Fatigue reliability evaluation of deck-to-rib welded joints in OSD considering stochastic traffic load and welding residual stress

2018 ◽  
Vol 111 ◽  
pp. 151-160 ◽  
Author(s):  
Chuang Cui ◽  
Qinghua Zhang ◽  
Ying Luo ◽  
Hong Hao ◽  
Jun Li
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.


1999 ◽  
Vol 65 (633) ◽  
pp. 989-995 ◽  
Author(s):  
Masahito MOCHIZUKI ◽  
Toshio HATTORI ◽  
Munetoshi ZEN ◽  
Junji YAMAMOTO ◽  
Kimiaki NAKAKADO

2014 ◽  
Vol 496-500 ◽  
pp. 2444-2451
Author(s):  
Qiang Zeng ◽  
Dai Qin Tao ◽  
Zheng Zhou ◽  
Xiao Qian Li

Basing on a giant truss, this passage did a macro assessment of welding resjdual stress by the changes of material hardness which was measured by brinell hardness method after welding. This experiment measured about 1728 measurement points on 72 nodes. Statistical analysis of the hardness data shows that hardness of base metal decreases in the area of HAZ ,and plastic of welded joints increases.


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.


2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940032 ◽  
Author(s):  
Pengfei Zhu ◽  
Guoqing Gou ◽  
Zhaofu Li ◽  
Minhao Zhu ◽  
Zhongyin Zhu ◽  
...  

The welding residual stress has different effects on the mechanical properties of aluminum alloy welded joints, such as size stability, fatigue strength and stress corrosion cracking. Therefore, it is very important to evaluate the welding residual stress accurately. In this paper, the residual stress of A7N01 aluminum alloy welded joints was measured by X-ray diffraction. In contrast to the traditional method, the cos[Formula: see text] method was used in this paper, the results were compared with those obtained by the conventional [Formula: see text] method. In addition, the influence of oscillation unit on the test results of the cos[Formula: see text] method was studied.


2008 ◽  
Vol 575-578 ◽  
pp. 816-820 ◽  
Author(s):  
Guang Tao Zhou ◽  
Xue Song Liu ◽  
Guo Li Liang ◽  
Pei Zhi Liu ◽  
De Jun Yan ◽  
...  

The distribution and value of welding residual stress for 1Cr18Ni9 stainless steel stud welding joints was systemically simulated by ANSYS FE software. The mathematical estimating models of strength of the welded joints were established. Simulation results showed that the welding residual stress was tensile at the edge of the stud, while it was compressive stress at the position near axis center. The largest tensile stress did not exceed yield limit of material. The residual stress had more influence on the strength of welded joints.


2012 ◽  
Vol 557-559 ◽  
pp. 1304-1307 ◽  
Author(s):  
Jing Qiang Zhang ◽  
Jian Guo Yang ◽  
Jia Jie Wang ◽  
Xue Song Liu ◽  
Zhi Bo Dong ◽  
...  

Based on the estimation of the critical hydrogen pressure and concentrations required for hydrogen-induced delayed cracking in high-strength steel, the conclusion that welded joints are hydrogen pressure microcracks body can be drawn under certain conditions. Through the analysis of the relationship between the microstructure evolution of welded joints, diffusion enrichment of hydrogen and cracking behavior, the formation mechanism of hydrogen-induced delayed cracking in weld center of high-strength steel joints is analyzed and the mechanism that stress induced the residual diffusion hydrogen gathered to promote the hydrogen pressure microcracks propagation is proposed. The research shows that the initation and propogation of hydrogen-induced delayed cracking in weld center can be divided into two stages, i.e. irreversible hydrogen damage stage and reversible hydrogen damage stage. In irreversible stage hydrogen pressure is the main causes of the initation of microcracks, while in reversible stage welding residual stress and residual diffusible hydrogen are necessary conditions for microcracks growth. The microcracks growth can be controlled by regulating welding residual stress.


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.


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