圆FRP-混凝土-碳素钢管轴压短柱试验研究及有限元模拟

Experimental study and finite element simulation of circular FRP-concrete-carbon steel tubular short columns under axial compressive load

对9根圆FRP-混凝土-碳素钢管短柱开展了轴压试验,构件仅改变外包FRP层数。经过试验,获得了构件的整体破坏模态和载荷-位移曲线。通过ABAQUS对构件展开模拟,首先仅改变构件外包FRP的层数,模拟的结果与轴压结果吻合得较好。分析结果表明,所有构件均表现出脆性破坏性质,在试验范围内随着构件FRP层数的增加,其极限载荷大幅增大;载荷-位移曲线均具有弹性段、弹塑性段和下降段。端板对构件极限载荷的作用不大,但对构件的最后破坏部位有极大影响。接着又通过建模分别分析了空心率、混凝土的强度级别和内管径厚比对构件极限载荷的作用。只改变构件的单一因素,通过分析可知:当空心率增长时,构件极限载荷逐渐减小;当混凝土的强度级别增长时,构件极限载荷呈较小增长趋势;当内管径厚比增加时,构件极限载荷缓慢降低。通过对比可得FRP层数对构件极限荷载的影响最大,内管径厚比的影响最小。

Nine circular FRP-concrete-carbon steel tubular short columns were carried out under axial compression.Specimens only changed FRP layers.Through the axial compression test, the whole failure pattern and the vertical load-displacement curve of specimens were obtained.Specimens were simulated through the finite element software ABAQUS, firstly FRP layers was the only factor which was changed.Compared with experimental datum,the results of the simulation were well validated.The results of the analysis show that all specimens show the nature of the brittle Pailure.Within the scope of the experiment, with the increase of FRP layers the ultimate bearing capacity increases sharply.The load-displacement curves all have elastic stage,elastic-plastic stage and decline stage.End plates have little effect on the ultimate load of specimens ,but have great effect on finally destroyed parts of specimens.Then hollow section ratio, concrete strength level and tube diameter-to-thickness ratio were raised to study the impact on the ultimate load of specimens by building models. Through changing the single factor of specimens, from the analyses we could know that the ultimate load of specimens decreases gradually with the increase of hollow section ratio, the ultimate load of specimens increases at a slow trend along with the growth of the strength of concrete, the ultimate load of specimens decreases slowly with tube diameter-to-thickness ratio increasing.Compared with other factors, we can know that FRP layers has the largest influence on the ultimate load of specimens, the influence of tube diameter-to-thickness ratio is the smallest.