2110 Estimation of the Residual Stress of a Bolt Thread Root Induced by Thread Rolling : Application of 3-D FE analysis for the Groove-Rolled Specimen

For decades, the PWSCC on the penetration nozzles like BMI and CEDM nozzles are widely occurred all around the world. The PWSCC is dependent on the tensile stress condition, specific materials and chemical environment. Therefore, to evaluate the severity of the PWSCC, prediction of the welding residual stress on the J-groove welding part in the penetration nozzles is essential. Residual stress can be measured by using experimental methods like deep-hole drilling and X-ray diffraction, etc. However, the results of experimental methods are quite doubtable and these methods are hard to apply on the actual equipment. Therefore, computational approach like the FE analysis has been considered. The FE analysis results are very sensitive to the FE model density and analysis conditions. In this paper the optimized FE model for the residual stress analysis will be developed in the case of CEDM penetration nozzle. The optimized parameters contains bead number and mesh density. The bead numbers along the longitudinal and circumferential directions are considered and the mesh density in each the bead is also considered. The model will be verified by numerical error control.

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Effects of Residual Stress on Elastic Plastic Behavior of Metallic Glass Bolts Formed by Cold Thread Rolling

Journal of the Japan Society for Technology of Plasticity ◽

10.9773/sosei.54.426 ◽

2013 ◽

Vol 54 (628) ◽

pp. 426-430

Author(s):

Shigeru YAMANAKA ◽

Kenji AMIYA ◽

Yasunori SAOTOME

Keyword(s):

Residual Stress ◽

Metallic Glass ◽

Plastic Behavior ◽

Elastic Plastic ◽

Thread Rolling

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

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2018-85076 ◽

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.

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The Effect of Welding-Pass Grouping on the Prediction Accuracy of Residual Stress in Multipass Butt Welding

Mathematical Problems in Engineering ◽

10.1155/2017/7474020 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13

Author(s):

Jeongung Park ◽

Gyubaek An ◽

Sunghoon Kim

Keyword(s):

Residual Stress ◽

Diffraction Method ◽

Fe Analysis ◽

Computer Memory ◽

Butt Weld ◽

Butt Welding ◽

Welded Structure ◽

Welding Sequence ◽

Grouping Method ◽

Neutron Diffraction Method

The residual stress analysis of a thick welded structure requires a lot of time and computer memory, which are different from those in thin welded structure analysis. This study investigated the effect of residual stress due to welding-pass grouping as a way to reduce the analysis time in multipass thick butt welding joint. For this purpose, the parametric analysis which changes the number of grouping passes was conducted in the multipass butt weld of a structure with a thickness of 25 mm and 70 mm. In addition, the residual stress by thermal elastoplastic FE analysis is compared with the results by the neutron diffraction method for verifying the reliability of the FE analysis. The welding sequence is considered in order to predict the residual stress more accurately when using welding-pass grouping method. The results of the welding-pass grouping model and half model occurred between the results of the left/right of the full model. If the total number of welding-pass grouping is less than half of that of welding pass, a large difference with real residual stress is found. Therefore, the total number of the welding-pass grouping should not be reduced to more than half.

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Study on Evaluation Procedure for Calculating the Stress Intensity Factor of Flaws Beneath RPV Cladding During Pressurised Thermal Shock Events by FE Analysis

Volume 1B: Codes and Standards ◽

10.1115/pvp2016-63210 ◽

2016 ◽

Author(s):

Hiroyuki Sakamoto ◽

Takatoshi Hirota ◽

Naoki Ogawa

Keyword(s):

Residual Stress ◽

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Thermal Shock ◽

Alloy Steel ◽

Fe Analysis ◽

Welding Residual Stress ◽

Low Alloy Steel ◽

Elastic Plastic

Elastic-plastic finite element (FE) analysis is performed to determine the plastic behavior of the reactor pressure vessel (RPV) inner surface caused by rapid cooling during pressurized thermal shock (PTS) events. However, as the J-integral is not path-independent for elastic-plastic material in the unloading process, it is necessary to apply a suitable correction method using elastic material. In addition, it is also necessary to consider the effect of the welding residual stress appropriately. Therefore, we investigated the stress intensity factor derived from FE analysis based on a model consisting of elastic-plastic cladding and linear elastic low-alloy steel with subsequent plastic zone correction, since the stress level of low-alloy steel remains within the elastic region except the crack front during a PTS event. Furthermore, we examined whether the stress mapping method is applicable for reflecting the effect of welding residual stress in FE analysis, even though the plastic strain generated during welding is ignored.

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