Investigations on buckling behavior of single-layer reticulated shell with emphasis on considering welding residual stress

2016 ◽  
Vol 60 (6) ◽  
pp. 1181-1190 ◽  
Author(s):  
Zhongwei Zhao ◽  
Han Zhu ◽  
Zhihua Chen
2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Jian-Guo Gong ◽  
Lei Yu ◽  
Feng Wang ◽  
Fu-Zhen Xuan

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.


2019 ◽  
Vol 34 (3-4) ◽  
pp. 57-73
Author(s):  
Nam-Hyok Ri ◽  
Zhihua Chen ◽  
Yong-Sop Ri ◽  
Zhiyao Ma

This article quantitatively evaluated the influence of three-dimensional multi-layer welding on the welding residual stress of super-big diameter welded hollow sphere joint in the large-span spatial steel structure considering the influence of material state change using finite element method. First, this article proposed a conception of equivalent state change time—the virtual time of state change in the analysis of welding and cooling—which represents the heat absorbed or released during the change of solid and fluid states in welding material. The equivalent state change time increases the accuracy of the thermal analysis considering the latent heat of fusion in welding and cooling process. Second, this article simulated the numerical experiments of three welding methods including multi-layer symmetric welding, multi-layer sequential welding, and single-layer symmetric welding, which show that multi-layer symmetric welding not only increases the balance of supporting ability of structure but also decreases the value of maximum tensile residual stress, and it is better than the other two welding methods.


2013 ◽  
Vol 423-426 ◽  
pp. 944-950
Author(s):  
Wei Shen ◽  
Ren Jun Yan ◽  
Lin Xu ◽  
Kai Qin ◽  
Xin Yu Zhang ◽  
...  

This paper uses both numerical simulation method and experimental research method to study on welding residual stress of high-strength steel of the cone-cylinder hull. Welding is often accompanied by a larger welding residual stress, which directly affects the safety and service life of the hull structure. In order to obtain the distribution of the welding residual stress, the welding procedure was developed by its parameter language by using FE analysis software in this paper. Then the welding residual stress of hot spot region was measured through X-ray nondestructive testing method, and compared it with simulation results. Finally, considering the residual stress as the initial stress, this paper analyzed dynamic response process of the welding structure under combined actions of the welding residual stress and multiaxial loads, which could more accurately determine the stress of welding structure and the location of fatigue risk point. According to the amplitude of damage parameters and strain time-history curve, we can estimate the fatigue life of structure by selecting the corresponding damage models.


Author(s):  
Dean Deng ◽  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito

Recent discoveries of stress corrosion cracking (SCC) at nickel-based metals in pressurized water reactors (PWRs) and boiling water reactors (BWRs) have raised concerns about safety and integrity of plant components. It has been recognized that welding residual stress is an important factor causing the issue of SCC in a weldment. In this study, both numerical simulation technology and experimental method were employed to investigate the characteristics of welding residual stress distribution in several typical welded joints, which are used in nuclear power plants. These joints include a thick plate butt-welded Alloy 600 joint, a dissimilar metal J-groove set-in joint and a dissimilar metal girth-butt joint. First of all, numerical simulation technology was used to predict welding residual stresses in these three joints, and the influence of heat source model on welding residual stress was examined. Meanwhile, the influence of other thermal processes such as cladding, buttering and heat treatment on the final residual stresses in the dissimilar metal girth-butt joint was also clarified. Secondly, we also measured the residual stresses in three corresponding mock-ups. Finally, the comparisons of the simulation results and the measured data have shed light on how to effectively simulate welding residual stress in these typical joints.


2014 ◽  
Vol 490-491 ◽  
pp. 594-599
Author(s):  
Fan Ling Meng ◽  
Ai Guo Liu

Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.


2010 ◽  
Vol 107 (5) ◽  
pp. 054904
Author(s):  
Da Xu ◽  
Xuesong Liu ◽  
Ping Wang ◽  
Jianguo Yang ◽  
Wei Xu ◽  
...  

2011 ◽  
Vol 464 ◽  
pp. 627-631
Author(s):  
Jie Zhang ◽  
Ai Hua Sun ◽  
Le Zhu ◽  
Xiang Gu

Welding residual stress is one of the main factors that affect the strength and life of components. In order to explore the effect on residual stress of welding line by laser shock processing, finite element analysis software ANSYS is used to simulate the welding process, to calculate the distribution of welding residual stress field. On this basis, then AYSYS/LS-DYNA is used to simulate the laser shock processing on welding line. Simulation results show that residual stress distributions of weld region, heat-affected region and matrix by laser shock processing are clearly improved, and the tensile stress of weld region effectively reduce or eliminate. The simulation results and experimental results are generally consistent, it offer reasons for parameter optimization of welding and laser shock processing by finite element analysis software.


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