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.

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

2010 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Phuong H. Hoang ◽  
Bostjan Bezensek
Keyword(s):  
Entire Range ◽  
Estimation Method ◽  
Prediction Method ◽  
Bending Moment ◽  
Combined Loading ◽  
Plastic Collapse ◽  
Finite Element Analyses ◽  
Pure Torsion ◽  
Stainless Steel Pipe ◽  
Service Inspection

When a crack is detected in a pipe during in-service inspection, the failure estimation method given in the codes such as ASME Boiler and Pressure Vessel Code Section XI non-mandatory Appendix C or JSME S NA-1-2008 Appendix E-8 can be applied to assess the integrity of the pipe. In the current editions of these codes, the failure estimation method is provided for bending moment and pressure. Torsion load is assumed to be relatively small and is not considered in the method. In this paper, finite element analyses are conducted for 24-inch stainless steel pipe with a circumferential surface crack subjected to the combined bending and torsion moments, focusing on large and pure torsion moments. Based on the analysis results, a prediction method for plastic collapse under the combined loading conditions of bending and torsion is proposed for the entire range of torsion moments.

Effect of Pressure on Plastic Collapse Under the Combined Bending and Torsion Moments for Circumferentially Surface Flawed Pipes

2010 ◽  
Author(s):  
Yinsheng Li ◽  
Wataru Ida ◽  
Kunio Hasegawa ◽  
Bostjan Bezensek ◽  
Phuong H. Hoang
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Estimation Method ◽  
Bending Moment ◽  
Steel Pipe ◽  
Plastic Collapse ◽  
Finite Element Analyses ◽  
Axial Loads ◽  
Stainless Steel Pipe ◽  
Service Inspection

When a crack is detected in a stainless steel pipe during in-service inspection, the failure estimation method given in the codes such as ASME Boiler and Pressure Vessel Code Section XI or JSME S NA-1-2008 Appendix E-8 can be applied to evaluate the integrity of the pipe. In the current editions of these codes, the failure estimation method is provided considering bending moment and pressure. Torsion load is assumed to be relatively small and not considered in the method. In this paper, finite element analyses are carried out for 24-inch stainless steel pipe with a circumferential surface crack under the multi-axial loads including internal pressure. Based on the analysis results, the failure estimation method for cracked pipe subjected to the combined bending and torsion moments is developed considering the effect of internal pressure.

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.

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.

Experimental Investigation of Failure Estimation Method for Cylinders With a Circumferential Crack Subjected to Combined Tensile and Torsion Loads

2012 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Stainless Steel ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Estimation Method ◽  
Bending Moment ◽  
Failure Behavior ◽  
Axial Loads ◽  
Circumferential Crack ◽  
Torsion Moment

When a crack is detected in a stainless steel pipe during in-service inspections, the failure estimation method given in codes such as the ASME Boiler and Pressure Vessel Code Section XI or JSME Rules on Fitness-for-Service for Nuclear Power Plants can be applied to evaluate the structural integrity of the cracked pipe. In the current codes, the failure estimation method includes the bending moment and axial force due to pressure. The torsion moment is assumed to be relatively small and is not considered. Recently, analytical investigations considering multi-axial loads including torsion were conducted in several previous studies by examining the limit load for pipes with a circumferential crack. A failure estimation method for the combined bending moment, torsion moment and internal pressure was proposed. In this study, the failure behavior of pipes with a circumferential crack subjected to multi-axial loads including the torsion is investigated to provide experimental support for the failure estimation method. Experiments were carried out on small size stainless steel cylinders containing a circumferential surface or through-wall crack, subjected to the combined tensile and torsion loads. Based on the experimental results, the proposed failure estimation method was confirmed to be applicable to cracked pipes subjected to combined tensile and torsion loads.

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 Study on Failure Estimation Method for Circumferentially Cracked Pipes Subjected to Multi-Axial Loads

2015 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Axial Force ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Estimation Method ◽  
Bending Moment ◽  
Estimation Methods ◽  
Failure Behavior ◽  
Axial Loads ◽  
Torsion Moment

When a crack is detected in a piping line during in-service inspections, failure estimation method provided in ASME Boiler and Pressure Vessel Code Section XI or JSME Rules on Fitness-for-Service for Nuclear Power Plants can be applied to evaluate the structural integrity of the cracked pipe. The failure estimation method in the current codes accounts for the bending moment and axial force due to pressure. The torsion moment is not considered. Recently, analytical investigations have been carried out by several authors on the limit load of cracked pipes considering multi-axial loads including torsion and two failure estimation methods for multi-axial loads including torsion moment with different ranges of values have been proposed. In this study, to investigate the failure behavior of cracked pipes subjected to multi-axial loads including the torsion moment and to provide experimental support for the failure estimation methods, failure experiments were performed on 20 mm diameter stainless steel pipes with a circumferential surface crack or a through-wall crack under combined axial force and bending and torsion moments. Based on the experimental results, the proposed failure estimation methods were confirmed to be applicable to cracked pipes subjected to multi-axial loads.

Experimental Investigation on the Failure Estimation Method of Cracked Cylinders Subjected to Multi-Axial Loads

2011 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Stainless Steel ◽  
Nuclear Power ◽  
Power Plants ◽  
Estimation Method ◽  
Bending Moment ◽  
Limit Load ◽  
Analytical Investigation ◽  
Failure Behavior ◽  
Axial Loads ◽  
Torsion Moment

When a crack is detected in a stainless steel pipe during in-service inspections, the failure estimation method given in the codes such as ASME Boiler and Pressure Vessel Code Section XI or JSME Rules on Fitness-for-Service for Nuclear Power Plants can be applied to evaluate the integrity of the cracked pipe. In the current codes, the failure estimation method considers the bending moment and axial force due to pressure. The torsion moment is assumed to be relatively small and is not considered in the method. Recently, an analytical investigation has been carried out by several of our authors on the limit load considering multi-axial loads including torsion, and a failure estimation method for combined bending moment, torsion moment and internal pressure is proposed. In this study, to investigate the failure behavior of cracked pipes subjected to multi-axial loads, including the torsion, and to provide experimental support for the failure estimation method, experiments were carried out on small sized stainless steel cylinders containing a circumferential surface and a through-wall crack, taking into consideration the combined tensile and torsion loads. Based on the experimental results, the proposed failure estimation method is verified for cracked pipes subjected to multi-axial loads.

Experimental Study on Failure Estimation Method for Circumferentially Cracked Pipes Subjected to Multi-Axial Loads

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Axial Force ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Estimation Method ◽  
Bending Moment ◽  
Estimation Methods ◽  
Failure Behavior ◽  
Axial Loads ◽  
Torsion Moment

When a crack is detected in a piping line during in-service inspections, failure estimation method provided in ASME Boiler and Pressure Vessel Code Section XI (ASME Code Section XI) or JSME Rules on Fitness-for-Service for Nuclear Power Plants (JSME FFS Code) can be applied to evaluate the structural integrity of the cracked pipe. The failure estimation method in the current codes accounts for the bending moment and axial force due to pressure. The torsion moment is not considered. Recently, analytical investigation was carried out by the authors on the limit load of cracked pipes considering multi-axial loads including torsion. Two failure estimation methods for multi-axial loads including torsion moment with different ranges were proposed. In this study, to investigate the failure behavior of cracked pipes subjected to multi-axial loads including the torsion moment and to provide experimental support for the failure estimation methods, failure experiments were performed on 20 mm diameter stainless steel pipes with a circumferential surface crack or a through-wall crack under combined axial force, bending moment, and torsion moment. Based on the experimental results, the proposed failure estimation methods were confirmed to be applicable to cracked pipes subjected to multi-axial loads.

Experimental Investigation of Failure Estimation Method for Circumferentially Cracked Pipes Subjected to Combined Bending and Torsion Moments

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Michiya Sakai ◽  
Shinichi Matsuura ◽  
Naoki Miura
Keyword(s):  
Experimental Investigation ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Estimation Method ◽  
Bending Moment ◽  
Limit Load ◽  
Estimation Methods ◽  
Piping System ◽  
Steel Pipes

When a crack is detected in a nuclear piping system during in-service inspections, failure estimation method provided in codes such as ASME Boiler and Pressure Vessel Code Section XI or JSME Rules on Fitness-for-Service for Nuclear Power Plants can be applied to evaluate the structural integrity of the cracked pipe. In the current codes, the failure estimation method for circumferentially cracked pipes is applicable for both bending moment and axial force due to pressure. Torsion moment is not considered. Recently, two failure estimation methods for circumferentially cracked pipes subjected to combined bending and torsion moments were proposed based on analytical investigations on the limit load for cracked pipes. In this study, experimental investigation was conducted to confirm the applicability of the failure estimation method for cracked pipes subjected to bending and torsion moments. Experiments were carried out on 8-in. diameter Schedule 80 stainless steel pipes containing a circumferential surface crack. Based on the experimental results, the proposed failure estimation methods were confirmed to be applicable to cracked pipes subjected to combined bending and torsion moments.

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