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 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 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.

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 Investigation on Failure Estimation Method for Circumferentially Cracked Pipes Subjected to Combined Bending and Torsion Loads

2013 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Michiya Sakai ◽  
Shinichi Matsuura ◽  
Naoki Miura
Keyword(s):  
Experimental Investigation ◽  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Estimation Method ◽  
Bending Moment ◽  
Limit Load ◽  
Piping System ◽  
Torsion Moment

When a crack is detected in a nuclear piping system during in-service inspections, the failure estimation method provided 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 for circumferentially cracked pipes includes bending moment and axial force due to pressure. Torsion moment is not considered. The Working Group on Pipe Flaw Evaluation for the ASME Boiler and Pressure Vessel Code Section XI is developing guidance for combining torsion load within the existing solutions provided in Appendix C for bending and pressure loadings on a pipe. A failure estimation method for circumferentially cracked pipes subjected to general loading conditions including bending moment, internal pressure and torsion moment with general magnitude has been 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 proposed failure estimation method. Experiments were carried out on 8-inch diameter Schedule 80 stainless steel pipes containing a circumferential surface crack. Based on the experimental results, the proposed failure estimation method was confirmed to be applicable to cracked pipes subjected to combined bending and torsion moments.

Failure Experiments on Pipes With Local Wall Thinning Subjected to Multi-Axial Loads

2015 ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Tensile Force ◽  
Estimation Method ◽  
Failure Behavior ◽  
Axial Loads ◽  
Torsion Moment ◽  
Wall Thinning ◽  
Failure Evaluation ◽  
Local Wall Thinning

Piping lines in nuclear power plants may experience multi-axial loads including tensile force, bending and torsion moments during operation. There is a lack of guidance for failure evaluation under the multi-axial loads including torsion moment. ASME B&PV Code Section XI Working Group is currently developing fully plastic failure evaluation procedures for pressurized piping items containing local wall thinning subjected to multi-axial loads. A failure estimation method for locally wall thinned pipes subjected to multi-axial loads including torsion moment has been proposed through numerical analyses. In this study, in order to investigate the failure behavior of the pipes with local wall thinning subjected to multi-axial loads including the torsion, failure experiments were performed on 20 mm diameter carbon steel pipes with a local wall thinning. Based on the experimental results, the proposed failure estimation method is confirmed to be applicable to pipes with local wall thinning.

Failure Experiments on Pipes With Local Wall Thinning Subjected to Multi-Axial Loads

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Tensile Force ◽  
Estimation Method ◽  
Failure Behavior ◽  
Axial Loads ◽  
Torsion Moment ◽  
Wall Thinning ◽  
Failure Evaluation ◽  
Local Wall Thinning

Piping lines in nuclear power plants may experience multi-axial loads including tensile force, bending, and torsion moments during operation. There is a lack of guidance for failure evaluation of locally wall-thinned pipes under the multi-axial loads including torsion moment. The ASME B&PV Code Section XI Working Group is currently developing fully plastic failure evaluation procedures for pressurized piping items containing local wall thinning subjected to multi-axial loads. A failure estimation method for locally wall-thinned pipes subjected to multi-axial loads including torsion moment has been proposed through numerical analyses. In this study, in order to investigate the failure behavior of the pipes with local wall thinning subjected to multi-axial loads including the torsion, failure experiments were performed on 20 mm diameter carbon steel pipes with a local wall thinning. Based on the experimental results, the proposed failure estimation method is confirmed to be applicable to pipes with local wall thinning.

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.

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

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Naoki Miura ◽  
Katsuaki Hoshino
Keyword(s):  
Stainless Steel ◽  
Power Plants ◽  
Structural Integrity ◽  
Tensile Force ◽  
Estimation Method ◽  
Tensile Load ◽  
Bending Moment ◽  
Failure Behavior ◽  
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 tensile force due to pressure. The torsion moment is assumed to be relatively small and is not considered. Recently, analytical investigations considering multiaxial 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 multiaxial 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 load and torsion moment. 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.

Modified J Estimation by GE/EPRI Method for Circumferential Surface Cracked Pipes Under Bending or Combined Bending and Pressure Loads

2011 ◽  
Author(s):  
Jing Zhang ◽  
Chang-Jun Liu ◽  
Fu-Zhen Xuan ◽  
Pei-Ning Li
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Estimation Method ◽  
J Integral ◽  
Element Analysis ◽  
Shape Factors ◽  
Failure Assessment ◽  
Integral Estimation ◽  
J Estimation

In order to assess the structural integrity of the components in nuclear power plants, it is necessary to accurately evaluate the J-integral. EPRI J-integral estimation method has been widely used. However for the pipes with circumferential surface cracks, since the solutions of fully plastic factors H1 were few under the combined pressure and bending loading condition. In such a case, EPRI J-integral might be non-conservative in elastic-plastic transition zone. Considering the problems, detailed finite element analysis (FEA) were conducted in this work, and H1, shape factors F were provided for the pure pressure, pure bending, and combined pressure and bending conditions. The reasons for non-conservatism of EPRI method were discussed, and a modified J estimation method was developed. For validation, failure assessment curves (FACs) were employed to compare the proposed J-integral estimation, EPRI J-integral and FEA method. The results showed that FAC based on the proposed J-integral method agreed well with FEA result, which provided good confidence in the use of this method.

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