A Full-Field Residual Stress Profile Estimation Scheme for Pipe Girth Welds

2012 ◽  
Author(s):  
Shaopin Song ◽  
Pingsha Dong ◽  
Jinmiao Zhang
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stress Distribution ◽  
Stress Profile ◽  
Distribution Characteristics ◽  
Full Field ◽  
Residual Stress Profile ◽  
Weld Toe ◽  
Estimation Scheme ◽  
Girth Welds

For supporting fitness-for-service (FFS) assessment, this paper presents a method for providing a full field description of through-thickness residual stress profiles for pipe girth welds, beyond weld locations (e.g., at weld centerline and weld toe). The paper starts with a brief introduction of the finite element modeling procedure used in this study. Experimental validations are performed for a pipe weld geometry on which detailed experimental data have recently become available in the literature. Then, a large number of parametric residual stress analyses are performed to identify key parameters that govern through-thickness residual stress distribution characteristics. These parameters are not only shown to uniquely contribute to some of the important residual stress distribution characteristics of interest to FFS, but also can be formulated, to the first approximation, using basic mechanics and physics principle. Finally, a detailed application of the proposed full field residual stress estimation scheme is illustrated for various girth weld conditions.

Assessment of Residual Stress Profiles for Fitness for Service Assessment of Pipe Girth Welds

2014 ◽  
Author(s):  
Pingsha Dong ◽  
Shaopin Song ◽  
Jinmiao Zhang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Solution Procedure ◽  
Stress Profile ◽  
Full Field ◽  
Residual Stress Profile ◽  
Estimation Scheme ◽  
Detailed Assessment ◽  
Stress Profiles ◽  
Girth Welds

This paper aims to provide a detailed assessment of some of the existing residual stress profiles prescribed in widely used fitness-for-service assessment codes and standards, such as BS 7910 Appendix Q, by taking advantage of some comprehensive residual studies that become available recently. After presenting a case study on which residual stress measurements are available for validating finite element based residual stress solution procedure, residual stress profiles stipulated in BS 7910 for girth welds are evaluated in the context of a series of parametric finite element results and a shell theory based full-field residual stress estimation scheme. As a result, a number of areas for improvement in residual stress profile development are identified, including some specific considerations on how to attain some of these improvements.

Analysis of Residual Stress Distribution Characteristics at Nozzle Weld in Pressure Vessel and Pipe Components

2019 ◽  
Author(s):  
Shaopin Song ◽  
Pingsha Dong
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Wall Thickness ◽  
Heat Input ◽  
Critical Role ◽  
Residual Stress Distribution ◽  
Thickness Ratio ◽  
Stress Profile ◽  
Distribution Characteristics ◽  
Force Calculation

Abstract In order to achieve a better understanding of residual stress distribution characteristics associated with nozzle welds, this paper focuses on the identification of key parameters that contribute to the development of through-thickness membrane and bending components. This is because, as demonstrated in recent publications by the same authors (Song and Dong, 2016–2017), statically equivalent membrane and bending content in a given residual stress distribution play a far more critical role in fracture driving force calculation in Fitness-for-Service (FFS) assessment. To do so, a recent detailed investigation to residual stress distributions in nozzle welds is presented in this paper, covering nozzle radius to wall thickness ratio from 2 to 50, heat input from 400 J/mm to 1000 J/mm, weld joint types including set-in nozzle weld and set-on nozzle weld. By means of a residual stress decomposition technique, controlling parameters that govern through-thickness membrane and bending stresses have been identified, which are nozzle radius to wall thickness ratio (r/t) and linear heat input parameter (Q). Then, a unified functional form for representing through-thickness residual stress profile in nozzle weld is presented for supporting fitness for service assessment, e.g., by means of API 579-RP.

A Study on the Residual Stress and Fracture Behavior of Pipeline Girth Welds Joining Pipes of Different Strength

2010 ◽  
Author(s):  
Woo-sik Kim ◽  
Jong-hyun Baek ◽  
Choel-man Kim ◽  
Young-pyo Kim
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Material Property ◽  
Fracture Behavior ◽  
Residual Stress Distribution ◽  
Element Analysis ◽  
Weld Region ◽  
Similar Materials ◽  
Base Strength ◽  
Girth Welds

The following cases of girth welded region between pipelines having different base strength were considered. The pipeline shows different fracture behavior from girth welded pipeline between similar materials due to strength mismatch and residual stress distribution. Investigation about the residual stress distribution and fracture behavior of pipeline having girth welds of the differnet base metals (X70/X65 and X70/X42) with different material property has performed using finite element analysis. The effect of mismatched material property on girth weld region is negligible when shape of pipeline is similar. The assessment for occurance of crack on girth weld region with pipes with material property mismatched can be replaced by that of the similar pipes with low strength on the point view of conservation.

Residual Stress Profiles of Pipe Girth Weld Using a Stress Decomposition Method

2014 ◽  
Author(s):  
Huaguo Teng ◽  
Steve Bate
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Heuristic Method ◽  
Measurement Data ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Components ◽  
Stress Profiles ◽  
Girth Welds

The application of procedures such as R6 or BS7910 for the structural assessment of defects in pressurised components containing residual stresses requires knowledge of the through-wall residual stress profile. Currently there is much interest in improving the residual stress profiles that are provided in the procedures. In this paper we present an improved analysis of residual stresses of the pipe girth welds by applying the developed heuristic method to one set of extended residual stress measurement data. The through-thickness residual stress is decomposed into three stress components: membrane, bending and self-equilibrating. The heuristic method was applied to the three components separately, so that the residual stress profile was a combination of the three stress components. This form provides not only a clear physical basis for the residual stress profile, but is also convenient for defect assessment where only the membrane and bending stress components are important.

A Residual Stress Profile Estimation Method for Narrow Groove Girth Welds

2018 ◽  
Author(s):  
Shaopin Song ◽  
Pingsha Dong
Keyword(s):  
Residual Stress ◽  
Wall Thickness ◽  
Estimation Method ◽  
Pressure Vessels ◽  
Thickness Ratio ◽  
Stress Profile ◽  
Stress Distributions ◽  
Narrow Gap ◽  
Residual Stress Profile ◽  
Girth Welds

A recent comprehensive investigation into residual stress distributions in narrow gap welds in pressure vessels and pipe components are presented in this paper, covering component wall thickness from 1” (25.4mm) to 10” (254mm), component radius to wall thickness ratio from 2 to 100, and linear welding heating input from low (300 J/mm) to high (18000 J/mm). By means of a residual stress decomposition technique, two key parameters that govern through-thickness residual stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density (Q̂) having a unit of J/mm3. With these two parameters, a unified functional form for representing through-thickness residual stress profile in narrow gap welds is proposed for supporting fitness for service assessment, e.g., using f API 579-RP. Its validity is further confirmed by full-blown thermomechanical finite element residual stress analyses for a number of selected narrow gap weld cases.

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