Effect of Welding Residual Stress on the Buckling Behavior of Storage Tanks Subjected to Harmonic Settlement

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Jian-Guo Gong ◽  
Lei Yu ◽  
Feng Wang ◽  
Fu-Zhen Xuan
Keyword(s):  
Residual Stress ◽  
Design Method ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Strengthening Effect ◽  
Storage Tanks ◽  
Buckling Strength ◽  
Welding Joint ◽  
Buckling Behavior ◽  
Significant Difference

The effect of welding residual stress on the buckling behavior of storage tanks subjected to the harmonic settlement was simulated using the shell-to-solid coupling method. In the numerical model of tanks coupled with the welding residual stress, the welding joint and its adjacent zone were modeled using the solid submodel and the zone far away from the welding joint was built by the shell submodel. Effects of welding parameters (e.g., welding velocities and welding passes) on the buckling behavior of tanks were analyzed systematically. Results indicate that the buckling strength of tanks is enhanced due to the welding residual stress. Comparatively, a slow welding velocity presents a more remarkable strengthening effect than the fast welding velocity due to a larger axial residual stress produced at the welding joint. Nevertheless, no significant difference between the double-side welding and the one-side welding for buckling strength enhancement is observed for the cases studied. This indicates that the current design method causes a conservative design without considering the welding residual stress.

scholarly journals Study on Residual Stress of Welded Hoop Structure

2020 ◽  
Vol 10 (8) ◽  
pp. 2838
Author(s):  
Wenbo Ma ◽  
Heng Zhang ◽  
Wei Zhu ◽  
Fu Xu ◽  
Caiqian Yang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Speed ◽  
Weld Seam ◽  
Outer Cylinder ◽  
Three Dimensional ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Forming Process ◽  
Maximum Residual Stress

Residual stress is inevitable during welding, which will greatly affect the reliability of the structure. The purpose of this paper was to study the residual stress of the hoop structure caused by the cooling shrinkage of the weld when the outer cylinder was wrapped and welded under the condition of the existing inner cylinder. In this paper, the “method of killing activating elements” of ANSYS was used to simulate the three-dimensional finite element of the hoop structure. In the case of applying interlayer friction, the welding-forming process and welding circumferential residual stress of the hoop structure were analyzed. The blind hole method was used to test the residual stress distribution of the hoop structure, and the test results were compared with the finite element simulation results to verify the reliability of the simulation calculation method and the reliability of the calculation results. Then, the influence factors of the maximum welding residual stress of the hoop structure were studied. The results show that the maximum residual stress of the outer plate surface of the hoop structure decreases with the increase of the welding energy, the thickness of the laminate, the width of the weld seam, the welding speed, and the radius of the container. Based on the results of numerical simulation, the ternary first-order equations of the maximum residual stress of the hoop structure with respect to the welding speed, the thickness of the laminate, and the width of the weld seam were established. Then, the optimal welding parameters were obtained by optimizing the equations, which provided an important basis for the safe use and optimal design of the welding hoop structure.

Influence of Welding Parameters on Residual Stress in 9% Ni Steel for Low Temperature Service

2010 ◽  
Vol 154-155 ◽  
pp. 1618-1623 ◽  
Author(s):  
Chun Yan Yan ◽  
Wu Shen Li ◽  
Shi Wu Bai
Keyword(s):  
Residual Stress ◽  
Temperature Field ◽  
Welded Joint ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Transformation Theory ◽  
Element Analysis ◽  
Heat Transfer Theory ◽  
Longitudinal Residual Stress ◽  
Simulation Results

Based on welding heat transfer theory, heat elastoplasticity theory and phase transformation theory, welding residual stress in multi-layer welded joint of 9% Ni steel for liquefied natural gas (LNG) storage tanks was simulated using SYSWELD finite element analysis software. Taking into account nonlinear relationships between temperature and mechanical properties, together with influence of transformation latent heat on temperature field, double ellipsoid heat source model was applied in the simulation of the three fields (temperature field, microstructure field and stress-strain field). Distribution pattern of welding residual stress in 9%Ni steel welded joint was obtained through numerical simulation. Results showed that heat affected zone (HAZ) showing high-level residual stress was the main stress concentrated part of the welded joint. Longitudinal residual stress appeared to be tensile in the weld and HAZ, and compressive in regions remote from the weld. A match of low heat input and high interpass temperature should be employed to lower residual stress level in HAZ. Simulation results were well consistent with theoretical analysis.

Study on Distributed Properties of Welding Residual Stress in Bridge Nodes

2014 ◽  
Vol 501-504 ◽  
pp. 1166-1169
Author(s):  
Jia Liu ◽  
Run Chang Zhang ◽  
Wei Lian Qu ◽  
Li Jiang
Keyword(s):  
Residual Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Source Model ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Heat Source Model ◽  
Lateral Direction ◽  
Welding Procedure ◽  
Welding Direction

The distributed properties of residual stress in bridge nodes have been investigated in the paper. Based on some bridge node, the three dimensional thermodynamics finite element model has been established, meanwhile, the double ellipsoidal distributed heat source model are used to simulate the whole welding procedure of bridge nodes according to the welding parameters. Thus, the distributed regularities of residual stress of bridge node have been obtained. Simulating results show that the residual stresses distribute uniformly in the welding direction, and the max value reaches the yield strength of steel Q345qD. Besides, the residual stress in the lateral direction reaches the max value in the place of welding district, and decreases rapidly when far away from the welds.

Crack Extension Effects on Welding Residual Stress in Fitness for Service Assessment of Crack-Like Defect in Weld

2016 ◽  
Author(s):  
Jeong K. Hong
Keyword(s):  
Residual Stress ◽  
3D Models ◽  
Crack Size ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Element Analysis ◽  
Defect Assessment ◽  
Technical Issues ◽  
Model Geometry ◽  
2D And 3D

The current industry code and standard fitness-for-service assessment (ICS FFSA) procedures ignore the release of the welding residual stress (WRS) in defect assessment of a crack growing in a WRS field. Doing so can result in overly restrictive results in the ICS FFSA of an engineering component. The current ICS FFSA procedures have produced compendiums of WRS distributions and stress intensity factor (SIF) solutions that are characterized by the joint geometry and welding parameters. It is also known that these distributions are based on extensive numerical analyses and provide upper bound estimates; therefore, these types of solutions do not necessarily satisfy the self-equilibrating state. In this investigation, through-wall WRS distributions from the literature data, including measurements and finite element analysis (FEA) results for girth welded pipes, are compared to the representative ICS FFSA WRS procedures. Also, the WRS and SIF solutions using the proposed procedure are compared to those using the ICS FFSA procedures employing 2D and 3D models. From the investigation, it is observed that the ICS FFSA procedures show discrepancies for certain conditions and the levels of conservatism are dependent on the model geometry, boundary constraint condition, crack size, and crack shape. For some cases, the estimations provided from the ICS FFSA procedures are not conservative compared to the reference solutions from literatures and FEA simulations. As a continuous study of the previous investigation [OMAE 2015-41319], the objective of the present paper is to motivate the industry to improve ICS FFSA procedures by clarifying the ambiguous technical issues of crack-like defect assessment in weld regions.

Welding Residual Stresses in Tubular Joints

2013 ◽  
Vol 768-769 ◽  
pp. 605-612 ◽  
Author(s):  
Majid Farajian ◽  
Thomas Nitschke-Pagel ◽  
Klaus Dilger
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Fatigue Crack Initiation ◽  
Welding Residual Stress ◽  
Structural Safety ◽  
Welding Parameters

In spite of an increased awareness of welding residual stress threat to structural integrity, the extent of its influence on fatigue especially under multiaxial loading is still unclear and is a matter of debate. One important reason for this lack of clarities is that the determination of the initial welding residual stress field in welded structures even at the fatigue crack initiation sites is difficult and requires complementary instruments. Since the fatigue crack initiation in sound welds almost always occurs on the surface, the determination of surface residual stresses could increase the awareness of the extent of their threat to the structural safety. In this paper the development of residual stresses in different TIG-welded tubular specimens out of S355J2H and S690QL steel is studied and compared. The mechanisms of the development of residual stresses based on heat input and cooling rate are discussed. The welding parameters and thus heat inputs are varied and the mechanisms leading to different residual stress states are investigated. X-ray method was used for residual stress state characterization.

Numerical Simulation of Weld Metal by Ultra-Narrow Gap Arc Welding

2011 ◽  
Vol 704-705 ◽  
pp. 728-732
Author(s):  
Li Zhao ◽  
Ke Jie Dai ◽  
Fu Ju Zhang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Thick Plate ◽  
Welding Residual Stress ◽  
Narrow Gap ◽  
Welding Temperature ◽  
Welding Joint ◽  
Element Method

The ultra narrow gap welding process is suitable to the thick plate, ultra-thick plate welding with the characteristic of highly effective, high quality, low cost, low energy consumption and so on, and is easy to realize the mechanization and the automation. In this paper, the numerical simulation and technical experiment are used to study the form, grow and distribution regulation of the welding temperature field, stress field in welding joint with UNG MAW. Using the calculation to the thickness of 32mm, an example to simulate the magnitude and distribution of the residual stress in welding joint is given. Research shows that it is an effective analysis method to heat process and mechanic behavior in the welding by using finite element method numerical simulation and few experiments. Keywords: UNG MAW, Welding residual stress, Finite element method, Numerical simulation

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