Abstract This technical brief proposes a defect recognition model to recognize four typical defects of phased array ultrasonic testing (PA-UT) images for electrofusion (EF) joints. PA-UT has been proved to be the most feasible way to inspect defects in EF joints of polyethylene pipes. The recognition of defects in PA-UT images relies on the experience of operators, resulting in inconsistent defective detection rate and low recognition speed. The proposed recognition model was composed of an anomaly detection model and a defect detection model. The anomaly detection model recognized anomalies in PA-UT images, meeting the requirement of real-time recognition for practical inspection. The defect detection model classified and located defects in abnormal PA-UT images, achieving high accuracy of defects recognition. By comparing detection models, optimizing parameters and augmenting dataset, the anomaly detection model and defect detection model reached a good combination of accuracy and speed.
{"title":"Convolutional Neural Network Based Defect Recognition Model for Phased Array Ultrasonic Testing Images of Electrofusion Joints","authors":"Yangji Tao, Jianfeng Shi, Weican Guo, Jinyang Zheng","doi":"10.1115/1.4056836","DOIUrl":"https://doi.org/10.1115/1.4056836","url":null,"abstract":"Abstract This technical brief proposes a defect recognition model to recognize four typical defects of phased array ultrasonic testing (PA-UT) images for electrofusion (EF) joints. PA-UT has been proved to be the most feasible way to inspect defects in EF joints of polyethylene pipes. The recognition of defects in PA-UT images relies on the experience of operators, resulting in inconsistent defective detection rate and low recognition speed. The proposed recognition model was composed of an anomaly detection model and a defect detection model. The anomaly detection model recognized anomalies in PA-UT images, meeting the requirement of real-time recognition for practical inspection. The defect detection model classified and located defects in abnormal PA-UT images, achieving high accuracy of defects recognition. By comparing detection models, optimizing parameters and augmenting dataset, the anomaly detection model and defect detection model reached a good combination of accuracy and speed.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136196201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Corrosion is one of the major threats to the safety and structural integrity of oil and gas transmission pipelines. The corrosion threat is usually managed by regular in-line inspection (ILI). The effective area method (RSTRENG) is the most popular corrosion assessment model to convert the measured corrosion size to predicted burst pressure. Given a detailed corrosion measurement profile, the effective area method involves an iterative process to find the minimum burst pressure. As stated in ASME B31G, “for a corroded profile defined by n measurements of depth of corrosion including the end points at nominally full wall thickness, n!/2(n - 2)! iterations are required to examine all possible combinations of local metal loss with respect to surrounding remaining material”, the widely used effective area algorithm has at least an order of n-square time complexity (O(n2)). As n increases, the computation time increases nonlinearly. This paper reviewed the traditional RSTRENG algorithm first, and demonstrated that it is not necessary to always loop through all the combinations and check the corresponding burst pressure one by one. Because some combinations with shallower and shorter corrosion size are certainly not the final critical combination corresponding to the minimum burst pressure. A more efficient algorithm (Faster RSTRENG) is proposed and presented in this paper, which can reduce the algorithm computation time significantly.
{"title":"Faster Rstreng: A More Efficient Effective Area Method Algorithm For Corrosion Assessment","authors":"Jason Yan, D. Lu, Ian Khou, Shenwei Zhang","doi":"10.1115/1.4056932","DOIUrl":"https://doi.org/10.1115/1.4056932","url":null,"abstract":"\u0000 Corrosion is one of the major threats to the safety and structural integrity of oil and gas transmission pipelines. The corrosion threat is usually managed by regular in-line inspection (ILI). The effective area method (RSTRENG) is the most popular corrosion assessment model to convert the measured corrosion size to predicted burst pressure. Given a detailed corrosion measurement profile, the effective area method involves an iterative process to find the minimum burst pressure. As stated in ASME B31G, “for a corroded profile defined by n measurements of depth of corrosion including the end points at nominally full wall thickness, n!/2(n - 2)! iterations are required to examine all possible combinations of local metal loss with respect to surrounding remaining material”, the widely used effective area algorithm has at least an order of n-square time complexity (O(n2)). As n increases, the computation time increases nonlinearly. This paper reviewed the traditional RSTRENG algorithm first, and demonstrated that it is not necessary to always loop through all the combinations and check the corresponding burst pressure one by one. Because some combinations with shallower and shorter corrosion size are certainly not the final critical combination corresponding to the minimum burst pressure. A more efficient algorithm (Faster RSTRENG) is proposed and presented in this paper, which can reduce the algorithm computation time significantly.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46766493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Mostaghimi, Sina Rezvani, Ron Chune, Ron Hugo, Simon S. Park
Pipelines are susceptible to degradation over time due to different types of defects caused by environmental and loading conditions. In-line inspection (ILI) is a preventive examination method widely used to monitor the degradation of pipelines. The passage of an ILI tool through a segment of a pipeline with loose boundary conditions can generate significant dynamic stress within the pipe. When pipelines pass through excavated sites, bridges, water, and bog, or have free-span segments, they are at a greater risk of dynamic stress. This research aims to study the effects of passing an ILI tool through pipelines consisting of straight and curved segments in series. A 3D finite element (FE) model based on the Timoshenko beam theory is developed to model the vibration response of curved pipes during the passage of an ILI tool. Lab-scale experiments are performed to verify the simulation results of the developed FE model. The developed model is further verified through FE analysis performed in ABAQUS™ Implicit. A comparison of the simulation and experimental results shows that the proposed FE model effectively and accurately predicts the dynamic stress and dynamic displacements of multi-segment pipes during the passage of an ILI tool.
{"title":"Dynamic Stress Analysis of Multi-Segment Curved Pipes Subjected To The Passage Of An ILI Tool","authors":"H. Mostaghimi, Sina Rezvani, Ron Chune, Ron Hugo, Simon S. Park","doi":"10.1115/1.4056931","DOIUrl":"https://doi.org/10.1115/1.4056931","url":null,"abstract":"\u0000 Pipelines are susceptible to degradation over time due to different types of defects caused by environmental and loading conditions. In-line inspection (ILI) is a preventive examination method widely used to monitor the degradation of pipelines. The passage of an ILI tool through a segment of a pipeline with loose boundary conditions can generate significant dynamic stress within the pipe. When pipelines pass through excavated sites, bridges, water, and bog, or have free-span segments, they are at a greater risk of dynamic stress. This research aims to study the effects of passing an ILI tool through pipelines consisting of straight and curved segments in series. A 3D finite element (FE) model based on the Timoshenko beam theory is developed to model the vibration response of curved pipes during the passage of an ILI tool. Lab-scale experiments are performed to verify the simulation results of the developed FE model. The developed model is further verified through FE analysis performed in ABAQUS™ Implicit. A comparison of the simulation and experimental results shows that the proposed FE model effectively and accurately predicts the dynamic stress and dynamic displacements of multi-segment pipes during the passage of an ILI tool.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48053517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a minimum toughness assessment method of exempting post-weld heat treatment (PWHT) based on the master curve method is proposed to replace the current method of determining whether to perform PWHT by material thickness. Reference temperature to prevent fracture (T0-required) for structure to exempt from PWHT at minimum design metal temperature (MDMT) was obtained by using the master curve method under presumed stresses and flaw size. A series of exemption curves were generated for the steels used in pressure vessels with yield strength of 300~550MPa, and the method was corrected for low stress conditions. Then the feasibility of this method was verified by an engineering example. A SA-738Gr.B welded joint in the example was taken as the research object, the experiment showed that the weld metal was the worst part of the fracture toughness of the joint. The results of research objects which were exempted from PWHT by the proposed method are consistent with ASME Code Case N-841, which proves that this method is feasible in assessing the exemption from PWHT.
{"title":"Assessing Toughness Levels for Nuclear Containment Vessels Steel to Determine the Need for Pwht Based On the Master Curve Method","authors":"Zehong Chen, Yalin Zhang, Song Huang, H. Hui","doi":"10.1115/1.4056837","DOIUrl":"https://doi.org/10.1115/1.4056837","url":null,"abstract":"\u0000 In this paper, a minimum toughness assessment method of exempting post-weld heat treatment (PWHT) based on the master curve method is proposed to replace the current method of determining whether to perform PWHT by material thickness. Reference temperature to prevent fracture (T0-required) for structure to exempt from PWHT at minimum design metal temperature (MDMT) was obtained by using the master curve method under presumed stresses and flaw size. A series of exemption curves were generated for the steels used in pressure vessels with yield strength of 300~550MPa, and the method was corrected for low stress conditions. Then the feasibility of this method was verified by an engineering example. A SA-738Gr.B welded joint in the example was taken as the research object, the experiment showed that the weld metal was the worst part of the fracture toughness of the joint. The results of research objects which were exempted from PWHT by the proposed method are consistent with ASME Code Case N-841, which proves that this method is feasible in assessing the exemption from PWHT.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43441507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As a key infrastructure in the lifeline system, the safety of the Coal-Fired Thermal Power Plants (CFTPPs) under earthquake loading is not properly considered since a systematic optimization method for seismic design of CFTPPs is scarce. This paper presents a simple iterative method for globally optimizing the dynamic parameters of the typical CFTPPs, which can be considered a special type of tuned mass damping. In this paper, the fixed-point theory is firstly applied to a 2-DOF model of an actual CFTPP as a benchmark. Because the optimized parameters obtained from the fixed-point theory are roughly and cannot be used in practice, an iterative method based on the frequency domain analysis of a 3-DOF model of the CFTPP is then presented and used to obtain more detailed and optimized parameters, where the basic idea is to make extremum values of frequency response curve as small as possible. To show the potential of the proposed method, an illustrative example is introduced, and the results show that the presented method is effective in alleviating the seismic responses of CFTPPs. Compared to the classic fixed-point theory, the presented iterative method can handle multi-DOF models under different conditions but needs no complicated calculations, and this makes it possible to lead to a more efficient and precise seismic design of CFTPPs.
{"title":"An iterative method based on a 3-DOF model for optimal seismic design of coal-fired thermal power plant","authors":"Yuheng Jiang, L. Duan, Jin-cheng Zhao","doi":"10.1115/1.4056838","DOIUrl":"https://doi.org/10.1115/1.4056838","url":null,"abstract":"\u0000 As a key infrastructure in the lifeline system, the safety of the Coal-Fired Thermal Power Plants (CFTPPs) under earthquake loading is not properly considered since a systematic optimization method for seismic design of CFTPPs is scarce. This paper presents a simple iterative method for globally optimizing the dynamic parameters of the typical CFTPPs, which can be considered a special type of tuned mass damping. In this paper, the fixed-point theory is firstly applied to a 2-DOF model of an actual CFTPP as a benchmark. Because the optimized parameters obtained from the fixed-point theory are roughly and cannot be used in practice, an iterative method based on the frequency domain analysis of a 3-DOF model of the CFTPP is then presented and used to obtain more detailed and optimized parameters, where the basic idea is to make extremum values of frequency response curve as small as possible. To show the potential of the proposed method, an illustrative example is introduced, and the results show that the presented method is effective in alleviating the seismic responses of CFTPPs. Compared to the classic fixed-point theory, the presented iterative method can handle multi-DOF models under different conditions but needs no complicated calculations, and this makes it possible to lead to a more efficient and precise seismic design of CFTPPs.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41394263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Paired and Welch's t-tests were used to determine if statistically significant differences exist between the predicted creep rupture life of single- and two-step aged wrought Haynes 282 nickel superalloy. Both tests indicated that there is no difference in the temperature range of 700 - 800 °C. These results provide a quantitative perspective to support the conclusions reached in previous publications that the creep rupture strengths of wrought single- and two-step aged Haynes 282 are very similar or the same. The lack of creep rupture data above 800 °C for two-step aged H282 precluded extending the statistical analysis above that temperature.
{"title":"Statistical Comparison of Creep-Rupture Lifetime Predictions of Single and Two- Step Aged Wrought Haynes 282 Alloy","authors":"V. Cedro, M. Render, Kelechi Chukwunenye","doi":"10.1115/1.4056810","DOIUrl":"https://doi.org/10.1115/1.4056810","url":null,"abstract":"\u0000 The Paired and Welch's t-tests were used to determine if statistically significant differences exist between the predicted creep rupture life of single- and two-step aged wrought Haynes 282 nickel superalloy. Both tests indicated that there is no difference in the temperature range of 700 - 800 °C. These results provide a quantitative perspective to support the conclusions reached in previous publications that the creep rupture strengths of wrought single- and two-step aged Haynes 282 are very similar or the same. The lack of creep rupture data above 800 °C for two-step aged H282 precluded extending the statistical analysis above that temperature.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41381623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A method that estimates cracks that are invisible from the surface based on the surface deformation measured by digital image correlation (DIC) is developing. An inverse problem is set up to estimate such invisible cracks from the surface deformation. Surface deformation, measured by the DIC method, contains noise. Inverse problems have illconditions. The regularization method applied in this study is an extension of the JE-MAP method. The JE-MAP algorithm alternates between Maximum a Posteriori (MAP) method estimation and the Grab-cut (GC) method to avoid ill-conditions. The physical constraints on displacement and the forces at the cracks and the crack perimeters (ligaments) are added to the MAP method. The displacement and load at the cracks and the ligaments have a cross-sparse relationship. The MAP method estimates the displacement or the load at the cracks and the ligaments. The estimated result varies greatly at the boundary between the cracks and the ligaments. This boundary is determined by the GC method based on the estimated result. This study amplified the changes at the boundary between the cracks and the ligaments in the estimated results. The amplified results were input into the GC method to improve the boundary-determination accuracy. The regularization method developed from the JE-MAP method was combined with DIC method to estimate the cracks in invisible locations. The method proposed in this study estimated cracks more accurately than L1norm regularization in inverse problems where the observed data were strain distributions measured by the DIC method.
{"title":"Identification of Crack Shapes by Digital Image Correlation Using JE-MAP Method","authors":"Norihiko Hana, M. Umeda, M. Akiyoshi, K. Amaya","doi":"10.1115/1.4056761","DOIUrl":"https://doi.org/10.1115/1.4056761","url":null,"abstract":"\u0000 A method that estimates cracks that are invisible from the surface based on the surface deformation measured by digital image correlation (DIC) is developing. An inverse problem is set up to estimate such invisible cracks from the surface deformation. Surface deformation, measured by the DIC method, contains noise. Inverse problems have illconditions. The regularization method applied in this study is an extension of the JE-MAP method. The JE-MAP algorithm alternates between Maximum a Posteriori (MAP) method estimation and the Grab-cut (GC) method to avoid ill-conditions. The physical constraints on displacement and the forces at the cracks and the crack perimeters (ligaments) are added to the MAP method. The displacement and load at the cracks and the ligaments have a cross-sparse relationship. The MAP method estimates the displacement or the load at the cracks and the ligaments. The estimated result varies greatly at the boundary between the cracks and the ligaments. This boundary is determined by the GC method based on the estimated result. This study amplified the changes at the boundary between the cracks and the ligaments in the estimated results. The amplified results were input into the GC method to improve the boundary-determination accuracy. The regularization method developed from the JE-MAP method was combined with DIC method to estimate the cracks in invisible locations. The method proposed in this study estimated cracks more accurately than L1norm regularization in inverse problems where the observed data were strain distributions measured by the DIC method.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43176742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fluid end blocks (FEBs) are the most important components of hydraulic fracturing pumps. A potential important application of the hydraulic autofrettage process (HAP) is to strengthen the fatigue-prone FEBs. This creates a favorable compressive residual stress field near to the critical surface locations within the component and serves to increase its pressure-bearing capacity and/or improve lifetime. This requires a fundamental understanding and modeling of the complex mechanics of the HAP in order to accurately predict such residual stresses. The key outstanding modeling issue is the complex material behavior, dominated by the Bauschinger effect and associated with reversed yielding. This effect differs throughout the FEB. It has been modeled for plane axisymmetric cylinders but has not previously been incorporated into FEB analyses. In this paper, a newly developed finite element analysis (FEA)-based user programmable function (UPF), featuring true material constitutive behavior, i.e., replicating an existing Bauschinger-effect characterization (BEC), is adopted to accurately simulate the HAP and quantitatively investigate the stress-strain evolution and residual stress fields throughout the FEB. This simulation is then compared with FEA modeling by a traditional bilinear kinematic hardening material model to indicate the importance of the accuracy of the material constitutive model in determining appropriate residual stresses and strains. An autofrettage pressure of 500MPa generally achieves net compressive hoop stresses at each of four critical crossbore location. Finally, a prospective re-autofrettage sequence is described; approximate modeling suggests an improvement that might permit operation at higher working pressure.
{"title":"Fluid End Blocks: Numerical Analysis of Autofrettage and Reautofrettage Based Upon A True Material Model","authors":"Zhong Hu, A. P. Parker","doi":"10.1115/1.4056605","DOIUrl":"https://doi.org/10.1115/1.4056605","url":null,"abstract":"\u0000 Fluid end blocks (FEBs) are the most important components of hydraulic fracturing pumps. A potential important application of the hydraulic autofrettage process (HAP) is to strengthen the fatigue-prone FEBs. This creates a favorable compressive residual stress field near to the critical surface locations within the component and serves to increase its pressure-bearing capacity and/or improve lifetime. This requires a fundamental understanding and modeling of the complex mechanics of the HAP in order to accurately predict such residual stresses. The key outstanding modeling issue is the complex material behavior, dominated by the Bauschinger effect and associated with reversed yielding. This effect differs throughout the FEB. It has been modeled for plane axisymmetric cylinders but has not previously been incorporated into FEB analyses. In this paper, a newly developed finite element analysis (FEA)-based user programmable function (UPF), featuring true material constitutive behavior, i.e., replicating an existing Bauschinger-effect characterization (BEC), is adopted to accurately simulate the HAP and quantitatively investigate the stress-strain evolution and residual stress fields throughout the FEB. This simulation is then compared with FEA modeling by a traditional bilinear kinematic hardening material model to indicate the importance of the accuracy of the material constitutive model in determining appropriate residual stresses and strains. An autofrettage pressure of 500MPa generally achieves net compressive hoop stresses at each of four critical crossbore location. Finally, a prospective re-autofrettage sequence is described; approximate modeling suggests an improvement that might permit operation at higher working pressure.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44138384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A failure mechanism prevalent with boiler tubes operating in harsh environmental conditions is localized erosion. The consequence of the erosion mechanism is a substantial reduction of the tube thickness, ultimately leading to plastic collapse and consequently rupturing of the tubes. Locating and repairing all the affected tubes within the boiler is time consuming and expensive. It will be worthwhile to rank all the identified flaws so that critical flaws that cannot survive till the next scheduled shutdown are prioritized for repair. Consequently, nonlinear structural analysis was conducted on various boiler tubes that failed by localized erosion. The tubes had a wide range of localized erosion flaws that required a detailed assessment technique. The failure was evaluated numerically using various stress and strain-based failure criteria as well as performing the American Petroleum Institute and the American Society of Mechanical Engineers (API-ASME) fitness-for-service (FFS) assessment on the tubes. A projected time to failure ( P_t) for each tube based on the various criteria used in this study was determined. This enabled the ranking of the flawed tubes based on the priority of their repair. The outcome of this study demonstrates the potential for a tool which will enable industry users to prioritise the replacement or repair of critically flawed tubes and avert replacing tubes that are still safe for future operation.
{"title":"Prediction of the Time to Failure of Boiler Tubes Flawed with Localized Erosion","authors":"I. E. Kalu, H. Inglis, Schalk Kok","doi":"10.1115/1.4056606","DOIUrl":"https://doi.org/10.1115/1.4056606","url":null,"abstract":"\u0000 A failure mechanism prevalent with boiler tubes operating in harsh environmental conditions is localized erosion. The consequence of the erosion mechanism is a substantial reduction of the tube thickness, ultimately leading to plastic collapse and consequently rupturing of the tubes. Locating and repairing all the affected tubes within the boiler is time consuming and expensive. It will be worthwhile to rank all the identified flaws so that critical flaws that cannot survive till the next scheduled shutdown are prioritized for repair. Consequently, nonlinear structural analysis was conducted on various boiler tubes that failed by localized erosion. The tubes had a wide range of localized erosion flaws that required a detailed assessment technique. The failure was evaluated numerically using various stress and strain-based failure criteria as well as performing the American Petroleum Institute and the American Society of Mechanical Engineers (API-ASME) fitness-for-service (FFS) assessment on the tubes. A projected time to failure ( P_t) for each tube based on the various criteria used in this study was determined. This enabled the ranking of the flawed tubes based on the priority of their repair. The outcome of this study demonstrates the potential for a tool which will enable industry users to prioritise the replacement or repair of critically flawed tubes and avert replacing tubes that are still safe for future operation.","PeriodicalId":50080,"journal":{"name":"Journal of Pressure Vessel Technology-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47096252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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