Analysis For The Welded Empty Sphere Joint With Incompletely Filled Groove Defect

Presently, the welded empty sphere and steel tube joint is applied widely. The circle welding seam fractures of steel tube and empty sphere is welded in full orientation difficultly and the welding circumstance is bad. So there are kinds of welding defects unavoidable. Among these defects, incompletely filled groove defect is one of the most dangerous defects. Therefore, it is an important subject to accurately estimate the effect of incompletely filled groove on welded empty sphere joint's stress distribution, ensuring the joint's safety.Based on summarizing the results of the former researchers and dissecting the theory of FEM (finite element method), the FEM software ANSYS 6.1 is conducted on the welded empty sphere and steel tube joint in this paper .The stress of whole calculating model is studied; stress concentration coefficient under incompletely filled groove defect around the joint of empty sphere and steel tube is calculated; effects of the incompletely filled groove depth and the leg length of reinforced circle welding seam on sphere joint's stress concentration is studied ; Discussion is done on the feasibility of reinforcing the super-scaled incompletely filled groove sphere joint with fillet weld, the methods for safety assessment for welded structure which based on the development of fracture mechanics are applied to assessing the safety of welded empty sphere joint with incompletely filled groove defect and ensuring the safety of welded empty sphere joint reinforced with fillet weld.The stress distribution on welded empty sphere joint with incompletely filled groove defect is calculated in this paper through the FEM, which overcome the shortages of the test methods, and can testify the measuring results of the test methods as well. So it is important to science research or engineering application.