钢管混凝土圆形支架压弯力学性能

Analysis on bending performance of round support stent with concrete filled steel tube in ABAQUS

通过试验对均布加载条件下矢跨比为0.26的钢管混凝土圆形支架拱顶弧段和左右帮段变形进行了监测,并结合ABAQUS对钢管混凝土抗弯过程进行全过程仿真三维数值模拟分析。同时通过内嵌一种无厚度黏聚力粘结单元的混凝土损伤模型,从微观方面更为准确地展示了钢管混凝土短柱,以及核心混凝土试件受压破坏过程中产生的裂纹扩展和剥落程度。结果表明:随着支架顶弧段和两帮段均压让压层厚度的增加,钢管混凝土圆形支架的承载能力逐渐增大,进而减弱了支架四段圆弧拱整体的轴力,降低了钢管与内部核心混凝土的变形、破坏速度。同时核心混凝土试件在受压过程中产生裂缝,继续施加荷载,由于裂缝的存在导致核心混凝土体积膨胀,从而使钢管混凝土短柱压缩鼓包。研究成果可为了解钢管混凝土力学性能和支架模拟让压空间的工况提供参考。

Through the monitoring on the deformation of the middle section and the left-right side section in the concrete filled steel tube（CFST）support with the condition of uniform loading,as well as the strain and the ultimate bearing capacity of outer steel pipe and inner core of concrete,and combining with ABAQUS,a simulation analysis was conducted on the bending process with cohesive elements as the main research method in the constitutive model of concrete.This finite analysis method used the three-dimensional numerical simulation which displayed accurately on the whole progress of uniaxial compression experiment with CFST short column and core concrete test block in the micro aspects.The actual morniting analysis shows that the bearing capacity of the support increases with the gathering of the thickness of the middle section and left-right side section in the range of a certain thickness for the letting pressure layer,which weaken the axial force of the support in the CFST arch and decreased with the deformation and destruction tempo of core concrete in the CFST support.There were some cracks appeared in the process of pressing,when the loading increased,the presence of cracks leaded to a concrete volume expansion,and then made the CFST short column drum package.After reaching the ultimate load the yield of CFST circular arch was one of the hoop action failure of the concrete.Not only the boundary condition of different layer of the CFST support can lead a better understandingon the mechanical properties of CFST,also there is a certain engineering guidance significance to the non-dense pressure construction condition.