Steel tube - plate connected joint of large crossing transmission towers welding residual stress by numerical simulation

Author(s):  
Yuzhuo Jia ◽  
Liang Zhang
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.


Author(s):  
Tao Mo ◽  
Jingqing Chen ◽  
Pengju Zhang ◽  
Wenqian Bai ◽  
Xiao Mu ◽  
...  

Ultrasonic impact treatment (UIT) is an effective method that has been widely applied in welding structure to improve the fatigue properties of materials. It combines mechanical impact and ultrasonic vibration to produce plastic deformation on the weld joints surface, which introduces beneficial compressive residual stress distribution. To evaluate the effect of UIT technology on alleviating the residual stress of welded joints, a novel numerical analysis method based on the inherent strain theory is proposed to simulate the stress superposition of welding and subsequent UIT process of 304 stainless steel. Meanwhile, the experiment according to the process was carried out to verify the simulation of residual stress values before and after UIT. By the results, optimization of UIT application could effectively reduce the residual stress concentration after welding process. Residual tensile stress of welded joints after UIT is transformed into residual compressive stress. UIT formed a residual compressive stress layer with a thickness of about 0.13 mm on the plate. The numerical simulation results are consistent with the experimental results. The work in this paper could provide theoretical basis and technical support for the reasonable evaluation of the ultrasonic impact on residual stress elimination and mechanical properties improvement of welded joints.


2015 ◽  
Vol 88 ◽  
pp. 1296-1309 ◽  
Author(s):  
Ninshu Ma ◽  
Zhipeng Cai ◽  
Hui Huang ◽  
Dean Deng ◽  
Hidekazu Murakawa ◽  
...  

2011 ◽  
Vol 216 ◽  
pp. 218-222 ◽  
Author(s):  
Wen Li Wang ◽  
Wei Lian Qu ◽  
Jie He

The dynamic stress-strain and welding residual stress during welding are the significant factors which lead to welded cracking and debasement of the joint properties. Therefore, the welding residual stresses are still very importang problems.A large number of guyed mast accidents study shows that the welded joints of earplate and shaft were easily to be destroyed. Therefore, the accurate assessment of the guyed maste earplate joint substructure’s welding residual stress is of great significance. The theory and method of simulation of the welding temperature field and welding stress field by finite element method is first introduced, and then the earplate substructure refine model is established which was up to the welding numerical simulation. Based on ANSYS software’s APDL language to apply the welding heat source load, we can get and save the welding temperature field results at each time. Conversing the thermal analysis element into structure element to finish the caculation of the welding stress field. Eventually by adopting the elimination remnant technology to remove the part of welding residual stresses, we can got the final welding residual stress in different relieving proportion.


2013 ◽  
Vol 546 ◽  
pp. 127-131
Author(s):  
Zhi Qing Guo ◽  
Qiu Juan Lv ◽  
Yan Jiao Li ◽  
Chang Jiang Liu ◽  
Fang Xie

This paper use the software ANSYS to study the aluminum alloy (LF6) welding residual stress by numerical simulation and experimental study. The result indicates that the aluminum alloy (LF6) has the same residual stress distribution with others, there is a maximum value existing at the range of 4-5mm near the welding seam.


2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Yu Sun ◽  
Yun-Fei Jia ◽  
Muhammad Haroon ◽  
Huan-sheng Lai ◽  
Wenchun Jiang ◽  
...  

To understand the residual stress distribution in the welded joints of high density polyethylene (HDPE) pipes is essential to the assessment of its structural integrity. However, limited knowledge of their residual stress was available in this regard. In this paper, the hole-drilling strain-gage method was used to measure the residual stress in the welded seam of HDPE pipes, which was produced by the butt fusion welding technique. The finite element modeling using viscoelastic constitutive model with Prony series was carried out to determine the temperature field and corresponding stress field in the welding stages. The measured residual stress near the surface shows good consistency with the numerical results. It is shown that the residual stress in the hoop direction is much larger than those in the radial and axial directions. The effect of the pipe thickness on the residual stress distribution was also investigated by numerical simulation. The positions of the maximum tensile stress in the welded joints were found within the normalized depth region (the radial depth to the thickness) of 0.2 to 0.8.


2009 ◽  
Vol 3 (3) ◽  
pp. 306-309 ◽  
Author(s):  
Xue-qiu Zhang ◽  
Jian-guo Yang ◽  
Xue-song Liu ◽  
Xu-hui Chen ◽  
Hong-yuan Fang ◽  
...  

2011 ◽  
Vol 295-297 ◽  
pp. 1905-1910 ◽  
Author(s):  
Hai Zhang ◽  
Dong Po Wang ◽  
Sen Li

The welding processes of steel materials are often accompanied by the occurrence of phase transformation. Volume change caused by phase transformation will affect the history of stress and strain. In this article, taking the welding of Q345 as an example, the effects of solid-state phase transformation on the residual stress were investigated by numerical simulation. The values of thermal strain at different temperatures were set to make the volume change caused by phase transformation equivalent as thermal strain. The simulation contained two cases both considering phase transformation and not. The results show that in both two cases the longitudinal stress distribution in the weld zone has almost the same trend. But in the case without considering phase transformation, there is large longitudinal tensile stress concentrating in the weld and HAZ zone and the maximum value is up to 427MPa in the weld. For transverse stress, phase transformation not only changes the value of the stress, but also alters the sign of the stress in the middle of the weld zone. Experiment was also carried out to measure the residual stress by X-ray diffraction. The result considering phase transformation matched much better with the experimental data. It can be concluded that phase transformation in the process of welding has a significant effect on the residual stress and can not be ignored in the numerical simulation of welding.


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