圆钢管KK′X型节点性能的试验与数值分析

Experimental and Numerical Analysis of the Performance of Circular Hollow Section KK′X Joints

摘要:

采用试验和数值分析方法，对圆钢管桁架空间KK′X型间隙节点的性能开展了研究。首先，对2个不同几何参数的KK′X节点进行了破坏试验，研究了节点变形特征、破坏模式、荷载—变形曲线、极限承载力和应变强度分布等性能。其次，建立了KK′X型节点的有限元模型，其可靠性通过试验得到验证。应用该模型进一步分析了节点塑性区域及其发展过程。研究表明：节点的破坏模式均为主管塑性破坏，受压K支管处主管管壁向内凹进变形最为显著；支管直径增大能显著提高节点的极限承载力；节点相贯线附近应力分布较为复杂，最大的应变强度发生在受压K支管处的主管鞍点，率先进入屈服，之后塑性区域逐渐向外扩展，最终节点域大部分区域进入塑性。

Abstract:

The behavior of multiplanar KK′X gap joints in circular hollow section （CHS） trusses was investigated experimentally and numerically. First， failure tests on two KK′X joints with different geometric parameters were conducted with different geometric parameters to examine their deformation feature， failure mode， load-deformation responses， ultimate bearing capacities， and strain intensity distributions. Next， a finite element （FE） model of KK′X joints was established and validated against the experimental results. The plastic zone and its development were analyzed using this model. The results indicate that the failure mode of the all joints belongs to chord plasticization. The depression deformation of chord wall at K compressive brace came to maximum. Increasing the brace diameter could enhance the ultimate bearing capacity of the joint. The stress distribution near the intersection between brace and chord is more complicated， with the maximum strain intensity occurring at the chord saddle adjacent to the K compressive brace， where yielding initiates first. The plastic zone then propagates outward， eventually encompassing the most region of the joint region.