Study On Mechanical Properties Of Concrete-Filled Aluminum Tubular Medium Long Columns Under Compression

Compared with steel used in the common structure,aluminum alloy has the outstanding advantages of light weight,high strength,corrosion resistance and high recycling rate.It is an environment-friendly building material that can replace steel in some cases.Therefore,more and more attention has been paid to the mechanical properties of various types of aluminum alloy pipe filled with concrete and its components.However,due to the obvious differences between the physical and mechanical properties of aluminum alloy and steel,the existing design theory of concrete-filled steel tubular structure can not be completely applied to the calculation of concrete-filled aluminum tubular structure.Therefore,the research on the mechanical properties of concrete-filled aluminum tubular structure has very important theoretical value and practical engineering significance.The main research results are as follows.Considering the influence factors of cross-section form and aluminum content,the mechanical properties of 9 circular concrete-filled aluminum tubular stub columns and 3 square concrete-filled aluminum tubular stub columns under axial compression were studied.The ultimate bearing capacity,failure mode,load-axial displacement curve and load-longitudinal and transverse strain curve were obtained,and the influence rules of various factors on the mechanical properties of the stub columns under axial compression are revealed.Considering the influence factors such as section form,aluminum content,slenderness ratio and eccentricity,the mechanical properties of 12 circular concrete-filled aluminum tubular medium long columns and 6 square concrete-filled aluminum tubular medium long columns under eccentric compression are studied.The ultimate bearing capacity,failure mode,load axial displacement relation curve,load mid span deflection relation curve,lateral deflection deformation curve and load longitudinal and transverse strain relation curve of each specimen are obtained,and the influence rules of various factors on the mechanical properties of the medium long columns under eccentric compression are revealed.Based on the finite element software ABAQUS,the finite element analysis models of all concrete-filled aluminum tubular stub columns and medium long columns are established,and the reliability of the finite element modeling method and the corresponding models is verified by comparison.On this basis,the parameter expansion analysis is carried out for the slenderness ratio,eccentricity,aluminum content and core concrete strength of concrete-filled aluminum tubular columns,and the influence rules of various parameters on the mechanical properties of concrete-filled aluminum tubular medium long columns are further revealed.Combined with the existing research conclusions and the test results of this paper,the applicability and accuracy of the existing calculation models and methods of concrete-filled steel tubular columns at home and abroad for predicting the bearing capacity of concrete-filled aluminum tubular columns are compared and analyzed.Based on the conclusion of finite element simulation,the slenderness ratio reduction coefficient and eccentricity reduction coefficient of concrete-filled aluminum tubular medium long columns are obtained by fitting,and the simplified calculation method of stability bearing capacity of concrete-filled aluminum tubular medium long columns under eccentric compression is proposed.Through the comparison,it is found that the calculation results of the formula are in good agreement with the test results and the finite element simulation results,and are safe,which can provide the calculation basis for the relevant engineering design and evaluation.This paper has 99 pictures,28 tables and 99 references.