Research On Ultimate Load-bearing Capacity Of Drum-type Steel Tubular Joint

Spatial tubular simple joint locates on main chord, with which several branches are directly connected by weld, so the chord suffers complex stress state. Sometimes joint range may outrun the diameter of chord due to prodigious diameter of branches. A new drum-type steel tubular joint is proposed in this thesis. It resolves such problem effectively.This thesis makes use of non-linear finite element analysis by software ANSYS, analyzes the ultimate tensile bearing capacity of K type drum-type steel tubular joint when angle and thickness of close armor plate, thickness, length and diameter of outer tube change. Results show that reasonable application of drum-type steel tubular joint can enhance the ultimate tensile bearing capacity effectively, be added more branches, and improve the mechanics performance of joint.The advantage of drum-type steel tubular joint could be embodied adequately only if the ring-stiffener is set on the joint, which is placed between inner tube and outer tube and transfers the load from outer tube to inner tube, and offer outer tube out-plane support. Taking the K type drum-type steel tubular joint for example, the ultimate load-bearing capacity and stiffness of ring-stiffened drum-type steel tubular joint are analyzed under different ways, numbers, thickness and size of ring-stiffener, and compared with unstiffened K-type tubular joint. Results show that such joint with right ring-stiffener can improve the ultimate load-bearing capacity and stiffness of tubular joint effectively.Steel tubular overlapped joint is frequently applied in spatial structure. The ultimate load-bearing capacity of K type and KK type drum-type steel tubular joint is analyzed by the non-linear finite element analysis in this thesis. Results show that they have obvious difference of mechanics performance between ordinary simple joint and overlapped joint. It should be considered respectively when design calculation. They have different effect between with and without hidden weld under different load mode. Because the load condition is complex in practice, the hidden parts welded are advised.Taking the X type drum-type steel tubular joint analysis, work out the ultimate tensile bearing capacity of drum-type steel tubular joint which is influenced by thickness, length and diameter of outer tube and thickness, angle of close armorplate. The ultimate tensile bearing capacity of a special drum-type steel tubular joint which outer tube lean to one side of inner tube are calculated too, and compared with corresponding welded hollow spherical joint. Results show that drum-type steel tubular joint can enhance the ultimate tensile bearing capacity and stiffness of tubular joint. To some extent, the ultimate tensile bearing capacity of drum-type steel tubular joint is higher than the corresponding welded hollow spherical joint.