圆钢管焊接空心球节点受压破坏机理与试验研究

Destructive mechanism and experimental study of welded hollow spherical joints connected with circular steel tubes

从球体钢材屈服强度的角度对受压破坏机理进行研究。采用弹塑性线性强化材料本构模型建立有限模型,考虑几何非线性,利用弧长法对受压球节点进行了全过程受力分析。系统研究了受压球节点的承载能力和破坏机理,节点因材料屈服形成塑性环铰而无法继续承载,材料屈服强度是影响承载力的主要因素。提出了破坏控制截面的概念,剪应力是破坏截面的控制应力。采用Q235B和Q345B材质的4组8个典型球节点试件的对比性破坏试验研究,直观了解节点的受力性能和破坏机理,验证了有限元分析的正确性。最后,利用冲切模型对受压承载力进行了理论分析,建立了承载力实用计算公式,可以直接应用于工程设计。

The failure mechanism and carrying capacity of hollow spherical joints were investigated in this paper. Based on the linear hardening elasto-plastic model and geometric nonlinearity, the whole loading course of joints under axial load was calculated by the use of arc-length method. It was found that the yield strength of hollow sphere directly affected carrying capacity, and the loop-plastic hinge resulted in the failure of joint. Further analysis demonstrated that the shearing stress was the dominant factor in the failure section. In order to investigate the collapse mechanism of the joint, test on 8 typical full-scale joints made of Q235B and Q345B were carried out and the finite element analysis was validated. Finally, the theoretical carrying capacity was obtained based on the punching shear failure model , and the practical calculation method was established for the joints subject to axial compressive forces, which can be applied in practical design.