循环轴向加载钢管塑性铰性能的试验研究

Experimental Study on Plastic Hinge Performance of Cyclical Axially Loaded Plastic Hinges

针对强震作用下螺栓球网格结构杆件塑性铰超低周疲劳断裂问题,设计了两端带螺栓球节点的圆钢管组合试件模型。对三种高强螺栓的管球组合试件进行了大位移循环加载试验,开展了螺栓球网格结构杆件塑性铰位置、范围、形状及形成机理的研究。试验结果表明:两端带螺栓球节点的圆钢管杆件中部首先进行塑性变形;在往复荷载作用下,塑性变形区域不断沿杆件轴向扩展,杆件塑性铰在拉荷载下缩颈,在压荷载下截面椭圆化,中部区域刚度退化形成凹陷,最终开裂;塑性铰产生的位置在距杆件中点截面直径大小的高度范围内。

Round steel pipe specimen models with two bolt joint balls at both ends have been designed for the purpose of dealing with the problem of rupture of plastic hinge due to the effect of super low cyclical fatigue of blot ball grid structure under the force of strong quakes. Super displacements cyclical charge tests have been carried out for three types of specimens of high-strength bolts, and research is done concerning the position,range,shape and formation mechanism of the plastic hinges for bolt ball grid structure. The results show that, for the round steel pipe specimen with two bolt balls, the middle part firstly starts to have plastic deformation, and then the deformation area extends continuously to the axe under the cyclical charge, the middle part contracts under the tensile strength and the section part ovalizes under pressure, the stiffness of middle part degrades and depression area is formed, at last cracks;the location of plastic hinge lies within the height of the section diameter of the middle part.