圆中空夹层钢管混凝土压扭构件有限元分析

Theoretical research on concrete filled double-skin steel tubular members subjected to compression and torsion

利用软件ABAQUS对圆中空夹层钢管混凝土压扭构件进行有限元分析,对构件的破坏形态、剪应力在横截面上的分布、内外钢管与混凝土的相互作用、内外钢管与混凝土各自承担的荷载进行了分析,研究了先扭后压和先压后扭两种加载工况对圆中空夹层钢管混凝土压扭构件工作机理的影响。并对先压后扭加载工况下空心率对钢管、夹层混凝土各自承担荷载的影响规律进行分析。结果表明:不同加载工况对圆中空夹层钢管混凝土压扭构件工作机理的影响不大;加载方式不同,钢管与混凝土相互作用的发展过程不同,极限荷载时先压后扭加载工况下的外钢管与混凝土相互作用力略大;在压扭复合作用下,构件破坏时,混凝土承担较大的轴力,钢管承担较大的扭矩;空心率越大,构件中混凝土承担的扭矩越小。

The behaviors of concrete filled double skin-steel tubular(CFDST) members under axial compression and torsion were studied using the finite element software ABAQUS.The influence of two kinds of loading cases on the working mechanism of the CFDST members was discussed from four aspects,including failure modes,shear stress distributions on the cross section,interactions between steel tubes and concrete and loads undertaken respectively by steel tubes and concrete.And the influence of different hollow ratios on the loads resisted by steel tubes and concrete was analyzed under the first loading case that axial load was applied firstly and kept constant,then torque was applied on the component.The results indicate that different loading cases have little effect on the working mechanism of the CFDST members;the development process of the interactions between steel tubes and concrete is different under two kinds of loading cases;when the load reaches the ultimate load the confining stress between outer steel tube and concrete is larger under the first loading case;when the components are damaged,concrete resists a large portion of axial force while steel tubes resist most of torque;with the increase of hollow ratio,the torque resisted by concrete is reduced.