.2 The application of the fiber model method in the calculation of the stability of aluminum alloy eccentrically loaded members is verified.The effects of slenderness ratio and initial geometric defects on the overall strength of the biased component are discussed.The results of parametric analysis and test data collected were compared with the European code.Based on the European code with higher calculation accuracy,a formula for calculating the stable bearing capacity of the biased member with box section was proposed.3 A systematic analysis of the global stability of H-and box-shaped aluminum alloy axial compression components was carried out.The influence of parameters such as initial bending and strain hardening coefficient on the overall stability of components is discussed by parametric analysis.Finally,the American codes’ coefficients are fitted using the parametric analysis results,and some design suggestions are put forward.4 In view of the problem that the calculation method of the bearing capacity of the fiber model cannot discuss the buckling of the plate,a corresponding finite element model is established in this paper to study the influence of local buckling on the overall stability bearing capacity,which is verified by the existing local stability test.On this basis,parametric analysis was carried out,local flexion subtraction formula was obtained by fitting,and local stability bearing capacity calculation formula was put forward.By comparing with experiments and existing methods,it is proved that the proposed method can better predict local stability bearing capacity.5 The latest test database of aluminum alloy axial compression components has been established as of July 2021.Reliability analysis of aluminum alloy axial compression components of 7A04-T6 was carried out.On the basis of this,the partial coefficient of resistance of three types of materials under axial compression is discussed,and some suggestions for Chinese standard are put forward.The result of research shows:1 The stability bearing capacity calculation program based on fiber model can well predict the overall stability bearing capacity of aluminum alloy compression members.The established finite element model can better predict the local stability bearing capacity.2 In this paper,the formula for calculating the overall stability bearing capacity of compressive members and the formula for calculating the local stability bearing capacity of axial members are improved on the basis of the existing methods,and can calculate the stability bearing capacity more accurately.3 The bearing capacity of aluminum alloy eccentrically compressed members decreases with the increase of slenderness ratio.The overall geometric initial defects have a great influence on the stability of axial compression components,while the strain hardening coefficient has a little influence.4 The increase of width-thickness ratio will produce more local flexion reduction effect.The interaction between adjacent plates decreases with the increase of width-thickness ratio.5 For 7A04-T6 aluminum alloy axial compression components,the coefficient of resistance proposed in the current specification is uneconomical,and it is suggested to adopt the coefficient of resistance of 1.1. |
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