薄壁钢约束方木柱轴心抗压性能有限元模拟

Numerical simulation of the axial compression preformance of prestressed thin-walled steel confined square timber column

为探究合理有效薄壁钢约束方木柱轴心受压有限元分析模型,以及预应力对该薄壁钢约束方木柱轴心受压性能的影响;采用ABAQUS有限元软件建立了薄壁钢约束方木柱模型,采用"静摩擦-动摩擦指数衰减"接触模拟了薄壁钢与方木柱的相互作用,采用自定义场输出转换器单元实施了预应力的施加。基于合理有效有限元分析模型,进行预应力度k(钢材表面拉应力σ_(con)与钢材屈服强度f_(y)比值)=0、0.1、0.15、0.2和0.25对薄壁钢约束方木柱轴心抗压性能影响分析。分析结果表明,数值模拟结果与试验结果吻合良好,k=0相较于k≠0的试件屈服荷载、极限荷载和残余强度都更低,且更早进入塑性阶段,残余强度随着k的增加而下降;但k并非越大越好,过大的k会造成钢材部分区域屈服,削弱主动围压的效果;由于预应力的存在,预应力薄壁钢约束方木柱具有更好的承载力性能和延性。

In order to present a rational and effective numerical simulation model for the axial compression preformance of the prestressed thin-walled steel confined square timber column,and to clarify the influence of magnitude of prestress on the the axial compression preformance of the prestressed thin-walled steel confined square timber column,a numerical simulation model is established through ABAQUS,the static friction dynamic friction index attenuation contact is used to simulate the interaction between prestressed thin-walled steel and square timber column,and the prestress force is applied by using the field output converter unit.Based on the rational and effective numerical simulation model,the influence analysis is conducted for the magnitude of prestress k=0,0.1,0.15,0.2 and 0.25 on the the axial compression preformance of the prestressed thin-walled steel confined square timber column.The results show that the numerical simulation results are in good agreement with the test results.The yield load,ultimate load and residual strength of the prestressed thin-walled steel confined square timber column with k=0 are lower than those with k≠0,the prestressed thin-walled steel confined square timber column with k=0 enter the plastic stage earlier,the residual strength decreases with the increase of the magnitude of prestress,however,the larger the value k is,the effect of the active confining pressure will be weakened.Due to the existence of prestress,the prestressed thin-walled steel confined square timber column has better bearing capacity and ductility.