bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Vertical Load Acting on Whole Roof of Cylindrical Tanks in Nonlinear Sloshing Including Extremely Large Load
Authors: Ikesue Shunichi , Morita Hideyuki , Sago Hiromi , Yokoi Shinobu , Yamamoto Tomohiko 
Published: November 2023

Abstract
When a cylindrical tank is excited by seismic waves, liquid surface motion occurs in the tank. This motion is referred to as sloshing. When a large amplitude sloshing occurs, the liquid surface collides with the roof of the tank, and an impulsive vertical load acts on the roof.
In our previous study, we proposed a predictive evaluation method of the vertical load. The proposed method consists of an impact pressure model, a simplified nonlinear sloshing liquid surface model, and a local liquid surface wave model. The predictive evaluation method almost agreed with test results of the vertical loads acting on load measurement equipment which is attached to a part of the roof of the test model. However, it is necessary to verify the predictive evaluation method for the vertical load acting on the whole roof.
In this study, we proposed the modified predictive evaluation method to deal with large excitation amplitudes and verified this method for the vertical load on the whole roof by the CFD analysis. The modified predictive evaluation method tended to be larger than the CFD analysis under the high and low roof height conditions. On the other hand, the CFD analysis result was extremely larger than the modified predictive evaluation method under the middle roof height condition, despite the small excitation amplitude. In addition, the CFD analysis and the test under the same condition were extremely larger than the modified predictive evaluation method in the maximum load on load measuring equipment.
In this study, we have also discussed this extremely large load, by the CFD analysis. We have found that the previous weak roof collision made the liquid surface a flat shape, and the collision between the flat liquid surface and the roof caused the extremely large load. The result shows that the collision history between the liquid surface and the roof has a significant effect on the vertical load on the roof.
NORSOK U-001 5th Edition 2021 for Subsea Production Systems
Authors: Kirkemo Finn , Muff Anthony David , Stewart Barry , Wormsen Anders 
Published: November 2023

Abstract
NORSOK U-001 provides general requirements for the development, design and manufacture of subsea production systems intended for use on the Norwegian Continental Shelf. NORSOK U-001 5th edition was released in December 2021. Annex B defines requirements for the structural design, materials and fabrication of subsea wellhead, subsea trees, and completion/workover riser systems. An overview and background for the estimation of the static structural capacity as given in this Annex are presented in this paper.
Static structural design analysis methods for combined loading design and pressure design of riser load path components are presented. The link between material requirements and the assumptions made by the finite element based static design analysis methods are emphasized (e.g., ductile failure). Examples of their use for the design of common subsea components such as pipes, wellhead connectors and bolted flanges are given.
The static structural design analysis methods in Annex B have evolved from previous revisions of this standard to address gaps and the missing link between the analysis methods and material properties. The paper ends with a discussion on the limitations of the current edition and outlines future work that could be undertaken to improve and simplify future revisions of Annex B in NORSOK U-001.
Numerical Analysis and Research on Sealing Performance of Flange Connection System in Gas Station
Authors: Li Feng , Zhang Laibin , Dong Shaohua , Wu Wenping 
Published: November 2023

Abstract
Gas stations are vital components in gas gathering and transportation systems. Flanges establish a crucial connection between pipelines, as well as between pipelines and gas station equipment. They primarily rely on the pre-tightening force generated by the bolts to achieve metal sealing. The pre-tightening force is transmitted to the gasket to generate sufficient sealing pressure and avoid fluid medium leaks. The main cause of leakage is a contact gap between the flange and the gasket, which can result in the sealing failure of the flange connection system. The sealing performance of the flange system determines the airtightness of the pipeline system. This paper combined theoretical analysis and simulation to examine the sealing performance of flange system connections in gas stations. Different tightening forces and preloading force sequences were used to numerically analyze the sealing performance of the individual flange components. The compression-rebound characteristics of the flange gaskets and the bolt preload sequences were analyzed, yielding the following results: (1) At different pre-tightening forces, the overall flange stress was uniformly distributed, while the bolt stress was concentrated at the inner side of the stud and the contact position between the bolt and the flange. The stress distribution on the gasket was uniform, with a higher outer than inner stress. (2) The compression rebound curve indicated a certain nonlinearity in the flange gasket at different preloads. Furthermore, the preload caused a flexible graphite metal gasket wound. The degree of elastic or plastic deformation in the gasket increased at a higher preload. Although a higher preload increased the sealing capacity in an appropriate range, excessive preloading induced plastic gasket deformation, causing it to lose its original compression resilience and resulting in seal failure. (3) The flange interaction varied at different loading sequences, while different pre-tightening sequences produced elastic interaction. Therefore, the bolts that were tightened first more significantly affected pre-tightening than those tightened later. Changes were evident in the stress distribution of the gasket, which showed improved sealing performance under sequential and cross-loading.
Effect of High Pressure Hydrogen Gas on Fatigue and Fracture Properties of API X65 LinepIpe Steels
Authors: Nishihara Yoshihiro , Okano Hiroshi 
Published: November 2023

Abstract
Hydrogen is one of the promising energy carriers for achieving a carbon neutral society. The pipeline system is positioned as a major type of infrastructure which will be indispensable for mass transportation of gaseous hydrogen. It is acknowledged that existing natural gas pipelines can be used safely to transport hydrogen blends up to 10 or 20 %. However, it is also known that the mechanical properties of steels are significantly degraded by hydrogen embrittlement, even under small partial pressures of hydrogen. Material degradation is considered in the hydrogen pipeline code ASME B31.12. This code requires evaluation of the fracture and fatigue properties of linepipe materials used under hydrogen, and a critical assessment is conducted so that fracture of the pipeline can be avoided during its service life. In the present study, the hydrogen absorption properties, fracture toughness and fatigue crack growth properties under a 25 MPa hydrogen gas environment were investigated by using 3 kinds of linepipe steels manufactured by different methods. The materials were API X65 linepipe steel, which were manufactured as ERW, LSAW and seamless (SMLS) linepipes. Although all the materials showed a bainitic ferrite generally called, each microstructure had distinctive characteristics attributable to the manufacturing process. While all the linepipe steels showed better fracture toughness and fatigue crack growth rates than the ASME B. 31.12 design curve, their hydrogen absorption properties, fracture toughness in hydrogen gas and fatigue crack growth properties in hydrogen gas differed due to their crystal structures, even though the strength grade of the materials. In the steels used in this study, the fracture toughness and fatigue crack growth characteristics under a hydrogen atmosphere were insensitive to the influence of absorbed hydrogen, and were considered to be influenced by the material factors that determine the fracture toughness and fatigue crack growth characteristics in the atmosphere.
Technical Basis of ASME B31.12 Code Case 218: Use of Enhanced Materials Performance Factors (Hf and Mf) of 1.0
Authors: Xu Kang , Rana Mahendra 
Published: November 2023

Abstract
ASME B31.12 provides piping and pipeline design and construction standards specific for H2 service. Due to the material degradation mechanisms in presence of high-pressure hydrogen, B31.12 imposes a significant reduction in allowable stresses by applying materials performance factors (Hf and Mf) in thickness and design pressure calculations. The reduction factor is as much as 54% for high strength piping and pipeline materials at high hydrogen pressures. The application of the materials performance factors significantly penalizes the use of high strength piping and pipeline materials. In the light of recent developments in understanding hydrogen degradation mechanisms, it is recognized that alternative design and fabrication technologies can be employed to mitigate the risk of hydrogen embrittlement without such penalties. Using fracture mechanics approaches, it has been demonstrated that the materials performance factors can be relaxed by implementing additional requirements in non-destructive examination (NDE) and heat treatment. A B31.12 Code Case has been developed to provide alternative rules to relax the materials performance factors. This Code Case has been approved by ASME B31 Committee and Board on Pressure Technology Codes and Standards, and is ready to be used by code users. This paper reviews the background on Materials Performance Factors in current code, and documents the technical justifications of eliminating these factors.
Simulation Analysis and Experimental Study on Pipeline Circumferential Crack Detection Based on Residual Magnetism Effect
Authors: Wei Haotian , Dong Shaohua , Ma Yundong , Xu Lushuai , Zhao Jiahao , Zhang Hang 
Published: November 2023

Abstract
A method for crack detection on the surface of pipelines that uses residual magnetic detection technology based on the hysteresis effect after magnetizing the pipeline to magnetic saturation has been developed in this study. Support vector regression (SVR) was employed for quantitative assessment. This paper reviewed the magnetization process of the magnetizer, the generation of residual magnetism effect, and the detection of residual magnetic fields. An experimental and theoretical study examined how the crack size affects residual magnetic anomalies. The simulation results indicated that the characteristic values of the residual magnetic anomaly changed in a roughly linear fashion at a more significant crack depth. As the crack width increased, the variations in residual magnetic anomaly characteristic quantities were relatively mild. The input values were denoted by the extracted characteristic amounts. The width and depth parameters of the crack were used as output values. A trained SVR model was employed to estimate the crack size. The crack widths and depths were accurately determined at 62.5% and 85.42%, respectively by combining this detection method, SVR, and the experimental results. This study demonstrated the feasibility of using residual magnetic detection technology, combined with SVR, to detect circumferential cracks in pipelines, which is an essential supplement to internal magnetic flux leakage detection and assessing pipelines.
Near-Neutral pH Stress Corrosion Crack Test Results and Potential Application to Crack Growth Retardation and Hydrogen Sensitivity in Pipeline Steels
Authors: Tiku Sanjay , Lamborn Lyndon , Nelson Greg , Tehinse Olayinka 
Published: November 2023

Abstract
Over a five-year period, a series of fatigue crack growth experiments have been conducted in air and in a bubbling CO2 environment to induce diffusible hydrogen ingress. While the main objective of the hydrogen-charging research targeted characterization of near-neutral stress corrosion crack growth, many of the findings can inform emerging hydrogen transport crack threat management. Summarizing and highlighting these findings and trends could benefit the pipeline industry and accelerate research toward international net zero carbon objectives.
Crack growth retardation in X52 and X65 were found to be readily achieved with an overload cycle, both in air and with hydrogen charging. Subsequent underload cycles were shown to cause resumption of crack advancement: such underload cycles are typical of pipeline operations. Grade X65 pipe steel samples with hydrogen charging were found to be sensitive to underload cycles with significantly higher da/dN growth rates.
Crack retardation models currently available were evaluated using the AFGROW crack growth modeling software to determine and compare model performance to test results. Potential implications of these findings to mainline pipe integrity management are considered in light of crack threat management methods, specifically periodic hydrostatic test methodologies, including emerging hydrogen transport considerations.
Safe Life of Line Pipe in Hydrogen Blended Transport
Authors: Wang Duncan , Hogan James , Lamborn Lyndon 
Published: November 2023

Abstract
A multi-year collaborative project with the Natural Sciences and Engineering Research Council (NSERC) of Canada and the University of Alberta Edmonton (UoA) was launched in October of 2022. The project considers the potential effects of emerging commodity transport demands in support of Canadian Net Zero 2050. The project seeks a deeper understanding of the mechanisms that govern the long-term fatigue behavior of spiral welded pipelines towards informing maintenance scheduling and design. Multi-scale testing and modelling approaches involving materials, fluids, and their interactions are to be pursued. Methodologies developed and knowledge gained have cross-over applicability to seamless and long-seam welded pipe.
Recent full-scale pipeline fatigue testing for various geometric deformations was found to be sufficient to develop preliminary governing S-N curves for pipeline steels in air. A projection of a governing S-N curve family for pipeline steels which are subject to diffusible hydrogen is baselined through correlation with testing under diffusible hydrogen conditions. Full-scale fatigue tests of stress concentrators in carrier pipe steels indicate that a large percentage of the useful fatigue life consists of the crack initiation portion of the life cycle and may be leveraged in making integrity management decisions.
Finally, in this work, the governing S-N curve is resolved into a safe-life plot versus the spectrum severity indicator cycles. This allows operators to project a practical lower bound safe life horizon for line pipe with typical stress concentrators. The study concludes that a multi-year project remains a prudent approach in the event some pipeline operators begin hydrogen or CO2 transport service before the project concludes in 2026.
Influence of Insensitive Strain Region for Strain Rate on Fatigue Life of Stainless Steel in PWR Primary Water Environment
Authors: Kamaya Masayuki 
Published: November 2023

Abstract
It has been shown that the degree of fatigue life reduction due to the pressurized water reactor environment depends on strain rate. It was reported that there was an insensitive strain zone, at which the strain rate had little influence on the fatigue life. The insensitive strain zone existed from the minimum peak strain to a threshold strain, which was determined empirically. This study aimed at determining the insensitive strain zone that corresponds to the crack mouth closure. Fatigue test runs were conducted using cylindrical hollow specimens of Type 316 stainless steel. The cold worked material was also used for the fatigue test. The strain rate was changed at a pre-determined strain, at which the crack mouth was deduced to be opened. It was shown that the fatigue life was almost the same regardless of the strain rate at the insensitive strain zone. Also, the insensitive strain zone could be determined by assuming the crack mouth opened when the stress reached zero in the strain rising phase.
High-Pressure High-Temperature Design Verification and Validation of Well Completion Tools
Authors: Zhou Zhong , Weber Jamie , Yin Shengjun , Apichartthabrut Terapat , Murphy Rob , Abeidoh Abdel Hamid , Zhong Allan 
Published: November 2023

Abstract
While all oil and gas wells operate at pressures and temperatures greater than ambient conditions, wells that are considered high-pressure and high-temperature experience even more challenging operating conditions. These high-pressure, high-temperature (HPHT) wells have pressures greater than 15,000 psi and/or temperatures in excess of 350 °F. These harsh operating conditions result in unique design and safety challenges that are not experienced in more conventional wells. Despite these technical difficulties, the significant resource potential of HPHT wells has attracted development for many years and with advancing technology, the number of HPHT wells is increasing.
Permanent downhole barriers are one of the most critical design challenging tools used in HPHT wellbores. These barriers must reliably hold high differential pressures for decades without leaks, movement, or other failure modes. Experimental and validation testing is expensive and inherently limited in duration of the tests. As a result, HPHT-specific nonlinear numerical simulation is used to complement the physical tests for better reliability, safety, and reduced development time. The HPHT design verification analysis is used to demonstrate compliance with engineering standards, regulatory requirements, and independent third-party review.
This paper presents an analysis procedure for HPHT completion tools through the results from a case study on a permanent bridge plug, a type of downhole pressure isolation tool. The structural integrity is evaluated for multiple loading scenarios per the ASME BPVC Section VIII Division 3 (2017), and the fatigue analysis is conducted based on well-load histograms during the life of the well in accordance with the ASME BPVC Section VIII Division 2 (2017) and API 579-1/ASME FFS-1 (2016). This analysis includes nonlinear finite element analysis, temperature and sour environment effects on materials, and the surface finish effects on structural reliability. The simulations are validated through both component-level and assembly-level testing.
The successful implementation of the HPHT design verification analysis played a significant role in the successful and timely development of the downhole pressure isolation tool.
Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 13 Fragility Analysis Based on Structural Health Monitoring
Authors: Minagawa Keisuke , Aida Kiyoshi , Fujita Satoshi 
Published: November 2023

Abstract
Thermal power plants are one of the critical infrastructure facilities that support modern society. A boiler is a main large structure in a thermal power plant, and it is suspended from its support structure not to restrict thermal expansion, thus it is easy to respond during earthquakes. Therefore, steel dampers are usually installed in boiler structures to absorb vibration energy by plastic deformation of steel. In the meantime, aftershocks of the Great East Japan Earthquake in 2011 have occurred frequently in the Tohoku region even now. For example, in February 2021 and March 2022, large earthquakes of magnitudes 7.3 and 7.4, respectively, occurred in the same epicenter area as the Great East Japan Earthquake. In addition, the long duration and long period ground motions have been focused on after the Great East Japan earthquake. Therefore steel damper has high risk of fatigue failure by earthquakes. Given these backgrounds, it is necessary to improve the seismic resistance of boiler structures, especially for steel dampers.
In this study, we have proposed application of viscoelastic dampers in boiler structures instead of conventional steel dampers. Viscoelastic dampers absorb vibration energy by fluid resistance of a viscoelastic fluid. Component tests of the viscoelastic damper and seismic response analysis using a multi-mass point system and frame model have been conducted in the previous papers. As a result, it was confirmed that the viscoelastic dampers have high vibration control performance and long life. Then, many acceleration sensors have been installed on an actual boiler structure to improve the accuracy of the analytical model used in seismic response analysis, and actual seismic responses have been observed since 2021. In PVP 2023, fragility analysis using seismic response measured in actual seismic events is introduced. Fragility analysis is a powerful tool to quantitatively assess the risk of structural damage. This paper demonstrates the usefulness of structural health monitoring.
Closed Form Formulae of Interaction Factors for Twin Coplanar and Parallel Elliptical Cracks
Authors: Gilles Philippe , Germain Célia , Albrecht David , Desrayaud Cyrille 
Published: November 2023

Abstract
Crack interaction has been a widely studied topic. However exact formulae for crack interaction factors exist only for the case of coplanar through-wall cracks embedded in an infinite elastic medium subjected to normal loading.
Fitness-For-Service (FFS) and regulatory codes provide rules allowing determining whether multiple flaws shall be combined into a single flaw or evaluated separately. However, these rules set thresholds beyond which flaws are replaced by an envelope sometimes over conservative.
This paper presents closed form formulae for interaction factors of two equal elliptical cracks embedded in an isotropic elastic medium subjected to normal loading. The formulae are based on theoretical developments and Finite Element computations achieved by ESI France in a frame of a large program driven by EDF dealing with interaction of volumetric defects. These defects are modelled as cracks in a conservative way.
Based on the interaction formulae between two cracks, an equivalent crack is defined. These cracks are selected considering the strongest interaction. The process is then repeated with the remaining cracks.
Production Low Toughness Case Histories When Manufacturing Low Alloy Steel Pressure Equipment in the Petrochemical Industry
Authors: Dalal Mitul , Hosack Allie , Penso Jorge 
Published: November 2023

Abstract
Low alloy steels containing chromium and molybdenum (CrMo steels) are widely used in pressure equipment in the petrochemical industry. However, if their manufacturing and production welding are not properly controlled, or if they are operating beyond their design conditions, these steels can exhibit brittle behavior at higher than expected temperatures. There are recommendations and requirements in the industry for controlling key parameters during welding. Before they are performed, production weld procedures must be reviewed against the test results from mock-ups to meet certain requirements such as impact toughness, X-bar, and J-factor. However, there is not much industry guidance for assuring the production welding occurs as per the reviewed parameters. This paper discusses three case histories of CrMo alloyed pressure equipment. One of the case histories is for a reactor, and the second case history is for a heat exchanger. The final case history discussed is for piping material. Details of manufacturing, production welding, and testing are discussed in the case histories. For some of the case histories, this includes finding lower impact toughness during production test welding than was expected based on the procedure qualification record. Finally, the paper discusses the importance of additional steps that could be added to the inspection test plan to improve the monitoring of production welding.