A kind of concrete-filled lattice rectangular steel tube(CFLRST)column was put forward.The numerical simulation was modeled to analyze the mechanical characteristic of CFLRST column.By comparing the load-deformation c...A kind of concrete-filled lattice rectangular steel tube(CFLRST)column was put forward.The numerical simulation was modeled to analyze the mechanical characteristic of CFLRST column.By comparing the load-deformation curves from the test results,the rationality and reliability of the finite element model has been confirmed,moreover,the change of the section stiffness and stress in the forcing process and the ultimate bearing capacity of the column were analyzed.Based on the model,the comparison of ultimate bearing capacity and ductility between CFLRST column and reinforced concrete(RC)column were also analyzed.The results of the finite element analysis show that the loading process of CFLRST column consists of elastic stage,yield stage and failure stage.The failure modes are mainly strength failure and failure of elastoplastic instability.CFLRST column has higher bearing capacities in comparison with reinforced concrete columns with the same steel ratio.In addition,the stiffness degeneration of CFLRST column is slower than RC column and CFLRST column has good ductility.展开更多
The dynamic control equation of a new prestressed partially concrete-filled rectangular steel tube(CFRT)beam can be derived based on D’Alembert’s principle.It is used to infer the theoretical results of the dynamic ...The dynamic control equation of a new prestressed partially concrete-filled rectangular steel tube(CFRT)beam can be derived based on D’Alembert’s principle.It is used to infer the theoretical results of the dynamic characteristics for the prestressed CFRT beam.Additionally,the finite element model is set up by ABAQUS for simulation analysis.The results show that the natural vibration frequencies and mode function of the prestressed CFRT simply supported beam calculated by the theoretical formulas are reliable since the relative errors of the first-order frequencies under different prestressing levels are within 6%compared with the finite element results.Further analysis of the prestressing parameters is carried out using the theoretical formulas,in which factors such as the prestressing level,eccentricity of tendons,and tensile stiffness of prestressed tendons have different influences on the natural vibration frequencies.Finally,it provides a theoretical basis for the dynamic design of the prestressed CFRT beams.展开更多
For QSTE700 high-strength steel rectangular welded tube,the mechanical properties of the weld zone vary with the distancefrom the centerline of the weld.Therefore,the accurate description of constitutive relationship ...For QSTE700 high-strength steel rectangular welded tube,the mechanical properties of the weld zone vary with the distancefrom the centerline of the weld.Therefore,the accurate description of constitutive relationship of the weld zone is of greatsignificance for the study of formability of QSTE700 rectangular welded tube.Firstly,the mechanical properties of parentand mixed specimens containing weld zone and parent zone were obtained by uniaxial tensile test.And based on the micro-hardness test,the width and the microhardness distribution of the weld zone were determined.Secondly,by subdividingthe weld zone into several small areas,and combining with the rule of mixtures and nanoindentation test,the continuous functional relationships of strength coefficient K,hardening coeffecient n and elastic modulus E were obtained,and then,the continuous constitutive relationship of QSTE700 rectangular welded tube was established.Finally,the validity and reliability of the continuous constitutive relationship of welded tube were verified by nanoindentation fest and rotary drawbending of rectangular welded tubc.Besides,it was found that the finite element model of rotary draw bending of QSTE700 rectangular welded tube established by using the continuous constitutive relationship can well simulate the cross sectiondeformation and wall thickness variation.展开更多
基金This work was financially supported by the Fundamental Research Funds for the Central Universities(JUSRP11819),National Natural Science Foundation of China through Grant 51378240,2015 Jiangsu provincial building energy saving and construction industry science and technology project,2016 Jiangsu provincial construction industry modernization base project.
文摘A kind of concrete-filled lattice rectangular steel tube(CFLRST)column was put forward.The numerical simulation was modeled to analyze the mechanical characteristic of CFLRST column.By comparing the load-deformation curves from the test results,the rationality and reliability of the finite element model has been confirmed,moreover,the change of the section stiffness and stress in the forcing process and the ultimate bearing capacity of the column were analyzed.Based on the model,the comparison of ultimate bearing capacity and ductility between CFLRST column and reinforced concrete(RC)column were also analyzed.The results of the finite element analysis show that the loading process of CFLRST column consists of elastic stage,yield stage and failure stage.The failure modes are mainly strength failure and failure of elastoplastic instability.CFLRST column has higher bearing capacities in comparison with reinforced concrete columns with the same steel ratio.In addition,the stiffness degeneration of CFLRST column is slower than RC column and CFLRST column has good ductility.
基金the National Natural Science Foundation of China(No.51878407)。
文摘The dynamic control equation of a new prestressed partially concrete-filled rectangular steel tube(CFRT)beam can be derived based on D’Alembert’s principle.It is used to infer the theoretical results of the dynamic characteristics for the prestressed CFRT beam.Additionally,the finite element model is set up by ABAQUS for simulation analysis.The results show that the natural vibration frequencies and mode function of the prestressed CFRT simply supported beam calculated by the theoretical formulas are reliable since the relative errors of the first-order frequencies under different prestressing levels are within 6%compared with the finite element results.Further analysis of the prestressing parameters is carried out using the theoretical formulas,in which factors such as the prestressing level,eccentricity of tendons,and tensile stiffness of prestressed tendons have different influences on the natural vibration frequencies.Finally,it provides a theoretical basis for the dynamic design of the prestressed CFRT beams.
基金The authors would like to thank the Science and Technology Plan Project of Shenzhen Science and Technology Innovation Committee(JCYJ20180306171058717)Natural Science Basis Research Plan in Shaanxi Province of China(2019JZ-03).
文摘For QSTE700 high-strength steel rectangular welded tube,the mechanical properties of the weld zone vary with the distancefrom the centerline of the weld.Therefore,the accurate description of constitutive relationship of the weld zone is of greatsignificance for the study of formability of QSTE700 rectangular welded tube.Firstly,the mechanical properties of parentand mixed specimens containing weld zone and parent zone were obtained by uniaxial tensile test.And based on the micro-hardness test,the width and the microhardness distribution of the weld zone were determined.Secondly,by subdividingthe weld zone into several small areas,and combining with the rule of mixtures and nanoindentation test,the continuous functional relationships of strength coefficient K,hardening coeffecient n and elastic modulus E were obtained,and then,the continuous constitutive relationship of QSTE700 rectangular welded tube was established.Finally,the validity and reliability of the continuous constitutive relationship of welded tube were verified by nanoindentation fest and rotary drawbending of rectangular welded tubc.Besides,it was found that the finite element model of rotary draw bending of QSTE700 rectangular welded tube established by using the continuous constitutive relationship can well simulate the cross sectiondeformation and wall thickness variation.
