Engineering J Estimation Equations for Spent Fuel Canisters Under Combined Mechanical and Welding Residual Stresses

2018 ◽  
Author(s):  
Hyun-Jae Lee ◽  
Jae-Yoon Jeong ◽  
Yun-Jae Kim ◽  
Poh-Sang Lam
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Fe Analysis ◽  
Welding Residual Stress ◽  
Spent Fuel ◽  
Basic Form ◽  
Estimation Equations ◽  
Reference Stress ◽  
J Estimation

This paper provides engineering J estimation equations for Spent Fuel Canisters (SFCs) under combined mechanical and welding residual stress (WRS) fields. The basic form of estimation equations is reference stress-based ones as in R6. Interaction between mechanical (primary) and residual (secondary) stresses is treated using the V-factor. Based on systematic finite element (FE) analysis and J results, the V-factors for the combined mechanical and welding residual stresses are reported.

Engineering J Estimates for Spent Fuel Canisters Under Combined Mechanical and Welding Residual Stresses

2019 ◽  
Author(s):  
Hyun-Jae Lee ◽  
Yun-Jae Kim ◽  
Poh-Sang Lam ◽  
Robert L. Sindelar
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Fe Analysis ◽  
Welding Residual Stress ◽  
Spent Fuel ◽  
Reference Stress ◽  
Fracture Assessment

Abstract This paper compares engineering J estimates for Spent Fuel Canisters (SFCs) under combined mechanical and welding residual stress (WRS) with finite element (FE) results. Engineering J estimates are based on reference stress method provided in the R6 procedure considering interaction between primary and secondary stresses using the V-factor. It is found that residual stress should be considered in fracture assessment and the R6 estimates are reasonably conservative compared to FE analysis results.

Finite Element Analysis of Welding Residual Stress of the Ultra-Thick 13MnNiMoR Steel Cylinder of a Large EO Reactor Made in China

2013 ◽  
Author(s):  
Yongbin Wen ◽  
Luyang Geng ◽  
Jianming Gong ◽  
Yangfei Wang ◽  
Shantung Tu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Fe Analysis ◽  
Welding Residual Stress ◽  
Inside Surface ◽  
Stress Distributions ◽  
Steel Cylinder ◽  
Made In China ◽  
Made In

The finite element (FE) analysis was applied to investigate welding residual stresses generated in the weld region of the ultra-thick 13MnNiMoR steel cylinder of a large Ethylene Oxide (EO) reactor made in China, with an outer diameter of 6760mm and wall thickness of 110mm. The FE Analysis consists of the nonlinear thermal and thermo-mechanical axisymmetric numerical simulations. In the FE analysis, an alternating welding model was created for the double U-type groove welding. The residual stress distributions on the inside surface and the outside surface were obtained. The analyzed results show that the axial and hoop welding residual stresses on the inside surface and the outside surface are tensile in the weld zone and its vicinity. The residual stress distributions on the inside surface and the outside surface are very sensitive to the distance from the weld centerline. The effects of the temperature of PWHT on the welding residual stress were analyzed by taking into account PWHT at 600 °C, 620 °C and 640 °C. The simulated results show the residual stresses decrease with the increase in the temperature of PWHT, and an appropriate temperature of PWHT is 620 °C for the ultra-thick cylinder of the domestic EO reactor.

scholarly journals Investigation of Clamping Effect on the Welding Residual Stress and Deformation of Monel Plates by Using the Ultrasonic Stress Measurement and Finite Element Method

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Yashar Javadi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Acoustic Waves ◽  
Stress Measurement ◽  
Fe Analysis ◽  
Ultrasonic Waves ◽  
Welding Residual Stress ◽  
Longitudinal Residual Stress ◽  
Ultrasonic Stress Measurement

Welding of nickel-based alloys is increasingly used in the industry to manufacture many important components of the marine industries, chemical processing, etc. In this study, a 3D thermomechanical finite element (FE) analysis is employed to evaluate residual stresses and deformations caused by the tungsten inert gas (TIG) welding of Monel 400 (Nickel-Copper alloy) plates. The FE results related to the residual stresses and deformations have been verified by using the hole-drilling stress measurement and common dimensional measurement tools, respectively. Residual stresses analyzed by the FE simulation are then compared with those obtained from ultrasonic stress measurement. The ultrasonic stress measurement is based on acoustoelasticity law, which presents the relation between the acoustic waves and the stress of material. The ultrasonic stress measurement is carried out by using longitudinal critically refracted (LCR) waves which are longitudinal ultrasonic waves propagated parallel to the surface inside the tested material. Two welded plates are experimentally prepared (with and without using clamp) to investigate the clamping effect on the welding residual stress and deformations. By utilizing the FE analysis along with the LCR method, the distribution of longitudinal residual stress could be achieved. It has been concluded that the applied methodologies are enough accurate to distinguish the clamping effect on the welding residual stresses and deformations of Monel plates.

scholarly journals Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction

2006 ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welding Process ◽  
Pressure Vessels ◽  
Welding Residual Stress ◽  
Stress Distributions ◽  
Multipass Welding ◽  
Hexahedral Elements ◽  
Element Removal

Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full 3D thermo-mechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weldline on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting 3D through thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.

scholarly journals Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction

2006 ◽  
Vol 129 (4) ◽  
pp. 601-608 ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Pressure Vessels ◽  
Welding Residual Stress ◽  
Stress Distributions ◽  
Multipass Welding ◽  
Hexahedral Elements ◽  
Element Removal

Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage, which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full three dimensional thermomechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry, and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weld line on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting three dimensional through-thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.

Prediction of Residual Stress Distributions in Welded Sections of P92 Pipes with Small Diameter and Thick Wall based on 3D Finite Element Simulation

2015 ◽  
Vol 34 (3) ◽  
Author(s):  
Xiaowei Wang ◽  
Jianming Gong ◽  
Yanping Zhao ◽  
Yanfei Wang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Small Diameter ◽  
Fe Analysis ◽  
Thick Wall ◽  
Fe Model ◽  
Stress Distributions ◽  
Residual Stress Field ◽  
Heat Treated

AbstractThis study used ABAQUS finite element (FE) software to investigate the residual stress distributions of P92 welded pipes in both the as-weld and post weld heat treated (PWHT) condition. Sequential coupling quasi-static thermo-mechanical in conjunction with moving double ellipsoidal heat source and an element add/remove technique to simulate deposition of new weld material, are combined in the 3D FE analysis. To validate the simulation results, the residual stresses in axial direction at the surface of pipe were measured by X-ray diffraction technique and compared with the results of FE analysis. Detailed characteristic distributions of the residual stresses are discussed. Results show that the FE model can predict the residual stress distributions satisfactorily. Highest residual stresses on the outer surface are found in the last weld bead to be deposited. And the highest tensile residual stress for the full welded section take place in heat affected zone (HAZ) near the middle thickness. Larger residual sstress can be found around the welding start point along the pipe circumference. Comparison of heat treated specimen and untreated specimen illustrates that PWHT has a strong effect on the residual stress field.

Application of 3D Finite Element Modelling to Repair Weld Simulation in Industrial Applications

2002 ◽  
Author(s):  
George Vinas ◽  
Tamba Dauda ◽  
Nicola Moyes ◽  
Alan Laird
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Measurement Techniques ◽  
Fem Simulation ◽  
Welding Process ◽  
Industrial Applications ◽  
Welding Residual Stress ◽  
Experimental Techniques ◽  
Residual Stress Field

The Finite Element Method (FEM) has been implemented in 3D to predict welding residual stresses in repair welds. The analysis has been used to achieve more accurate residual stress predictions for the weld at the cost of long computation times. The use of this CPU intensive approach has been facilitated by the advent of ever-faster computer processors being made more accessible to the engineering community. The same technique has also been used with coarser meshes involving simplified welding sequences where a number of weld passes are “lumped” together to reduce the simulation time. The authors argue that this latter approach can be very useful in predicting the more global component response — in cases where 2D model symmetries are not applicable — and for rapid identification of problem areas where finer simulations would be prohibitive. The authors show an example of a residual stress prediction for a letterbox repair obtained using the FEM. Good agreement between this prediction and experimental measurements is shown. The FEM simulation technique has been used to predict residual stress formation during the welding process and subsequent service loading of the component. This analysis shows the residual stress field relaxation following “shakedown”. The component under service conditions is subjected to pressure loading and a small amount of bending stress. Based on recent residual stress experimental programmes conducted at Mitsui Babcock Energy Limited (MBEL), the authors provide a brief discussion on the ways in which various experimental techniques have been used to verify welding residual stress predictions from FE. The authors argue that just as there has been an interest in the field to measure residual stresses in the highly stressed regions of a weld, it is equally important to measure stresses in areas of relatively low stress to confirm that stresses do indeed die out away from welds. It is in the latter case where some experimental techniques cannot perform as well as other simple, well proven, strain measurement techniques.

FEA Welding Residual Stress and Fracture Mechanics Model for Nozzles With J-Groove Attachment Welds: Methodology and Application

2004 ◽  
Author(s):  
John E. Broussard ◽  
E. Stephen Hunt ◽  
Glenn A. White
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fracture Mechanics ◽  
Residual Stresses ◽  
Model Development ◽  
Welding Residual Stress ◽  
Element Analysis ◽  
Mechanics Model ◽  
Modeling Techniques ◽  
Reactor Pressure

Residual stresses due to welding in reactor pressure vessel (RPV) top head nozzle penetrations have been predicted using finite element analysis since the early 1990s. While the analyses were originally targeted at calculating nozzle stresses, the finite element methods have been extended to model a number of different aspects of RPV head penetrations. Both top and bottom head penetrations have been modeled, and the effects of J-groove butter weld deposition and subsequent thermal stress relief of the top head are now included in the analytical model. Development work has recently been completed to integrate a fracture mechanics model into the welding residual stress model. This has allowed for the prediction of crack tip stress intensity factors in the presence of welding residual stresses that include the effects of stress redistribution due to the presence of the crack. This paper presents some of the modeling techniques used in these recent analyses, and some key results obtained.

scholarly journals Residual Stress Measurements in Mo/CuCrZr Tiles Using Neutron Diffraction

2008 ◽  
Vol 59 ◽  
pp. 299-303
Author(s):  
K. Mergia ◽  
Marco Grattarola ◽  
S. Messoloras ◽  
Carlo Gualco ◽  
Michael Hofmann
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Heat Sink ◽  
High Yield ◽  
Fusion Reactors ◽  
Plasma Facing Components ◽  
Induced Stresses ◽  
Compliant Layer

In plasma facing components (PFC) for nuclear fusion reactors tungsten or carbon based tiles need to be cooled through a heat sink. The joint between the PFC and the heat sink can be realized using a brazing process through the employment of compliant layer of either a low yield material, like copper, or a high yield material, like molybdenum. Experimental verification of the induced stresses during the brazing process is of vital importance. Strains and residual stresses have been measured in Mo/CuCrZr brazed tiles using neutron diffraction. The strains and stresses were measured in Mo tile along the weld direction and at different distances from it. The experimental results are compared with Finite Element Simulations.

Finite Element Analyses of Residual Stresses in Typical Welded Joints Used in Nuclear Power Plants and Comparisons With Experiments

2010 ◽  
Author(s):  
Dean Deng ◽  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joints ◽  
Nuclear Power ◽  
Power Plants ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Dissimilar Metal ◽  
Water Reactors

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.

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