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.

Failure Stresses for Pipes With Multiple Circumferential Flaws

2004 ◽  
Author(s):  
Kunio Hasegawa ◽  
Hideo Kobayashi
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
Combination Rules ◽  
Steel Pipes ◽  
Ductile Materials ◽  
Asme Code ◽  
As Stress ◽  
Simple Equations ◽  
Service Inspection ◽  
Single Flaw

Flaw evaluation for fully-plastic fracture uses the limit load criterion. As stainless steels are high toughness ductile materials, limit load criterion is applicable to stainless steel pipes. When a single circumferential flaw is detected in a stainless steel pipe during in-service inspection, the single flaw is evaluated in accordance with Article EB-4000 in the JSME Code or Appendix C in the ASME Code, Section XI. However, multiple flaws such as stress corrosion cracking are sometimes detected in the same circumferential cress-section in a pipe. If the distance between adjacent flaws is short, the multiple flaws are considered as a single flaw in compliance with combination rules. Failure stress is easily calculated by the equations given by Article EB-4000 or Appendix C. If the two flaws are separated by a large distance, it is not required to combine the two flaws. Each flaw is treated as independent. However, there are no equations for evaluating collapse stress for a pipe containing multiple independent flaws in Article EB-4000 and Appendix C. The present paper focus on a proposal of simple equations for evaluating collapse stresses for pipes containing multiple circumferential part-through wall flaws.

Prediction of Fully Plastic Collapse Stresses for Pipes With Two Circumferential Flaws

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Kunio Hasegawa ◽  
Koichi Saito ◽  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki
Keyword(s):  
Evaluation Method ◽  
Limit Load ◽  
304 Stainless Steel ◽  
Plastic Collapse ◽  
Combination Rules ◽  
Steel Pipes ◽  
Asme Code ◽  
As Stress ◽  
Type 304 ◽  
Type 304 Stainless Steel

Fully plastic collapse stress for a single circumferential flaw on a pipe is evaluated by the limit load criteria in accordance with the JSME Code S NA-1-2004 and 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 separated flaws in a pipe in the JSME and ASME Codes. Plastic collapse stresses for pipes with two symmetrical circumferential flaws based on net-stress approach had been proposed by one of the authors. Bending tests were performed on Type 304 stainless steel pipes with two symmetrical circumferential flaws. Consequently, it was shown that the proposed method can predict well the plastic collapse stresses for pipes with two flaws. In addition, it is also shown that this method is appropriate to use in fitness-for-service procedures, and higher plastic collapse stresses are expected, compared with current prediction methods for pipes with two flaws.

Experimental Estimation of Fully Plastic Collapse Stresses for Pipes With Three Circumferential Flaws

2009 ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki ◽  
Koichi Saito ◽  
Kunio Hasegawa
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
Theoretical Method ◽  
Failure Stress ◽  
Experimental Results ◽  
Past Study ◽  
Bending Tests ◽  
Steel Pipes ◽  
Four Point Bending ◽  
As Stress

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. Hasegawa had proposed failure stress for pipes with two and three circumferential flaws based on net-stress approach. Authors performed four-point bending tests on stainless steel pipes with two symmetrical circumferential flaws in a past study. It was concluded that the experimental results were in good agreement with the theoretical results. In this study, we performed quasi-static four-point bending tests on stainless steel pipes with three symmetrical circumferential flaws. Each experiment resulted in different fracture behavior. We compared the experimental results with the proposed theoretical method.

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.

Estimation of Maximum Load for Pipes With Multiple Circumferential Flaws by Limit Load Analysis

2011 ◽  
Author(s):  
Fuminori Iwamatsu ◽  
Katsumasa Miyazaki ◽  
Koichi Saito ◽  
Tetsuya Hamanaka ◽  
Yoshiaki Takahashi
Keyword(s):  
Limit Load ◽  
Maximum Load ◽  
304 Stainless Steel ◽  
Test Results ◽  
Steel Pipes ◽  
Four Point Bending ◽  
Asme Code ◽  
Load Analysis ◽  
As Stress ◽  
Type 304

Fully plastic failure stress for a single circumferential flaw in a pipe is evaluated by the limit load criteria in accordance with Appendix C in the ASME Code Section XI and Appendix E-8 in the JSME S NA-1-2004. However, multiple flaws such as stress corrosion cracking are frequently detected in the same circumferential cross section in a pipe. Limit load analysis has been validated for pipes with multiple circumferential flaws. Quasi-static four-point bending tests were performed on Type 304 stainless steel pipes with single, double, or triple circumferential flaws. Maximum loads measured in these tests were estimated by limit load analysis for pipes with multiple circumferential flaws. All estimation results using flow stress defined by the JSME S NA-1-2008 are conservative compared to the test results. Estimation results using flow stresses obtained from tests for the pipe with a single flaw quantitatively agree with test results.

Study on Evaluation Method of Corroded Reinforcing Steel

2010 ◽  
Vol 26-28 ◽  
pp. 1184-1189 ◽  
Author(s):  
Ying Zi Zhang ◽  
Ying Fang Fan ◽  
Hong Nan Li ◽  
Xue Nan Wu
Keyword(s):  
Weight Loss ◽  
Energy Loss ◽  
Cross Section ◽  
Strain Energy ◽  
Evaluation Method ◽  
Reinforcing Bars ◽  
Reinforcing Bar ◽  
Important Index ◽  
Steel Bars ◽  
Strain Energy Loss

Corrosion ratio is an important index to study the mechanical deteriorates of the steel bars, which has a significant effect to evaluate the residual bearing capacity of reinforced concrete structures. To investigate the mechanical properties of the corroded steel bars, Strain energy loss as corrosion ratio is firstly proposed. Tensile test are conducted on ribbed and plain steels, which are corroded by acceleration corrosion method. Comparing with the weight loss and cross-section loss to describe the effect of corrosion of reinforcing bar, the strain energy loss of reinforcing bars is calculated by Simpson quadrature. Results from this paper and other researchers’ test suggest that the strain energy loss may be a better parameter than weight loss or section loss which to assess the corroded steel bars.

Allowable Axial Flaw Sizes for Stainless Steel Pipes Derived From Limit Load Criteria and Failure Assessment Diagram Procedure

2003 ◽  
Author(s):  
Kunio Hasegawa ◽  
Katsumasa Miyazaki ◽  
Gery M. Wilkowski ◽  
Douglas A. Scarth
Keyword(s):  
Stainless Steel ◽  
Limit Load ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Steel Pipes ◽  
Failure Assessment Diagram ◽  
Axial Part ◽  
Wide Range ◽  
Failure Assessment ◽  
Asme Code

Piping containing flaws that exceed the Acceptance Standards of Section XI of the ASME Code is evaluated using analytical procedures described in Section XI to determine plant operability for the evaluated time period. Subarticle IWB-3640 of Section XI provides allowable axial and circumferential part-through-wall flaws determined from limit load criteria. ASME Section XI Code Case N-494-3 also provides evaluation procedures based on use of a failure assessment diagram to determine allowable flaw sizes. To understand the allowable flaw sizes determined by the limit load criteria and the failure assessment diagram procedure, anstenitic stainless steel pipes with axial part-through-wall flaws with a wide range of pipe diameters were analyzed. The allowable flaw depth based on limit load from Code Case N-494-3 was determined to be very close to that determined from IWB-3640 of Section XI, when the predicted failure mode is elastic-plastic fracture. It was found that the allowable flaw depths derived from the failure assessment diagram procedure of Code Case N-494-3, are lower, but are not significantly different, from those determined from the limit load criteria of IWB-3640. This is due to the relatively high fracture toughness that was used for the austenitic stainless steel.

Introduction of CASS Pipe Flaw Evaluation of JSME Rules on Fitness for Service

2019 ◽  
Author(s):  
Kiminobu Hojo
Keyword(s):  
Stainless Steel ◽  
Evaluation Method ◽  
Limit Load ◽  
Evaluation Procedure ◽  
Screening Criteria ◽  
Steel Pipes ◽  
Evaluation Procedures ◽  
Degradation Models ◽  
Fracture Tests ◽  
Cast Stainless Steel

Abstract This paper summarizes the revised flaw evaluation procedures for cast austenitic stainless steel (CASS) pipe of the Japan Society of Mechanical Engineers (JSME) rules on fitness for service (FFS) in 2018 addenda. The revision includes the introduction of thermal aging degradation models for stressstrain curve and fracture resistance (J-R) curve, application of a screening criteria for the fracture evaluation procedure of cast stainless steel pipes, and introduction of a new critical stress parameter for the limit load evaluation method of a shallow flaw with a flaw depth to thickness ratio of less than or equal to 0.5. These revisions are based on a large database of specimen tests and several fracture tests of flat plate and large pipe models using thermally aged material, which have already been published.

Numerical Study on Longitudinal Distance Effect on Failure Stress of Non-Aligned Twin Cracked Pipe

2018 ◽  
Author(s):  
Thanh-Long Nguyen ◽  
Myeong-Woo Lee ◽  
Kunio Hasegawa ◽  
Yun-Jae Kim
Keyword(s):  
Fracture Strain ◽  
Numerical Study ◽  
Distance Effect ◽  
Failure Stress ◽  
Axial Distance ◽  
Damage Analysis ◽  
Asme Code ◽  
Bending Stresses ◽  
Strain Model ◽  
Longitudinal Distance

In this study, the effect of longitudinal distance H between non-aligned twin cracks is investigated using finite element damage analysis. The FE damage analysis based on the stress-modified fracture strain model is used to calculate the failure stress of non-aligned twin cracked pipe. Parametric study on the axial distance H between non-aligned twin cracks with various crack depths and lengths were conducted and compared with predictions using the alignment rules and the net-section collapse load approach for single crack provided in ASME Code. It is shown that the trend of the predicted collapse bending stresses for the non-aligned twin cracked pipes using FE damage analysis are different from the ones using the alignment rule.

Theoretic-Strength Concept of a Model Describing the Destruction of the Corner Part of a Slab-Column Structure

2015 ◽  
Vol 240 ◽  
pp. 225-231 ◽  
Author(s):  
Mirosław Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Laboratory Tests ◽  
Concrete Slab ◽  
Load Capacity ◽  
Limit Load ◽  
Traditional Theory ◽  
Load Step ◽  
Reinforced Concrete Slab ◽  
Column Structure

The paper presents a proposed theoretical-strength destruction model of the corner of a slab-column structure at 1:2 scale. The theoretical destruction model was developed on the basis of laboratory tests of a reinforced concrete slab with the dimensions 4000×4000×100 mm. The assumptions of the proposed theoretical model were based on a traditional theory of behaviour of reinforced concrete constructions. The method for calculating the strength of reinforced concrete sections is based on interaction graphs of the load capacity NRd, MRd,x and MRd,y. The calculation method takes into account the influence of changes in the shape of the cross-section of the analysed element on its limit load capacity in every load step.

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