Fully Plastic Failure Stresses and Allowable Crack Sizes for Circumferentially Surface Cracked Pipes Subjected to Tensile Loading

2021 ◽  
Author(s):  
Kunio Hasegawa ◽  
David Dvorak ◽  
Vratislav Mares ◽  
Bohumir Strnadel ◽  
Yinsheng Li
Keyword(s):  
Experimental Data ◽  
Bending Moment ◽  
Limit Load ◽  
Tensile Loading ◽  
Crack Size ◽  
Plastic Failure ◽  
Circumferential Crack ◽  
Asme Code ◽  
American Society ◽  
Better Than

Abstract Fully plastic failure stresses for circumferentially surface cracked pipes subjected to tensile loading can be estimated by means of limit load criteria based on the net-section stress approach. Limit load criteria of the first type (labelled LLC-1) were derived from the balance of uniaxial forces. Limit load criteria of the second type are given in Section XI of the ASME (American Society of Mechanical Engineering) Code, and were derived from the balance of bending moment and axial force. These are labelled LLC-2. Fully plastic failure stresses estimated by using LLC-1 and LLC-2 were compared. The stresses estimated by LLC-1 are always larger than those estimated by LLC-2. From the literature survey of experimental data, failure stresses obtained by both types of LLC were compared with the experimental data. It can be stated that failure stresses calculated by LLC-1 are better than those calculated by LLC-2 for shallow cracks. On the contrary, for deep cracks, LLC-2 predictions of failure stresses are fairly close to the experimental data. Furthermore, allowable circumferential crack sizes obtained by LLC-1 were compared with the sizes given in Section XI of the ASME Code. The allowable crack sizes obtained by LLC-1 are larger than those obtained by LLC-2. It can be stated that the allowable crack size for tensile stress depends on the condition of constraint of the pipe, and the allowable cracks given in Section XI of the ASME Code are conservative.

Flaw Evaluation Procedures and Acceptance Criteria for Nuclear Piping in ASME Code Section XI

2003 ◽  
Author(s):  
Douglas A. Scarth ◽  
Gery M. Wilkowski ◽  
Russell C. Cipolla ◽  
Sushil K. Daftuar ◽  
Koichi K. Kashima
Keyword(s):  
Fracture Mechanics ◽  
Nuclear Power ◽  
Limit Load ◽  
Acceptance Criteria ◽  
Linear Elastic ◽  
Evaluation Procedures ◽  
Piping Systems ◽  
Asme Code ◽  
American Society ◽  
Plant Evaluation

Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code provides rules and requirements for maintaining pressure boundary integrity of components, piping, and equipment during the life of a nuclear power plant. Evaluation procedures and acceptance criteria for the evaluation of flaws in nuclear piping in Section XI of the ASME Code were first published in 1983 and have been under revision for the past several years. This paper provides an overview of the procedures and acceptance criteria for pipe flaw evaluation in Section XI. Both planar and nonplanar flaws are addressed by Section XI. The evaluation procedures and acceptance criteria cover: failure by plastic collapse as characterized by limit load analysis; fracture due to ductile tearing prior to attainment of limit load, as characterized by elastic-plastic fracture mechanics (EPFM) analysis; and brittle fracture as characterized by linear elastic fracture mechanics (LEFM) analysis. A major revision to the evaluation procedures and acceptance criteria was published in the 2002 Addenda to Section XI. Evaluation procedures and acceptance criteria in the 2001 Edition, as well as the revisions in the 2002 Addenda, are described in this paper. Code Cases that address evaluation of wall thinning in piping systems, as well as temporary acceptance of flaws in moderate energy piping systems, are also described.

Failure Bending Moment for Pipes With an Arbitrary-Shaped Circumferential Flaw

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Akira Shibuya ◽  
Nathaniel G. Cofie
Keyword(s):  
Bending Moment ◽  
Limit Load ◽  
Surface Flaw ◽  
Piping System ◽  
Load Carrying Capacity ◽  
Constant Depth ◽  
Load Carrying ◽  
Geometrical Shapes ◽  
Asme Code ◽  
Good Agreement

When a flaw is detected in a stainless steel piping system, an evaluation has to be performed to determine its suitability for continued operation. The failure bending moment of the flawed pipe can be predicted by limit load criterion in accordance with Appendix E-8 in the JSME S NA-1-2008 and/or Appendix C in the ASME Code Section XI. However, in these current codes, the limit load criterion is only calculated for the case of pipes containing a single flaw with constant depth, although the actual flaw depth is variable along the circumferential direction. Particularly, geometrical shapes of stress corrosion cracks are generally complex. The objective of this paper is to propose a method by formula for predicting the load-carrying capacity of pipes containing a circumferential surface flaw with any arbitrary shape. The failure bending moment is obtained by dividing the surface flaw into several subflaw segments. Using this method, good agreement is observed between the numerical solution and the reported experimental results. Several numerical examples are also presented to show the validity of the proposed methodology. Finally, it is demonstrated that three subflaw segments are sufficient to determine the collapse bending moment of a semi-elliptical surface flaw using the proposed methodology.

Prediction Method for Plastic Collapse of Circumferentially Cracked Pipes Subjected to Combined Bending and Torsion Moments

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Phuong H. Hoang ◽  
Bostjan Bezensek
Keyword(s):  
Estimation Method ◽  
Prediction Method ◽  
Bending Moment ◽  
Combined Loading ◽  
Failure Behavior ◽  
Plastic Collapse ◽  
Steel Pipes ◽  
Asme Code ◽  
American Society ◽  
Service Inspection

When a crack is detected in a pipe during in-service inspection, the failure estimation method given in the Codes such as the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI or the Japan Society of Mechanical Engineers (JSME) S NA-1-2008 can be applied to assess the integrity of the pipe. In the current edition of the ASME Code Section XI, the failure estimation method is provided for combined bending moment and pressure loads. The provision of evaluating torsion load is not made in the ASME Code Section XI. In this paper, finite element analyses are conducted for stainless steel pipes with a circumferential surface crack subjected to the combined bending and torsion moments, focusing on the entire range of torsion moments, including pure torsion. The effect of the internal pressure on failure behavior is also investigated. Based on the analysis results, a prediction method for plastic collapse under the combined loading conditions of bending and torsion is proposed for the general magnitude of torsion moments.

Validation of Pipe Flaw Evaluation Procedures in Section XI of the ASME Code Against Pipe Fracture Experiments

2004 ◽  
Author(s):  
Phuong H. Hoang ◽  
Gery M. Wilkowski
Keyword(s):  
Fracture Mechanics ◽  
Nuclear Power ◽  
Limit Load ◽  
Acceptance Criteria ◽  
Linear Elastic ◽  
Evaluation Procedures ◽  
Asme Code ◽  
Elastic Fracture ◽  
American Society ◽  
Plant Evaluation

Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code provides rules and requirements for maintaining pressure boundary integrity of piping during the life of a nuclear power plant. Evaluation procedures and acceptance criteria for the evaluation of flaws in nuclear piping in Section XI of the ASME Code were first published in 1983 and have been under revision for the past several years. The evaluation procedures and acceptance criteria cover: failure by plastic collapse as characterized by limit load analysis; fracture due to ductile tearing prior to attainment of limit load, as characterized by elastic-plastic fracture mechanics (EPFM) analysis; and brittle fracture as characterized by linear elastic fracture mechanics (LEFM) analysis. A major revision to the evaluation procedures and acceptance criteria was published in the 2002 Addenda to Section XI. A brief overview of the pipe flaw evaluation procedures published in the 2002 Addenda are provided in the paper. The evaluation procedures that were published in the 2002 Addenda have been validated against the results of a large number of pipe fracture experiments. The results of this validation exercise are summarized in this paper.

Experimental Limit Load of Forged Piping Branch Junctions and Comparison with Existing Solutions

2005 ◽  
Vol 297-300 ◽  
pp. 1208-1213
Author(s):  
Fu Zhen Xuan ◽  
Pei Ning Li ◽  
Chen Wang
Keyword(s):  
Experimental Data ◽  
Limit Load ◽  
Crack Size ◽  
Load Test ◽  
Test Results ◽  
Experimental Limit ◽  
Structural Dimension ◽  
Corner Cracks

Limit load test results from fourteen forged piping branch junctions are reported. Eight were uncracked. Three had outside, non-through wall cracks running parallel to the run pipe centerline at the flank and the others had crotch corner cracks among the selected specimens. The collapse behaviors such as bulging deformation at the side flanks of junctions with and without crack were depicted. Based on the experimental data, the relationships of limit load with structural dimension and crack size were then summarized and the existing solutions were evaluated in use of the test results.

Prediction of Fully Plastic Failure Stresses for Pipes With Multiple Circumferential Flaws

2007 ◽  
Author(s):  
Kunio Hasegawa ◽  
Koichi Saito ◽  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki
Keyword(s):  
Cross Section ◽  
Evaluation Method ◽  
Limit Load ◽  
Theoretical Method ◽  
Failure Stress ◽  
Combination Rules ◽  
Plastic Failure ◽  
Asme Code ◽  
As Stress ◽  
Single Flaw

Fully plastic failure stress for a single circumferential flaw on a pipe is evaluated by the limit load criteria in accordance with Appendix E-8 in the JSME S NA-1-2004 and Appendix C in the ASME Code Section XI. However, multiple flaws such as stress corrosion cracking are frequently detected in the same circumferential cross section in a pipe. If the distance between adjacent flaws is short, the two flaws are combined as a single flaw in compliance with combination rules. If the two flaws separated by a large distance, it is not required to combine two flaws. However, there is no evaluation method for two flawed pipe in the JSME and ASME Codes. Failure stress for pipes with two circumferential flaws based on net-stress approach had been proposed by one of the authors. The present paper is concerned with the comparison of experimental data and the proposed theoretical method for pipes with circumferentially multiple flaws.

Limit load analysis and safety assessment of an elbow with a circumferential crack under a bending moment

1995 ◽  
Vol 62 (2) ◽  
pp. 109-116 ◽  
Author(s):  
J. Chattopadhyay ◽  
B.K. Dutta ◽  
H.S. Kushwaha ◽  
S.C. Mahajan ◽  
A. Kakodkar
Keyword(s):  
Safety Assessment ◽  
Bending Moment ◽  
Limit Load ◽  
Circumferential Crack ◽  
Load Analysis

Prediction of Failure Bending Moment for a Pipe With an Arbitrary-Shaped Circumferential Flaw

2009 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Akira Shibuya
Keyword(s):  
Bending Moment ◽  
Limit Load ◽  
Surface Flaw ◽  
Experimental Result ◽  
Piping System ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Geometrical Shapes ◽  
Asme Code ◽  
Good Agreement

When a flaw is detected in a stainless steel piping system, failure bending moment can be predicted by limit load criterion in accordance with Appendix E-8 in the JSME S NA-1-2004 and Appendix C in the ASME Code Section XI. However, in these current codes, the limit load criterion is only calculated for the case of a pipe containing a single flaw with constant depth, although the actual flaw depth is variable along the circumferential direction. Particularly, geometrical shapes of stress corrosion cracks are generally complex. The objective of this paper is to propose a method for predicting the load-carrying capacity by formula for a pipe containing a circumferential surface flaw with any arbitrary shape. The failure bending moment is obtained by dividing the surface flaw into several sub-flaw segments. Using this method, good agreement is observed between the numerical solution and the reported experimental result. Several numerical examples are also given to show the validity of this method. Finally, it can be found that the number of the sub-flaw segments is sufficient to be three for the semi-elliptical surface flaw.

Allowable External Flaws and Acceptance Standards for High Toughness Ductile Pipes Subjected to Bending Moment and Internal Pressure

2020 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Valery Lacroix ◽  
Vratislav Mares
Keyword(s):  
Internal Pressure ◽  
Small Diameter ◽  
Bending Moment ◽  
Limit Load ◽  
High Toughness ◽  
Asme Code

Abstract Failure stresses for ductile high toughness pipes are predicted by Limit Load Criteria based on a net section stress concept. Allowable flaws of the Acceptance Standards provided by the Article IWB-3514 in the ASME B&PV Code Section XI were determined by the Limit Load Criteria. The allowable flaws are applicable for ductile high toughness pipes with circumferential internal and external flaws. Authors have developed more precise equations using the Limit Load Criteria, which is called Modified Limit Load Criteria, hereafter. As the results of the Modified Limit Load Criteria, failure stresses for external flawed pipes are always smaller than the failure stresses obtained by the Limit Load Criteria provided by the ASME Code Section XI. It seems that the allowable flaw sizes of the Acceptance Standards provided by the ASME Code Section XI are less conservative for external flaws. The objective of this paper is to demonstrate difference of failure stresses by the Limit Load Criteria and Modified Limit Load Criteria for external flawed pipes. In addition, the allowable flaws of the Acceptance Standards are examined by large and small diameter pipes with external flaws using the Modified Limit Load Criteria.

J-R Curves From Through-Wall Cracked Elbow Subjected to In-Plane Bending Moment

2003 ◽  
Vol 125 (1) ◽  
pp. 36-45 ◽  
Author(s):  
J. Chattopadhyay ◽  
T. V. Pavankumar ◽  
B. K. Dutta ◽  
H. S. Kushwaha
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Bending Moment ◽  
Limit Load ◽  
J Integral ◽  
Finite Element Analyses ◽  
Plane Bending

The evaluation of J-integral from experimental data requires the ηpl and γ functions. However, these functions are available for limited geometry in the literature. In this paper, limit-load-based general expressions of ηpl and γ functions have been derived. These general expressions are then utilized to derive the ηpl and γ functions for through-wall circumferentially/axially cracked elbows under in-plane bending moment which are not available in the literature. The functions are then applied to generate J-R curves from fracture experiments of elbows. Finite element analyses of the tested elbows are also described in the paper.

Sign in / Sign up

Export Citation Format

Share Document