RSE-M - ASME XI - API 579: Comparison of Failure Assessment Diagrams (FAD)

2018 ◽  
Author(s):  
Claude Faidy
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Elastic Stress ◽  
Short Review ◽  
The Other ◽  
Ductile Tearing ◽  
Reference Stress ◽  
Failure Assessment ◽  
Tearing Resistance ◽  
Applied Stresses

After a short review of the 3 Codes in term of flaw evaluation, this paper will consider the Failure Assessment Diagrams (FAD) proposed in each of them. The cracked components are evaluated by a dedicated diagram for margin evaluation of ductile tearing resistance of the components: the elastic stress intensity factor of the crack normalized by the toughness of the material on one axis and the applied stresses normalized by a Reference Stress in the other axis. The 2017 Edition of RSE-M Appendix 5.4 and 5.6, the 2017 Edition of ASME XI Appendix H and the 2016 Edition of API 579 Part 9 will be used in this first comparison.

Slow Crack Growth in Glasses and Ceramics Under Residual and Applied Stresses

1989 ◽  
Vol 111 (1) ◽  
pp. 61-67 ◽  
Author(s):  
F. Erdogan
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Residual Stresses ◽  
Crack Growth ◽  
Slow Crack Growth ◽  
Threshold Value ◽  
Crack Arrest ◽  
Growing Crack ◽  
Applied Stresses

The problem of slow crack growth under residual stresses and externally applied loads in plates is considered. Even though the technique developed to treat the problem is quite general, in the solution given it is assumed that the plate contains a surface crack and the residual stresses are compressive near and at the surfaces and tensile in the interior. The crack would start growing subcritically when the stress intensity factor exceeds a threshold value. Initially the crack faces near the plate surface would remain closed. A crack-contact problem would, therefore, have to be solved to calculate the stress intensity factor. Depending on the relative magnitudes of the residual and applied stresses and the threshold and critical stress intensity factors, the subcritically growing crack would either be arrested or become unstable. The problem is solved and examples showing the time to crack arrest or failure are discussed.

Comparison Between API 579-1/ASME FFS-1 and ASME VIII Division 3 Stress Intensity Factor Solutions Used for Fracture Mechanics and Fatigue Analysis of Thick Walled Cylinders

2008 ◽  
Author(s):  
Jan G. M. Keltjens
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Life Time ◽  
Time Study ◽  
Worked Example ◽  
Failure Assessment ◽  
Section Viii ◽  
Burst Analysis

The paper discusses the differences between API 579-1/ASME FFS-1-1/ASME FFS-1 [1] and ASME Section VIII Division 3 [2] stress intensity factor solutions. In addition to this, the use of the Failure Assessment Diagram (FAD) in leak before burst analysis is compared to the present Division 3 approach. The paper contains the background of both approaches and a worked example demonstrating the effect of both methods. Finally, a simplified fatigue crack growth based life time study is presented.

A Study of the Stress Intensity Factor and Crack Opening Displacement Relationship Between Uniform Thickness Pipe Bends and Non-Uniform Thickness Pipe Bends

2016 ◽  
Author(s):  
Kyung-Dong Bae ◽  
Chul-Goo Kim ◽  
Seung-Jae Kim ◽  
Hyun-Jae Lee ◽  
Yun-Jae Kim
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Opening Displacement ◽  
Elastic Stress ◽  
Crack Opening ◽  
Radius Of Curvature ◽  
Uniform Thickness ◽  
Opening Displacement ◽  
Thickness Variations

This paper proposes the relationship of stress intensity factor and crack opening displacement between pipe bends with uniform thickness and those with non-uniform thickness. In actual case, pipe bends have thickness variations. Unlike typical pipe bends, heat induction bend pipes have significant thickness variations (non-uniform thickness) because of manufacturing process. When the ratio of radius of curvature and pipe radius is 3 for heat induction bend pipes, the thickness at intrados and extrados can be calculated by 1.75 times and 0.875 times of nominal thickness which is original thickness before manufacturing process, respectively. In this situation, it is difficult to apply existing elastic stress intensity factor and crack opening displacement results [1, 2] and it is essential to modify existing solution or to create new solution. In this paper, to find effect of pipe bends thickness variation, 90° through-wall cracked pipe bends with not only uniform thickness but also non-uniform thickness are considered. The ratios of radius and thickness are 5, 10 and ratios of pipe radius of curvature and radius are 3, 4 and 5. Loading condition is in-plane opening bending for intrados crack and closing bending for extrados crack. The through-wall crack sizes are 12.5%, 25% and 37.5% of circumferential cross section. Material of pipe bends is assumed to follow elastic behavior. The proposal is made by extensive finite elements analyses using ABAQUS [3], predicted elastic stress intensity factors for pipe bends with non-uniform thickness are compared with finite element results. The results show a good agreement. It may be useful to calculate elastic stress intensity factor for bends with non-uniform thickness without complex modeling and finite analyses.

scholarly journals Comparison of BS 7910 and API 579-1/ASME FFS-1 Solutions With Regards to Leak-Before-Break

2016 ◽  
Author(s):  
Renaud Bourga ◽  
Bin Wang ◽  
Philippa Moore ◽  
Yin Jin Janin
Keyword(s):  
Experimental Data ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Material Properties ◽  
Crack Opening ◽  
Surface Cracks ◽  
Not Given ◽  
Reference Stress ◽  
The Common ◽  
Leak Before Break

One of the ways to aid the decision whether or not to live with defects in pressurised components is through the demonstration of Leak-Before-Break (LBB). In this paper, three of the main solutions to carry out the LBB assessment, namely Stress Intensity Factor (SIF), Reference Stress (RS) and Crack Opening Area (COA) have been evaluated and compared for both BS 7910 and API 579/ASME FFS-1 standards. Differences with respect to the choice of solutions and boundary conditions are illustrated and discussed. The same applied loads and material properties have been used when applying each procedure. Different geometries for potential pressurised components which are of interest with regards to LBB have been considered for each solution. Focus is made on cylinders where axially and circumferentially oriented through-wall and surface cracks were analysed. While SIF solutions produce similar results for both standards, reference stress solutions show greater differences in the results. However, in LBB assessments it is the reference stress solution which is more relevant, since most LBB assessments pre-suppose the material to be ductile. In terms of COA, solutions are not given exactly equivalent, however they seem to agree well within the common range of applicability. Differences in the assessment route between the standards is also discussed. Experimental data from literature has also been compared to the different standard predictions, to illustrate the accuracy of the solutions for axially oriented surface cracks. The ability of solutions to predict the boundary between leak and break is discussed, in relation to how this shows the level of conservatism.

Guidance on a Defect Interaction Effect for In-Plane Surface Cracks Using Elastic Finite Element Analyses

2008 ◽  
Author(s):  
Nam-Su Huh ◽  
Suhn Choi ◽  
Keun-Bae Park ◽  
Jong-Min Kim ◽  
Jae-Boong Choi ◽  
...  
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Interaction Effect ◽  
Elastic Stress ◽  
Plane Surface ◽  
Surface Cracks ◽  
Defect Interaction

The crack-tip stress fields and fracture mechanics assessment parameters, such as the elastic stress intensity factor and the elastic-plastic J-integral, for a surface crack can be significantly affected by adjacent cracks. Such a defect interaction effect due to multiple cracks can magnify the fracture mechanics assessment parameters. There are many factors to be considered, for instance the relative distance between adjacent cracks, crack shape and loading condition, to quantify a defect interaction effect on the fracture mechanics assessment parameters. Thus, the current guidance on a defect interaction effect (defect combination rule), including ASME Sec. XI, BS7910, British Energy R6 and API RP579, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates a defect interaction effect by evaluating the elastic stress intensity factor of adjacent surface cracks in a plate along the crack front through detailed 3-dimensional elastic finite element analyses. The effects of the geometric parameters, the relative distance between cracks and the crack shape, on the stress intensity factor are systematically investigated. As for the loading condition, only axial tension is considered. Based on the elastic finite element results, the acceptability of the defect combination rules provided in the existing guidance was investigated, and the relevant recommendations on a defect interaction for in-plane surface cracks in a plate were discussed.

Emerging Technology in Fitness-for-Service Assessment of Crack-Like Flaws

2019 ◽  
Author(s):  
Ted L. Anderson
Keyword(s):  
Stress Intensity ◽  
Element Analysis ◽  
Reference Stress ◽  
Future Edition ◽  
Failure Assessment ◽  
Complex Shapes ◽  
Constraint Effects ◽  
New Equation ◽  
Definition Of ◽  
Flaw Shape

Abstract This paper describes several recent advances in crack assessment technology that have been or will be incorporated into the API 579 fitness-for-service standard. Four technology areas are addressed herein: • Stress intensity factor solutions. The 2016 edition of API 579 contains an extensive library of stress intensity solutions inferred from 3D finite element analysis. • A new equation for fitting elastic-plastic J solutions. A parametric equation that captures the elastic, fully-plastic and contained-yielding regimes of deformation provides an alternative definition of reference stress in the failure assessment diagram (FAD) method. • An enhanced constraint adjustment. A future edition of API 579 will include an improved version of the Wallin methodology for shifting the Master Curve reference temperature to account for constraint effects. • A procedure to account for non-ideal crack profiles. Most crack assessment methods assume an idealized flaw shape such as semi-elliptical, but many real-world flaws have complex shapes.

Bench-KJ: Benchmark on Analytical Calculation of Fracture Mechanics Parameters KI and J for Cracked Piping Components

2012 ◽  
Author(s):  
S. Marie ◽  
C. Faidy
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Analytical Calculation ◽  
Complex Load ◽  
Global Comparison ◽  
Reference Stress ◽  
Calculation Task ◽  
As Stress

For many design and ageing considerations fracture mechanics is needed to evaluate cracked components. The major parameters used are K and J. For that, the different codes (RSE-M appendix 5, RCC-MRx appendix A16, R6 rule, ASME B&PV Code Section XI, API, VERLIFE, Russian Code…) propose compendia of stress intensity factors, and for some of them compendia of limit loads for usual situations, in terms of component geometry, type of defect and loading conditions. The benchmark bench-KJ, proposed in the frame of the OECD/IAGE Group, aims to compare these different estimation schemes by comparison to reference analyses done by Finite Element Method, for representative cases (pipes and elbows, mechanical or/and thermal loadings, different type and size of cracks). The objective is to have a global comparison of the procedures but also of all independent elements as stress intensity factor or reference stress. The benchmark will cover simple cases with basic mechanical loads like pressure and bending up to complex load combinations and complex geometries (cylinders and elbows) including cladding or welds: these cases are classified into 6 tasks. Twenty-eigth partners are involved in this benchmark. This paper gives a global overview of the different tasks of the benchmark and presents the analysis of the results for the first task, devoted on the elastic stress intensity factor calculation (task 1).

scholarly journals The Application of Fracture Mechanics to the Problem of Crevasse Penetration

1976 ◽  
Vol 17 (76) ◽  
pp. 223-228 ◽  
Author(s):  
R. A. Smith
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Stress Intensity Factors ◽  
Close Agreement ◽  
Elastic Stress ◽  
Intensity Factors ◽  
Wide Range ◽  
Sharp Crack

AbstractThe elastic stress intensity factor is a parameter used in fracture mechanics to describe stress conditions in the vicinity of the tip of a sharp crack. By superimposing solutions of stress intensity factors for different loading conditions, equations are derived which model crevasses in ice. Solutions are presented for the theoretical depth of isolated crevasses, free from or partially filled with water. Close agreement exists with a previous calculation by Weertman using a different technique. The effect of crevasse spacing is investigated and it is demonstrated that closer spacing always reduces crevasse depth, but over a wide range of spacing the predicted variation in depth is slight.

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