A Probabilistic Evaluation Model for Welding Residual Stress Distribution at Piping Joint in Probabilistic Fracture Mechanics Analysis

2008 ◽  
Author(s):  
Hiroto Itoh ◽  
Jinya Katsuyama ◽  
Kunio Onizawa
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Failure Probability ◽  
Evaluation Model ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Probabilistic Fracture Mechanics ◽  
Probabilistic Evaluation ◽  
Aging Knowledge

Stress corrosion cracking (SCC) has been observed at some piping joints made by Austenitic stainless steel in BWR plants. In JAEA, we have been developing probabilistic fracture mechanics (PFM) analysis methods for aged piping based on latest aging knowledge and an analytical code, PASCAL-SP. PASCAL-SP evaluates the failure probability of piping at aged welded joints under SCC by a Monte Carlo method. We proposes a simplified probabilistic model which can be applied to the failure probability analysis based on PFM for welded joint of piping considering the uncertainty of welding residual stress. And the probabilistic evaluation model is introduced to PASCAL-SP. A parametric PFM analysis concerning uncertainties of residual stress distribution using PASCAL-SP was performed. The PFM analysis showed that the uncertainties of residual stress distribution largely influenced break probability. The break probability increased with increasing the uncertainties of residual stress.

Accounting for Constraint in Probabilistic Fracture Mechanics Analysis of Welds in Floating Production, Storage and Off-Loading (FPSO) Vessels

2003 ◽  
Author(s):  
Jens P. Tronskar
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
North Sea ◽  
Failure Probability ◽  
Crack Tip ◽  
Probabilistic Fracture Mechanics ◽  
Crack Tip Constraint

Revision 4 of the British Energy R6 document: “Assessment of the integrity of structures containing defects” provides methods to allow for loss of crack tip constraint for shallow weld flaws. The document also provides methods to estimate upper-bound values of the through thickness residual stress distribution for a range of common weld joint configurations. The present paper presents results of analyses where approaches to modify the R6 Option 1 or 2 failure assessment diagrams (FADs) for loss of crack tip constraint pertaining to primary and non-uniform residual stress have been applied. The modified FAD were formulated for probabilistic fracture mechanics analyses of semi-elliptical surface cracks located at transverse deck welds of Floating Production, Storage and Off-loading (FPSO) vessels designed to operate in the North Sea. The objective was to study the influence on the failure probability of modifying the FAD for constraint and allowing for non-uniform residual stress. Another objective was to study the influence of constraint correction on the combined fatigue and fracture failure probability for the vessels subjected to wave loading. Material and weld tensile properties and fracture toughness distributions for input to the probabilistic fracture mechanics analyses were obtained from testing of welded panels prepared using welding procedures for actual FPSO fabrication. The loading conditions were derived based on North Sea wave data pertaining to the offshore field where the FPSO is operating. The stresses were obtained from global FE analysis and fitted Weibull long-term and extreme value distributions. The results of the analyses demonstrate clearly the importance of correcting for crack tip constraint pertaining to both primary and secondary stress and to allow for non-uniform residual stress for shallow surface flaws of known crack heights. However, in combination with fatigue crack growth the effects become less prominent as the failure probability is governed by the uncertainty in the parameters of the crack growth relationship and the long-term stress distribution.

Effects of Flange Width Ratio on the Residual Stresses in Welded Monosymmetric I-Section

2014 ◽  
Vol 501-504 ◽  
pp. 574-577
Author(s):  
Zhuang Nan Zhang ◽  
Xin Zhao ◽  
Ya Nan Zhao
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Width Ratio ◽  
Residual Tensile Stress ◽  
Growth Trend ◽  
Finite Element Software ◽  
Compressive Stresses ◽  
Peak Value

This paper used ANSYS finite element software to simulate the residual stress of the welded monosymmetric I-section and obtain residual stress distribution curves, analyzed the influence of flange width ratio on welding residual stress peak value and the stress distribution. The studies have shown that: with the flange width ratio decrease gradually, peak value of residual stress in flange and web is to increase; peak value of residual tensile stresses in both flange and web close to the steel yield strength fy, peak value of residual compressive stresses is 0.4fy in wide flange and the web near wide flange and in narrow flange and web near narrow flange is 0.3fy; the distribution of the residual tensile stress in the flange and web have growth trend.

Research on the Residual Stress of Aluminum Alloy (LF6) Welding

2013 ◽  
Vol 546 ◽  
pp. 127-131
Author(s):  
Zhi Qing Guo ◽  
Qiu Juan Lv ◽  
Yan Jiao Li ◽  
Chang Jiang Liu ◽  
Fang Xie
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Experimental Study ◽  
Aluminum Alloy ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Welding Seam ◽  
Maximum Value

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.

Welding Residual Stress in HDPE Pipes: Measurement and Numerical Simulation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Yu Sun ◽  
Yun-Fei Jia ◽  
Muhammad Haroon ◽  
Huan-sheng Lai ◽  
Wenchun Jiang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Distribution ◽  
Welded Joints ◽  
Residual Stress Distribution ◽  
Fusion Welding ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Radial Depth ◽  
Hdpe Pipes

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.

A method for the measurement of residual stresses using a fracture mechanics approach

1989 ◽  
Vol 24 (1) ◽  
pp. 23-30 ◽  
Author(s):  
K J Kang ◽  
J H Song ◽  
Y Y Earmme
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
The State ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Simple Method

A simple method for measuring residual stresses in a plate is described. In this method residual stresses are evaluated using a fracture mechanics approach, that is, the strains or displacements measured at a point on the edge of a plate as a crack is introduced and extended from the edge are used to deduce the state of stresses that existed in the uncracked plate. Through finite element analyses and experiments this method is shown to be valid and effective for measuring the two-dimensional residual stress distribution of a welded plate.

Numerical Simulation on Residual Stress Distribution of the Pipe-Plate Welding

2009 ◽  
Vol 417-418 ◽  
pp. 937-940
Author(s):  
Li Li ◽  
Ren Fu Wang ◽  
Gang Xue ◽  
Xiang Jun Min
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Axial Stress ◽  
Three Dimensional ◽  
Good Method ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Accurate Estimation ◽  
Element Analysis ◽  
Plate Structure

The pipe-plate welding is a common type of joint in almost all industries. However the presence of residual stresses can be detrimental to the performance of the welded product. Therefore a good method for accurate estimation of the welding residual stress is needed. In this paper, three-dimensional finite element analysis is carried out to simulate pipe-plate structure. Based on the ANSYS software, the residual stress distribution of the pipe-plate structure during welding and after welding is predicted. The calculation results show that the residual stress of weld bead is higher than other places. The radial stress, hoop stress and axial stress are not significantly sensitive to the angle.

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