Investigation of Residual Stresses Caused by Welding, Cladding and Tempering of Reactor Pressure Vessels

2003 ◽  
Author(s):  
V. I. Kostylev ◽  
B. Z. Margolin ◽  
A. Y. Varovin ◽  
E. Keim
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Weld Metal ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Reactor Pressure

Calculations of residual stress fields, which arise after welding, cladding and tempering, were performed as applied to reactor pressure vessels (RPVs) of WWER types. These calculations are based on a procedure, which takes into account Feα↔Feγ transformation happening in base and weld metal under welding and cladding, and also creep during tempering. The procedure is based on solutions of the temperature and non-isothermal elasto-plastic problem with and without creep by the finite element method. On the basis of the performed investigation it is shown that Feα↔Feγ transformation may affect the residual stress distribution. An analysis of cases has been performed for which the above effect is strong and for which this effect may be ignored. On the basis of the calculation performed, an engineering procedure is proposed that allows to determine the residual stress fields in welds of the WWER-440 and WWER-1000 for various durations of post-weld tempering.

Prediction of Tablet Characteristics from Residual Stress Distribution Estimated by the Finite Element Method

2013 ◽  
Vol 102 (10) ◽  
pp. 3678-3686 ◽  
Author(s):  
Yoshihiro Hayashi ◽  
Takahiro Miura ◽  
Takuya Shimada ◽  
Yoshinori Onuki ◽  
Yasuko Obata ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
The Finite Element Method ◽  
Element Method

Development of a Program for Predicting Residual Stress Distribution in Multi-Stacked Film

2001 ◽  
Author(s):  
Hyeon Chang Choi ◽  
Jun Hyub Park ◽  
Yong Soo Park
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Prediction Method ◽  
Residual Stress Distribution ◽  
Residual Stress Field ◽  
Finite Element Program ◽  
Polysilicon Film ◽  
Element Method

Abstract The mean stresses of the single and multi-stacked film are experimentally investigated. After stacking several layers on a wafer, we measure the curvature on the wafer. Followed by peeling each layer stacked, we measure the curvature on the wafer, again. Mean residual stresses are calculated from radiuses of the curvatures using the Stoney’s equation[1]. Microcantilever beams is constructed by removing substrate and the deflection at the end of a beam is measured. Finite element method for determining residual stress distribution in multi-stacked films with a multi-step doping process is studied for use in micromachining applications. We propose a finite element program for residual stress analysis (RESA) in multi-stacked polysilicon film. The distribution of residual stress field in multi-stacked films is predicted using RESA. And it is established for the prediction method determining the deflection in a cantilever beam using finite element method (FEM).

Predictions of Residual Stresses in the Mechanical Roll Expansion of HX Tubes Into TEMA Grooves

2003 ◽  
Author(s):  
Dennis K. Williams
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Tube Wall ◽  
Initial Study ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Residual Stress Field ◽  
Steel Tubes

The mechanical roll expansion of heat exchanger tubes into tubesheets containing TEMA grooves, which are thought to aid in the mechanical integrity of the tube-to-tubesheet (TTT)joint, has for many years provided an acceptable means of completing a TTT joint. Inherent with the intentional roll expansion of the tube is the creation of a tensile residual stress field within the tube that is greatest in the transition region between the expanded and unexpanded zones of the tube. An additional complicating factor in the tube-to-tubesheet joint design is the choice of utilizing a seal weld or a “full strength” weld at the tube end in conjunction with a level of roll expansion quantified by the degree of tube wall reduction. This paper presents the results of an initial study of the mechanical roll expansion of 1 inch diameter tubes into a typical TEMA-R designed tubesheet, utilizing two grooves in the tubesheet hole. Two combinations of tube and tubesheet materials are studied that include duplex stainless steel tubes and tubesheet, while the second combination includes type 321 tubes roll expanded into a 2-1/4 Cr-1 Mo tubesheet, clad with 321 SS overlay. The predicted residual stress fields are calculated by the finite element method and employ a simplified two dimension nonlinear axisymmetric model.

Contact Between Vessel Shell and Welded Pad in Nozzle Reinforcement

1993 ◽  
Vol 115 (4) ◽  
pp. 364-372 ◽  
Author(s):  
H. Chen ◽  
Y.-J. Chao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Contact Force ◽  
Thin Shell ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Shell Analysis

In the thin shell analysis of welded pad reinforced nozzles in pressure vessels, no contact between pad and vessel is often assumed. The significance of this contact force to the stress distribution in the structure is little known. In this paper, stress results from the finite element analysis, which includes the contact force between the pad and the vessel, are reported. A comparison of the finite element results with those from thin shell analysis and experiments shows that the finite element method with contact assumption yields improved theoretical prediction for the stress distribution. The effect of both the gap and friction between the pad and the vessel are also investigated.

Residual Stress Distribution Depending on Welding Sequence in Multi-Pass Welded Joints With X-Shaped Groove

1999 ◽  
Vol 122 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Masahito Mochizuki ◽  
Makoto Hayashi ◽  
Toshio Hattori
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Stress Distribution ◽  
Large Diameter ◽  
Residual Stress Distribution ◽  
The Finite Element Method ◽  
Welding Sequence ◽  
Plastic Analysis ◽  
Welded Pipe ◽  
Pipe Joint

Residual stress in a large-diameter multi-pass butt-welded pipe joint was calculated for various welding pass sequences by thermal elastic-plastic analysis using the finite element method. The pipe joint used had an X-shaped groove, and the sequences of welding passes were changed. The distribution of residual stress depends on the welding pass sequences. The mechanism that produces residual stress in the welded pipe joint was studied in detail by using a simple prediction model. An optimum welding sequence for preventing stress-corrosion cracking was determined from the residual stress distribution. [S0094-9930(00)00701-0]

Design of Blind End Closures for High Pressure Vessels

1983 ◽  
Vol 22 ◽  
Author(s):  
A. Chaaban ◽  
K. Leung ◽  
R. J. Pick ◽  
D. J. Burns
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Pressure ◽  
Pressure Vessels ◽  
Central Hole ◽  
Stress Fields ◽  
Elastic Analysis ◽  
The Finite Element Method ◽  
Design Curve ◽  
Plastic Analysis

ABSTRACTThe finite element method has been used to investigate the stress fields in blind end closures of thick-walled pressure vessels. A design curve for choosing end thickness has been developed by elastic analysis of a range of geometries and by elastic-plastic analysis of several geometries. The effects of inner corner radius of the blind end and a small central hole in the end are discussed.

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