Study On Fatigue Performance Of T-shaped Stainless Steel Circular Tubular Joints

Stainless steel material is a high-performance green building material with excellent mechanical properties and ornamental properties,which can perfectly combine architectural aesthetics and structural performance,and has a broad application space in building structures.Due to its beautiful appearance,simple joint structure and good mechanical performance,the steel pipe structure is widely used in building structures,marine development,machinery and other industries.At present,the research results on the mechanical properties of the tubular joints of stainless steel pipes at home and abroad are becoming more and more abundant,but the related research on the fatigue properties of the tubular joints of stainless steel pipes is still very scarce,which is also a lack of technology in the promotion and application of stainless steel structures to a certain extent.Based on the above background,this subject takes the stainless steel welded tubular T-joints as the research object,and uses the methods of experiment,finite element analysis,parameter analysis,etc.to study the specimen:(1)The stainless steel raw material in the test was subjected to tensile test,and the mechanical properties of the stainless steel material were obtained,which provided reliable material parameters for the subsequent finite element analysis.(2)The stress concentration factor experiment was carried out on the four stainless steel welded tubular T-joints,and the gradient strain distribution law around the weld of the tubular joint and the maximum hot spot stress position were obtained.On this basis,the stress concentration factors of saddle point and crown point are obtained by mathematical extrapolation.(3)Through the fatigue performance experiment of four stainless steel welded tubular T-joints,the crack initiation position,crack propagation law,fatigue life and stiffness degradation characteristics of the tubular joint under axial constant amplitude fatigue load are obtained,and the fatigue failure law is revealed.(4)Through the finite element software ANSYS and fatigue analysis software n Code Design Life,the finite element simulation calculation of the stainless steel welded tubular T-joints is carried out as the verification and supplement of stress concentration factor test and fatigue test.(5)The influence of different dimensionless parameters on the stress concentration factor is obtained by expanding the demonstrated finite element model.Based on the parameter analysis,the SCF parameter formula of T-shaped stainless steel circular tubular joints with good accuracy is obtained.