Experimental study on mechanical properties of conical head for bolted spherical joints

As a typical grid structure joint, bolted spherical joints are widely used in various engineering. However, as the key component of the bolted spherical joint, the conical head has not formed a unified specification and standard in China. At the same time, the mechanical properties and failure mode of the conical head are not clear. Therefore, this paper has carried out axial tension tests on 18 specimens with 6 kinds of conical heads. Combined with finite element analysis, the mechanical properties, failure mode, bearing capacity, and the factors affecting the bearing capacity of the conical head under axial tension were studied. The calculation formula of the bearing capacity of the conical head was proposed. The results show that the conical head is in a complex stress state of bending, shear and compression at the same time, and the failure mode of the conical head is the shear failure of the bottom plate. The thickness of the bottom plate of the conical head and the bolt specification will affect the bearing capacity of the conical head. The conical head's bearing capacity decreases with decreasing bottom plate thickness and bolt specification. However, the thickness of the bottom plate and the bolt specification will not affect the failure mode of the conical head.