钻石鸟嘴式方管T形节点热点应力集中系数分析

Hot Spot Stress Concentration Factors of Diamond Bird-Beak SHS T-Joints

钻石鸟嘴式节点是桁架式方管结构中一种新的焊接节点型式,本文基于疲劳性能研究的需要,应用有限元方法,分别分析了在支管受轴力和平面弯矩作用下这种T形节点的热点应力集中系数SCF,考察了节点无量纲几何参数β,2γ,τ对SCF的影响效应,并将这种新型节点的SCF与传统方管节点的SCF进行了比较。分析表明钻石鸟嘴式节点在支管轴力作用下,支管和主管的热点应力位置都出现在鞍点;在支管平面弯矩作用下,支管和主管的热点应力位置都出现在冠点;钻石鸟嘴式节点的热点应力集中系数显著低于传统方管节点,意味着前者比后者具有更好的疲劳强度。

Diamond bird-beak joint is a new type of welded joint in truss structures made of square hollow section （SHS） members. In need of fatigue behaviour, the hot spot stress concentration factors （SCF） of the type of T -joint under axial force and in -plane bending on the brace respectively were analyzed using finite element method, and the effects of nondimensional geometric parameters β,2γ, and τ on the SCFs were investigated. The feature of SCFs of the bird-beak SHS joints was compared with that of the normal SHS joints. It is concluded that for the bird-beak SHS joints the hot spot stresses both in the brace and in the chord are located at the saddle for the brace subjected to axial force, whereas they are located at the crown for the brace subjected to in-plane bending. The bird-beak SHS joints have much lower SCFs than the normal SHS joints, which indicates that the former joints have better fatigue behaviour than the latter joints.