KT型相贯节点承载力有限元及设计方法分析

对KT型圆钢管空间相贯节点的极限承载力进行非线性有限元分析，揭示KT型相贯节点的受力性能。结果表明：在支杆轴力大小不同的情况下，随着支杆与弦杆直径比角、腹杆与弦杆直径比屉、支杆与弦杆厚度比τ1、腹杆与弦杆厚度比τ2和弦杆径厚比γ的变化，节点发生弦杆局部屈曲模式、腹杆轴向屈曲破坏和支杆强度破坏3种破坏模式；有焊缝的加强作用，节点承载力有所提高；分析支杆与腹杆轴力不同比值情况下的节点承载力，提出KT型节点承载力简化设计公式。

FINITE ELEMENT AND DESIGN METHOD ANALYSIS OF ULTIMATE STRENGTH OF TUBULAR KT-JOINTS

Nonlinear finite-element analysis of multiplanar circular tubular KT-joints was carried out, the behavior of the tubular KT-joints was described. The result showed that there are three failure modes of the joints with the variance of different joint parameters β1(diameter ratio of branch to chord),β2(diameter ratio of another branch to chord),τ1(thickness ratio of branch to chord),τ2(thickness ratio of another branch to chord) and γ(ratio of chord diameter to its thickness) in different situations when the branch under large load and small load. These failure modes are branch strength failure, branch failure and chord local buckling failure. Ultimate strength of KT-joints considering the welding will be enhanced. The ultimate strength of KT-joints with different force ratio of the brances is analyzed, and the simplified design formulae of ultimate strength of KT-joints are put forward.