Pub Date : 2024-10-11DOI: 10.1016/j.ijpvp.2024.105342
Thamaraiselvi Kumaresan , S. Vishnuvardhan
The safety of a nuclear power plant during incidents, such as a Loss of Coolant Accident (LOCA), heavily relies on conducting a comprehensive structural integrity assessment of both the Reactor Pressure Vessel (RPV) and its components, specifically to withstand Pressurized Thermal Shock (PTS). PTS is characterized by a combination of steep temperature gradient, resulting from the injected emergency coolant during a LOCA, and internal pressure within the RPV. Majority of the reported fracture assessment studies on RPV steel, whether experimental or numerical investigations, have predominantly focused on standard uniaxial specimens at iso-thermal loading conditions. To better simulate the thermal shock scenario in RPVs, the present work aims to assess the impact of a biaxial stress field on both fracture parameters (crack mouth opening displacement and J-integral) and plastic collapse load. This assessment is conducted through experimental and numerical investigations, both with and without prior transient thermal load. Fracture experiments are performed on cruciform bend specimens, featuring two different biaxiality ratios (1:1 and 2:1). Moreover, numerical studies on cruciform specimens are conducted using finite element analysis to validate and corroborate the observations derived from the fracture experiments.
{"title":"Fracture studies on cruciform bend specimens of pressure vessel steel subjected to thermo-mechanical loading","authors":"Thamaraiselvi Kumaresan , S. Vishnuvardhan","doi":"10.1016/j.ijpvp.2024.105342","DOIUrl":"10.1016/j.ijpvp.2024.105342","url":null,"abstract":"<div><div>The safety of a nuclear power plant during incidents, such as a Loss of Coolant Accident (LOCA), heavily relies on conducting a comprehensive structural integrity assessment of both the Reactor Pressure Vessel (RPV) and its components, specifically to withstand Pressurized Thermal Shock (PTS). PTS is characterized by a combination of steep temperature gradient, resulting from the injected emergency coolant during a LOCA, and internal pressure within the RPV. Majority of the reported fracture assessment studies on RPV steel, whether experimental or numerical investigations, have predominantly focused on standard uniaxial specimens at iso-thermal loading conditions. To better simulate the thermal shock scenario in RPVs, the present work aims to assess the impact of a biaxial stress field on both fracture parameters (crack mouth opening displacement and <em>J</em>-integral) and plastic collapse load. This assessment is conducted through experimental and numerical investigations, both with and without prior transient thermal load. Fracture experiments are performed on cruciform bend specimens, featuring two different biaxiality ratios (1:1 and 2:1). Moreover, numerical studies on cruciform specimens are conducted using finite element analysis to validate and corroborate the observations derived from the fracture experiments.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105342"},"PeriodicalIF":3.0,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.ijpvp.2024.105335
Pei Zhang , Fuwei Gu , Zhongliang Cao , Hao Wang , Zhiyang Chen , Hu Xiao , Xinkun Wang , Guoliang Ma
Composite overwrapped pressure vessels (COPVs) are widely used in the field of high-pressure gas storage and transportation because of their light weight and high strength. In engineering, autofrettage is usually used to improve the fatigue life of composite pressure overwrapped vessels with metal liners. However, excessive pressure of autofrettage could cause buckling damage to the metal liner. In order to determine the upper limit of autofrettage (critical buckling pressure) and analyze its influence on the safety factor of COPVs, a theoretical calculation model of the critical buckling pressure about the metal liner was established based on classical laminated plate theory and the confined buckling theory. Then, a COPV with thin-walled welded metal liner was prepared by fiber winding process. In order to monitor and judge the buckling damage mode of the liner, the circumferential strain of the COPV's cylinder was measured by loading and unloading step-by-step. Finally, the influence of materials and dimensions of the metal liner on the pressure ratio (the ratio of the first layer failure pressure to the critical buckling pressure of the COPV's metal liner) was discussed. When the diameter to thickness ratio (R/t) of the metal liner was greater than 35, the pressure ratios of the 6063-T5 aluminum alloy liner and the S30408 stainless steel liner both exceeded 2.25. However, the pressure ratio of 6061-T6 aluminum alloy liner with R/t ≤ 60 was lower than 1.85, which shows that the metal liner with higher yield strength and lower elastic modulus has higher utilization rate of fiber winding layers. Due to the fact that the current design standards only ensure the reliability of COPVs through safety factors and various type testing with their evaluation methods, the proposed theoretical calculation method can reduce the uncertainty of COPVs during the design and testing rounds.
{"title":"Theoretical and experimental research on the critical buckling pressure of the thin-walled metal liner installed in the composite overwrapped pressure vessel","authors":"Pei Zhang , Fuwei Gu , Zhongliang Cao , Hao Wang , Zhiyang Chen , Hu Xiao , Xinkun Wang , Guoliang Ma","doi":"10.1016/j.ijpvp.2024.105335","DOIUrl":"10.1016/j.ijpvp.2024.105335","url":null,"abstract":"<div><div>Composite overwrapped pressure vessels (COPVs) are widely used in the field of high-pressure gas storage and transportation because of their light weight and high strength. In engineering, autofrettage is usually used to improve the fatigue life of composite pressure overwrapped vessels with metal liners. However, excessive pressure of autofrettage could cause buckling damage to the metal liner. In order to determine the upper limit of autofrettage (critical buckling pressure) and analyze its influence on the safety factor of COPVs, a theoretical calculation model of the critical buckling pressure about the metal liner was established based on classical laminated plate theory and the confined buckling theory. Then, a COPV with thin-walled welded metal liner was prepared by fiber winding process. In order to monitor and judge the buckling damage mode of the liner, the circumferential strain of the COPV's cylinder was measured by loading and unloading step-by-step. Finally, the influence of materials and dimensions of the metal liner on the pressure ratio (the ratio of the first layer failure pressure to the critical buckling pressure of the COPV's metal liner) was discussed. When the diameter to thickness ratio (R/t) of the metal liner was greater than 35, the pressure ratios of the 6063-T5 aluminum alloy liner and the S30408 stainless steel liner both exceeded 2.25. However, the pressure ratio of 6061-T6 aluminum alloy liner with R/t ≤ 60 was lower than 1.85, which shows that the metal liner with higher yield strength and lower elastic modulus has higher utilization rate of fiber winding layers. Due to the fact that the current design standards only ensure the reliability of COPVs through safety factors and various type testing with their evaluation methods, the proposed theoretical calculation method can reduce the uncertainty of COPVs during the design and testing rounds.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105335"},"PeriodicalIF":3.0,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.ijpvp.2024.105337
Kai Gao , Yifan Liu , Jingfeng Gong , Kai Ye , Jiahao Gong , Xinglei Dai , Jiawen Du , Pei Li
Steel-aluminum transition joints are commonly produced through explosive welding and friction welding techniques, serving to link aluminum pressure vessels with steel pipes within cold boxes in air separation unit. This study investigates the impact of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of steel-aluminum transition joints created via induction roll welded (IRW), utilizing A283GRC steel and 5052 aluminum alloy as substrates. The findings suggest that the types of intermetallic compounds (IMCs) in IRW joints remain unchanged before and after heat treatment. The thickness of interfacial IMCs increases with higher annealing temperature and longer annealing time, with a faster growth rate at higher annealing temperatures. After PWHT, the grain size near the interface of the joint on the steel side decreased, with the most significant decrease observed when annealed at 300 °C for 2 h. While cracks in the interface zone gradually diminish or disappear with PWHT, excessive heat treatment temperature or duration may result in new transverse cracks. At an annealing temperature of 200 °C, there is limited growth range for IMCs and noticeable repair effect on cracks within the interface region. When annealed at 300 °C and 400 °C, there is a decrease in joint hardness compared to before heat treatment levels, and this decreasing rate accelerates with higher annealing temperature and longer duration. Following annealing at 300 °C for 2 h, the shear strength of the sample reached 70.52 MPa, which is 32 % higher than that before heat treatment. Overall findings suggest that the annealing temperature exerts a more pronounced impact on the mechanical properties of joints in comparison to the annealing duration across the investigated time and temperature ranges. The fracture mode exhibited by the samples before and after heat treatment in IRW is characterized by a mixed fracture mode. However, the predominant fracture mode observed without heat treatment is brittle fracture, whereas after heat treatment, ductile fracture becomes the primary mode of fracture.
{"title":"Effect of post-weld heat treatment on microstructure and mechanical properties of induction roll welded joint for A283GRC steel and 5052 aluminum alloy","authors":"Kai Gao , Yifan Liu , Jingfeng Gong , Kai Ye , Jiahao Gong , Xinglei Dai , Jiawen Du , Pei Li","doi":"10.1016/j.ijpvp.2024.105337","DOIUrl":"10.1016/j.ijpvp.2024.105337","url":null,"abstract":"<div><div>Steel-aluminum transition joints are commonly produced through explosive welding and friction welding techniques, serving to link aluminum pressure vessels with steel pipes within cold boxes in air separation unit. This study investigates the impact of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of steel-aluminum transition joints created via induction roll welded (IRW), utilizing A283GRC steel and 5052 aluminum alloy as substrates. The findings suggest that the types of intermetallic compounds (IMCs) in IRW joints remain unchanged before and after heat treatment. The thickness of interfacial IMCs increases with higher annealing temperature and longer annealing time, with a faster growth rate at higher annealing temperatures. After PWHT, the grain size near the interface of the joint on the steel side decreased, with the most significant decrease observed when annealed at 300 °C for 2 h. While cracks in the interface zone gradually diminish or disappear with PWHT, excessive heat treatment temperature or duration may result in new transverse cracks. At an annealing temperature of 200 °C, there is limited growth range for IMCs and noticeable repair effect on cracks within the interface region. When annealed at 300 °C and 400 °C, there is a decrease in joint hardness compared to before heat treatment levels, and this decreasing rate accelerates with higher annealing temperature and longer duration. Following annealing at 300 °C for 2 h, the shear strength of the sample reached 70.52 MPa, which is 32 % higher than that before heat treatment. Overall findings suggest that the annealing temperature exerts a more pronounced impact on the mechanical properties of joints in comparison to the annealing duration across the investigated time and temperature ranges. The fracture mode exhibited by the samples before and after heat treatment in IRW is characterized by a mixed fracture mode. However, the predominant fracture mode observed without heat treatment is brittle fracture, whereas after heat treatment, ductile fracture becomes the primary mode of fracture.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105337"},"PeriodicalIF":3.0,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.ijpvp.2024.105338
Yingqi Li, Chao Sun
Magnetic flux leakage (MFL) testing technology is widely employed in non-destructive testing of pipelines, and the analysis of leakage signals plays a crucial role in assessing pipelinea safety. This paper introduces a novel approach for MFL testing, which combines finite element simulation with artificial neural networks. First, a finite element model for MFL testing of defects is established, the influence of magnetization states on MFL signals is discussed, and the variation of signal extremum with magnetization intensity is analyzed. Next, suitable MFL signal features are selected to focus on the relationship between defect types, defect sizes, and these features. Finally, a kernel extreme learning machine (KELM) predictive model is developed to classify defect types and predict defect sizes. The results indicate that as magnetization intensity increases, the magnetization process of the pipeline can be divided into a nonlinear growth phase and a linear phase, with MFL signal extremum rapidly increasing and then gradually growing linearly. Different geometric features of defects correspond to distinct distributions of MFL signals, effectively reflecting variations in defect types and sizes. Compared to traditional ELM models, the KELM model achieves higher prediction accuracy and stable performance, with the radial basis kernel function significantly enhancing the generalization and predictive capabilities of the neural network.
{"title":"Research on magnetic flux leakage testing of pipelines by finite element simulation combined with artificial neural network","authors":"Yingqi Li, Chao Sun","doi":"10.1016/j.ijpvp.2024.105338","DOIUrl":"10.1016/j.ijpvp.2024.105338","url":null,"abstract":"<div><div>Magnetic flux leakage (MFL) testing technology is widely employed in non-destructive testing of pipelines, and the analysis of leakage signals plays a crucial role in assessing pipelinea safety. This paper introduces a novel approach for MFL testing, which combines finite element simulation with artificial neural networks. First, a finite element model for MFL testing of defects is established, the influence of magnetization states on MFL signals is discussed, and the variation of signal extremum with magnetization intensity is analyzed. Next, suitable MFL signal features are selected to focus on the relationship between defect types, defect sizes, and these features. Finally, a kernel extreme learning machine (KELM) predictive model is developed to classify defect types and predict defect sizes. The results indicate that as magnetization intensity increases, the magnetization process of the pipeline can be divided into a nonlinear growth phase and a linear phase, with MFL signal extremum rapidly increasing and then gradually growing linearly. Different geometric features of defects correspond to distinct distributions of MFL signals, effectively reflecting variations in defect types and sizes. Compared to traditional ELM models, the KELM model achieves higher prediction accuracy and stable performance, with the radial basis kernel function significantly enhancing the generalization and predictive capabilities of the neural network.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105338"},"PeriodicalIF":3.0,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.ijpvp.2024.105336
Yuhan Wang , Jincheng Hu , Xiaochuan Wang , Shijing Wu
To analyze the dynamic characteristics of whipping behavior induced by the circumferential fracture of high energy pipes, a numerical model of the piping system was presented based on the bidirectional fluid-structure interaction method. The reliability of this model was validated against experimental results. Furthermore, the dynamic characteristics of whipping behavior were studied, as well as the effects of some main parameters. The numerical results suggest that the entire whipping behavior can be divided into four stages: free-whipping stage Ⅰ, free-whipping stage Ⅱ, collision stage and periodic stage. The dynamic response of whipping behavior is different in the four stages and is dominated by a single mode with a frequency of 29.35 Hz under the combined action of the thrust force and U-bolt restraints. The increase of inlet flow rate causes the enhancement of thrust force and thus makes its dynamic response more complicated. The parameter analysis shows that the whipping behavior can be suppressed by choosing the small initial clearance, setting the suitable gap and increasing the straight segment length of U-bolt restraints. The above results are helpful to understand the dynamic characteristics of whipping behavior and provide valuable suggestions for the optimization of the protection measures.
为了分析高能管道周向断裂诱发的鞭打行为的动态特性，基于双向流固耦合方法提出了管道系统的数值模型。实验结果验证了该模型的可靠性。此外，还研究了鞭打行为的动态特征以及一些主要参数的影响。数值结果表明，整个鞭打行为可分为四个阶段：自由鞭打阶段Ⅰ、自由鞭打阶段Ⅱ、碰撞阶段和周期阶段。四个阶段的鞭打行为动态响应不同，在推力和 U 形螺栓约束的共同作用下，以频率为 29.35 Hz 的单一模式为主。入口流速的增加会导致推力的增强，从而使其动态响应变得更加复杂。参数分析表明，通过选择较小的初始间隙、设置合适的间隙和增加 U 型螺栓约束的直线段长度，可抑制鞭打行为。上述结果有助于了解鞭打行为的动态特性，并为优化保护措施提供了宝贵建议。
{"title":"Dynamic analysis of whipping behavior induced by the circumferential fracture of high energy pipes considering fluid-structure interaction effect","authors":"Yuhan Wang , Jincheng Hu , Xiaochuan Wang , Shijing Wu","doi":"10.1016/j.ijpvp.2024.105336","DOIUrl":"10.1016/j.ijpvp.2024.105336","url":null,"abstract":"<div><div>To analyze the dynamic characteristics of whipping behavior induced by the circumferential fracture of high energy pipes, a numerical model of the piping system was presented based on the bidirectional fluid-structure interaction method. The reliability of this model was validated against experimental results. Furthermore, the dynamic characteristics of whipping behavior were studied, as well as the effects of some main parameters. The numerical results suggest that the entire whipping behavior can be divided into four stages: free-whipping stage Ⅰ, free-whipping stage Ⅱ, collision stage and periodic stage. The dynamic response of whipping behavior is different in the four stages and is dominated by a single mode with a frequency of 29.35 Hz under the combined action of the thrust force and U-bolt restraints. The increase of inlet flow rate causes the enhancement of thrust force and thus makes its dynamic response more complicated. The parameter analysis shows that the whipping behavior can be suppressed by choosing the small initial clearance, setting the suitable gap and increasing the straight segment length of U-bolt restraints. The above results are helpful to understand the dynamic characteristics of whipping behavior and provide valuable suggestions for the optimization of the protection measures.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105336"},"PeriodicalIF":3.0,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-29DOI: 10.1016/j.ijpvp.2024.105334
Yongkang Zheng , Zhihao Chen , Hongliang Qian , Ping Wang , Zhenggang Cao
In this study, an optimal shell element modeling approach for tubular joints in ocean engineering was developed utilizing a structural stress analysis. Setting the weld seam thickness of the shell element model to the weld throat size ensured equivalent stiffness between the shell and solid element models. The accuracy of the proposed shell element model was verified by comparing the hot spot stress obtained from the axial loading tests of the three-plane Y-joints carry out by Dalian University of Technology (DUT). The influence of the ratio of chord outer diameter to wall thickness (γ) and the ratio of brace outer diameter to chord outer diameter (β) on stress concentration of K-joints was investigated to evaluate the fatigue performance. The results revealed that for K-joints where the chord is in tension, the β should be as close to 0.5 as possible and should minimize the γ to reduce the stress concentration. For the brace of K-joints under tension, as β and γ increases, the location of fatigue crack initiation transitions from the lower weld toe to the upper weld toe. The β should be avoided around 0.5 and the γ should be as small as possible to minimize the stress concentration.
本研究利用结构应力分析，为海洋工程中的管状接头开发了一种最佳壳体元素建模方法。将壳元素模型的焊缝厚度设定为焊缝喉部尺寸，确保了壳元素模型和实体元素模型之间的等效刚度。通过比较大连理工大学（DUT）三平面 Y 型接头轴向加载试验获得的热点应力，验证了所提出的壳体元素模型的准确性。研究了弦外径与壁厚之比（γ）和支撑外径与弦外径之比（β）对 K 型接头应力集中的影响，以评估其疲劳性能。结果表明，对于弦处于拉伸状态的 K 型关节，β 应尽可能接近 0.5，并应尽量减小 γ 以减少应力集中。对于拉伸状态下的 K 型接头支撑，随着 β 和 γ 的增大，疲劳裂纹的起始位置会从下焊趾过渡到上焊趾。β 应避免在 0.5 左右，γ 应尽可能小，以尽量减少应力集中。
{"title":"A shell equilibrium modeling for stress distribution of offshore tubular joints","authors":"Yongkang Zheng , Zhihao Chen , Hongliang Qian , Ping Wang , Zhenggang Cao","doi":"10.1016/j.ijpvp.2024.105334","DOIUrl":"10.1016/j.ijpvp.2024.105334","url":null,"abstract":"<div><div>In this study, an optimal shell element modeling approach for tubular joints in ocean engineering was developed utilizing a structural stress analysis. Setting the weld seam thickness of the shell element model to the weld throat size ensured equivalent stiffness between the shell and solid element models. The accuracy of the proposed shell element model was verified by comparing the hot spot stress obtained from the axial loading tests of the three-plane Y-joints carry out by Dalian University of Technology (DUT). The influence of the ratio of chord outer diameter to wall thickness (<em>γ</em>) and the ratio of brace outer diameter to chord outer diameter (<em>β</em>) on stress concentration of K-joints was investigated to evaluate the fatigue performance. The results revealed that for K-joints where the chord is in tension, the <em>β</em> should be as close to 0.5 as possible and should minimize the <em>γ</em> to reduce the stress concentration. For the brace of K-joints under tension, as <em>β</em> and <em>γ</em> increases, the location of fatigue crack initiation transitions from the lower weld toe to the upper weld toe. The <em>β</em> should be avoided around 0.5 and the <em>γ</em> should be as small as possible to minimize the stress concentration.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105334"},"PeriodicalIF":3.0,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.ijpvp.2024.105333
Chuan Liu , Hui Xiao , Jialing Yan , Lianju Yan , Long Wang
A thick multi-pass butt-welded ferritic/martensitic steel (P91) joint is prepared and the local region of the weld is repaired with an ENiCrFe-3 nickel-based alloy using the manual metal arc welding method. The repair weld including part of the base metal is then subjected to ultrasonic impact treatment (UIT). A three-cut contour method (CM), including two asymmetric cuts and one symmetric cut, is developed in the present study to obtain the two-dimensional (2D) residual stress distributions at different locations, and the stress release after multiple cuts is considered to get the original stress distribution before cuts. The measurement procedure is introduced in detail. The longitudinal stresses in the repair weld and the initial weld of the P91 steel joint, as well as the transverse stress at the weld center, are finally obtained. The effects of the dissimilar metal repair weld at the local region on the longitudinal and transverse welding residual stresses are investigated. In addition, the applicability of UIT to mitigate the surface stress in nickel-based alloy repair weld is analyzed. The results show that the transverse and longitudinal stresses in the nickel-based alloy repair weld are both tensile stresses, the maximum longitudinal stress is close to the yield strength of the B91 weld metal and occurs in the heat-affected zone of the repair weld located in the initial weld. Repair welding causes the internal transverse compressive stress region to be narrower than in the initial weld. UIT can be used to introduce compressive stress to the surface layer of the nickel-based alloy repair weld.
{"title":"Experimental evaluation of multiple-component residual stress distribution in a dissimilar metal repair joint of ferritic/martensitic steel using the asymmetric-cut and the symmetric-cut contour method","authors":"Chuan Liu , Hui Xiao , Jialing Yan , Lianju Yan , Long Wang","doi":"10.1016/j.ijpvp.2024.105333","DOIUrl":"10.1016/j.ijpvp.2024.105333","url":null,"abstract":"<div><div>A thick multi-pass butt-welded ferritic/martensitic steel (P91) joint is prepared and the local region of the weld is repaired with an ENiCrFe-3 nickel-based alloy using the manual metal arc welding method. The repair weld including part of the base metal is then subjected to ultrasonic impact treatment (UIT). A three-cut contour method (CM), including two asymmetric cuts and one symmetric cut, is developed in the present study to obtain the two-dimensional (2D) residual stress distributions at different locations, and the stress release after multiple cuts is considered to get the original stress distribution before cuts. The measurement procedure is introduced in detail. The longitudinal stresses in the repair weld and the initial weld of the P91 steel joint, as well as the transverse stress at the weld center, are finally obtained. The effects of the dissimilar metal repair weld at the local region on the longitudinal and transverse welding residual stresses are investigated. In addition, the applicability of UIT to mitigate the surface stress in nickel-based alloy repair weld is analyzed. The results show that the transverse and longitudinal stresses in the nickel-based alloy repair weld are both tensile stresses, the maximum longitudinal stress is close to the yield strength of the B91 weld metal and occurs in the heat-affected zone of the repair weld located in the initial weld. Repair welding causes the internal transverse compressive stress region to be narrower than in the initial weld. UIT can be used to introduce compressive stress to the surface layer of the nickel-based alloy repair weld.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105333"},"PeriodicalIF":3.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-25DOI: 10.1016/j.ijpvp.2024.105332
Alexander Kren , Alexander Machikhin , Mikhail Delendik
Residual life of bitumen insulation is an important parameter of urban gas pipelines. Its fast and reliable estimation is necessary for timely health monitoring and coating restoration. In this study, we propose to define lifespan of bitumen insulation in situ from the mechanical characteristics measured during its thermal-oxidative aging. For evaluation of elastic and viscous properties, micro-impact dynamic indentation was applied. We determined the values of activation energy under thermal destruction and the dependence of transient electrical resistance on the critical values of coating's mechanical properties. Obtained experimental data foster real-time estimation of service time of insulation without coating removal.
{"title":"Prediction of the residual lifetime of bitumen coatings on urban gas pipelines from the change in their mechanical characteristics during thermal-oxidative aging","authors":"Alexander Kren , Alexander Machikhin , Mikhail Delendik","doi":"10.1016/j.ijpvp.2024.105332","DOIUrl":"10.1016/j.ijpvp.2024.105332","url":null,"abstract":"<div><div>Residual life of bitumen insulation is an important parameter of urban gas pipelines. Its fast and reliable estimation is necessary for timely health monitoring and coating restoration. In this study, we propose to define lifespan of bitumen insulation <em>in situ</em> from the mechanical characteristics measured during its thermal-oxidative aging. For evaluation of elastic and viscous properties, micro-impact dynamic indentation was applied. We determined the values of activation energy under thermal destruction and the dependence of transient electrical resistance on the critical values of coating's mechanical properties. Obtained experimental data foster real-time estimation of service time of insulation without coating removal.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105332"},"PeriodicalIF":3.0,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface cracks with crack aspect ratio greater than unity have been detected in pipes and cylindrical vessels vulnerable to fatigue and stress corrosion cracking. Accurate solutions of stress intensity factors are prerequisite for predicting the crack growth behaviour of cracked cylinders. In this study, a weight function for the calculation of stress intensity factors for external circumferential surface cracks with high aspect ratio in hollow cylinders is developed. First, three-dimensional finite element models for the surface cracks with aspect ratios 1.0 ≤ a/c ≤ 2.0, ratios of crack depth to thickness 0.1 ≤ a/T ≤ 0.8 and ratios of thickness to inner radius 0.02 ≤ T/Ri ≤ 0.2 are developed and validated. An efficient numerical integration scheme using isotropic elements and the Gauss-Legendre quadrature is suggested for evaluating the integral involving weight function. The unknown weight function coefficients can be then determined by the stress intensity factors obtained from finite element models. Comprehensive comparisons between the results predicted by the derived weight function and finite element analysis are performed for various one-dimensional and two-dimensional stress distributions, indicating a fairly good agreement. The maximum relative errors with respect to finite element solutions are within 8 % for both the surface and deepest points. The present results can complement the database of stress intensity factors and weight function previously developed for external circumferential surface cracks with low aspect ratios 0.2 ≤ a/c ≤ 1.0 in cylinders.
{"title":"Weight function and stress intensity factors for external circumferential surface cracks with high aspect ratio in cylinders","authors":"Kuilin Yuan , Kun Dong , Qitian Fang , Chunbo Zhen","doi":"10.1016/j.ijpvp.2024.105331","DOIUrl":"10.1016/j.ijpvp.2024.105331","url":null,"abstract":"<div><div>Surface cracks with crack aspect ratio greater than unity have been detected in pipes and cylindrical vessels vulnerable to fatigue and stress corrosion cracking. Accurate solutions of stress intensity factors are prerequisite for predicting the crack growth behaviour of cracked cylinders. In this study, a weight function for the calculation of stress intensity factors for external circumferential surface cracks with high aspect ratio in hollow cylinders is developed. First, three-dimensional finite element models for the surface cracks with aspect ratios 1.0 ≤ <em>a</em>/<em>c</em> ≤ 2.0, ratios of crack depth to thickness 0.1 ≤ <em>a</em>/<em>T</em> ≤ 0.8 and ratios of thickness to inner radius 0.02 ≤ <em>T</em>/<em>R</em><sub>i</sub> ≤ 0.2 are developed and validated. An efficient numerical integration scheme using isotropic elements and the Gauss-Legendre quadrature is suggested for evaluating the integral involving weight function. The unknown weight function coefficients can be then determined by the stress intensity factors obtained from finite element models. Comprehensive comparisons between the results predicted by the derived weight function and finite element analysis are performed for various one-dimensional and two-dimensional stress distributions, indicating a fairly good agreement. The maximum relative errors with respect to finite element solutions are within 8 % for both the surface and deepest points. The present results can complement the database of stress intensity factors and weight function previously developed for external circumferential surface cracks with low aspect ratios 0.2 ≤ <em>a</em>/<em>c</em> ≤ 1.0 in cylinders.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105331"},"PeriodicalIF":3.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.ijpvp.2024.105328
Suvan Dev Choudhury, Waris Nawaz Khan, Leijun Li
Boiler water walls experience in-phase thermo-mechanical loading during start-ups and shut-downs, leading to low cycle fatigue (LCF) failure. This study aims at establishing an FEA-based failure prediction method for estimating the fatigue performance and service life of the welded water walls. The developed model is validated for predicting failure in the defect-free uniaxial fatigue specimens. Stress-mechanical strain hysteresis loops and accumulated inelastic strain energy density per cycle parameters are extracted from fatigue tests at 0.4%, 0.6%, and 0.7% strains. A combination of cyclic plasticity and continuous damage mechanics (CDM) theory is utilized to predict fatigue crack initiation sites and estimate the specimen fatigue life. Accumulated damage has been calculated for the life cycle of each specimen. FEA model predicted failure and service life agrees well with the experimental results. The established failure analysis parameters are then transferred from the specimen level to the water wall component level, thereby estimating the service life of defect-free water walls at 750 cycles.
{"title":"Fatigue life predictions for welded boiler water walls","authors":"Suvan Dev Choudhury, Waris Nawaz Khan, Leijun Li","doi":"10.1016/j.ijpvp.2024.105328","DOIUrl":"10.1016/j.ijpvp.2024.105328","url":null,"abstract":"<div><div>Boiler water walls experience in-phase thermo-mechanical loading during start-ups and shut-downs, leading to low cycle fatigue (LCF) failure. This study aims at establishing an FEA-based failure prediction method for estimating the fatigue performance and service life of the welded water walls. The developed model is validated for predicting failure in the defect-free uniaxial fatigue specimens. Stress-mechanical strain hysteresis loops and accumulated inelastic strain energy density per cycle parameters are extracted from fatigue tests at 0.4%, 0.6%, and 0.7% strains. A combination of cyclic plasticity and continuous damage mechanics (CDM) theory is utilized to predict fatigue crack initiation sites and estimate the specimen fatigue life. Accumulated damage has been calculated for the life cycle of each specimen. FEA model predicted failure and service life agrees well with the experimental results. The established failure analysis parameters are then transferred from the specimen level to the water wall component level, thereby estimating the service life of defect-free water walls at 750 cycles.</div></div>","PeriodicalId":54946,"journal":{"name":"International Journal of Pressure Vessels and Piping","volume":"212 ","pages":"Article 105328"},"PeriodicalIF":3.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0308016124002059/pdfft?md5=aa75d5e0aa225cef9cb857fb52d4e6d8&pid=1-s2.0-S0308016124002059-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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