DISTRIBUTION OF RESIDUAL STRESS IN THE SPHERE-PIPE CONNECTION WELDS OF WELDED HOLLOW SPHERICAL JOINTS

Abstract

Welded hollow spherical joint is widely used in large-span spatial structures due to its simple structure, clear mechanical behavior and convenient connection. However, a large number of sphere-pipe connection welds at the joints will inevitably produce complex welding residual stress, which will have adverse effects on the stiffness of the joints and the overall safety of the structure. Focusing on the sphere-pipe connection welds on the hollow spherical joints, this paper keeps track of the whole process of sphere-pipe welding, analyzes and summarizes the distribution law and specific distribution mode of welding residual stress on the joints and parametrically analyzes the influence trend of the configuration dimension of joints on the distribution of welding residual stress. Studies have found that the circumferential welding residual tensile stress is mainly concentrated in and near the weld, while the compressive stress is concentrated in the outer area of the weld. The longitudinal residual stress shows the obvious bending features of external compression and internal tension along the wall thickness direction near the weld; The configuration dimension of the hollow spherical joint mainly affects the influence range of welding residual stress, that is, with the change of dimension, the welding heat-affected zone on steel pipes will vary within the area with a distance to the weld 0.6~1.35 times the diameter, and the heat-affected zone on spherical joints will vary within the area with a distance to the weld no more than 0.5 times the diameter. The above-mentioned refined research on the residual stress of the hollow spherical joint can lay a foundation for the accurate evaluation of the stiffness and overall safety of the welded hollow spherical joints.