哑铃形钢管混凝土柱压弯扭复合作用下力学性能试验研究和有限元分析

Experimental study and finite element analysis on mechanical properties of dumbbell⁃shaped concrete⁃filled steel tubular columns under combined compression⁃bending⁃torsion loading

以轴压比(n)、弯扭比(γ)为变化参数,开展了四根圆形和四根哑铃形钢管混凝土构件压弯扭复合作用下的试验,对不同轴压比和弯扭比参数下各构件的扭矩-转角曲线、扭矩-剪应变曲线、破坏模态的变化规律进行分析。结果表明:在轴压比一定的情况下,弯扭比较大时,构件以受弯为主,破坏模式接近“弯型破坏”;弯扭比较小时,构件以绕构件中心扭转为主,破坏模式接近“扭型破坏”。抗扭承载力随着轴压比增加而提高;在γ=2.80时,当n=0.00增大至n=0.11时,圆形和哑铃形钢管混凝土构件抗扭承载力分别提高23%和53%,增大到n=0.22时,圆形和哑铃形钢管混凝土构件抗扭承载力分别提高了23%和99%;抗扭承载力随着弯扭比增加而降低,其中γ=0.90增大至γ=2.80时,圆形和哑铃形钢管混凝土构件抗扭承载力分别下降了46%和51%。通过有限元软件ABAQUS,对压弯扭构件的扭矩-转角全过程关系曲线及破坏模态进行分析,有限元计算结果与试验结果吻合良好。

With the axial pressure ratio(n)and the bending-torsion ratio(γ)as varied parameters,the tests of 4 circular-shaped and 4 dumbbell-shaped concrete-filled steel tubular members under combined compression-bending-torsion loading were carried out,the change rules of the torque-torsion angle curve,torque-shear strain curve and failure mode of each members with the parameters of the different axial pressure ratio and bending-torsion ratio were analyzed.The results show that in the case of the constant value of the axial pressure ratio,when the bending-torsion ratio is large,the member is mainly subjected to bending,and the failure mode is close to flexural feature.When the bending-torsion ratio is small,the member is mainly twisted around the center of the member,and the failure mode is approaching torsional feature.The ultimate torque increases with the increase of the axial pressure ratio.In the case ofγ=280,when the axial pressure ratio increases from 000 to 011,the ultimate torque of the circular-shaped and dumbbell-shaped concrete-filled steel tubular members increases by 23%and 53%respectively,and when the axial pressure ratio increases to 022,the ultimate torque of circular-shaped and dumbbell-shaped concrete-filled steel tubular members increases by 23%and 99%respectively.The ultimate torque decreases with the increase of the bending-torsional ratio,and when the bending-torsion ratio increases from 090 to 280,the ultimate torque of circular-shaped and dumbbell-shaped concrete-filled steel tubular members decreases by 46%and 51%respectively.Through the finite element software ABAQUS,the relation curve of the torque-torsion angle curve and failure mode of the members during the whole process were analyzed.The calculation results by finite element are in good agreement with the experimental results.