bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Anisotropic Mechanical Properties of X70 Spiral Welded Steel Pipes
Authors: Park Dong-Yeob , Liang Jie , Gravel Jean-Philippe 
Published: October 2020

Abstract
Anisotropic tensile and compressive properties of base metals and girth welds of two API X70 spiral welded pipes have been investigated in this study. Spiral welded pipes exhibit different characteristics of anisotropy with respect to pipe axis in comparison with UOE pipes, as the anisotropic property is determined by the thermo-mechanical rolling process of plates and coils produced for pipes. Yield strengths measured from respective tensile and compressive tests are quite comparable at a given material and orientation, although tensile yield strengths are somewhat greater. The results of compressive tests also indicate an anisotropy in the through-thickness direction as well as in the longitudinal direction; high yield strengths are observed at the through-thickness direction or nearby for both base metals and girth welds of the two pipes.
Life Assessment of a Coke Drum by Using the Thermal-Mechanical Fatigue Properties and Laser Scanning Approach
Authors: Han Zhiyuan , Xie Guoshan , Wang Zengchao , Yin Jianzhong , Shi Jin 
Published: October 2020

Abstract
Coke drums are critical equipments in delayed coking plants, which are operated under severe thermal-mechanical conditions by cyclic heating and quenching processes. Cracks are usually developed during service because of severe plastic deformation and low-cycle fatigue. Thus, the assessment of the deformation severity and remaining life is important for safety operating of the coke drums. This study investigated the bulging damage and fatigue life of 6 coke drums after 16 years and 22 years of service in China. A thermal-mechanical fatigue test were first performed to simulate complex loading condition experienced by the coke drum. The thermal-mechanical fatigue life curve of the fabrication material was obtained. Then, a internal laser scanning was employed to measure the deformation and bulges of drum shells. The finite element analysis was developed to calculate the cyclic stress and strain and bulging severity based on the laser mapping and operating conditions. The fatigue life of the coke drum was assessed by the Coffin-Manson-Basquin’s relationship. The life evaluation results of different methods were compared and analyzed. The results showed that a reasonable life of the coke drum can be obtained by using the thermal-mechanical fatigue properties and laser scanning approach.
Tensile and Fatigue Failure of 17-4 PH Martensitic Stainless Steels in Presence of Hydrogen Depending on Frequency and Heat Treatment
Authors: Sezgin Jean-Gabriel , Yamabe Junichiro 
Published: October 2020

Abstract
Slow-strain-rate tensile (SSRT) and fatigue-life tests were carried out on 17-4PH martensitic stainless steel with an ultimate tensile strength (UTS) of ∼ 1 GPa. The specimens were precharged by exposure to hydrogen gas at pressures of 35 MPa or 100 MPa at 270°C for 200 h. The SSRT tests used smooth axisymmetric specimens made of two grades of 17-4PH (H1150 and H900) differing by the UTS due to their thermal history. No degradation of the UTS was observed for both H1150 and H900 grades. However, the relative reduction in area (RRA) was 0.31 for H1150 or 0.11 for H900, translating a difference in their hydrogen sensitivity. Both grades presented different fracture-surface morphologies: a mixture of quasi-cleavage (QC) and intergranular (IG) facets for H1150 and cleavage (C) facets for H900. Circumferentially-notched axisymmetric specimens made of H1150 were used for the fatigue-life tests in the [10−3 Hz;10 Hz] frequency range. Our previous study on low-alloy steels with UTS of around 950 MPa demonstrates that the fatigue life of a circumferentially-notched specimen with a sharp notch can be successfully predicted from the fatigue crack growth (FCG) property following the Paris law. This study used the same specimen geometry and a BCC steel with a similar UTS value; hence, the FCG behavior was investigated from the fatigue-life test of the notched specimen. As a result, the degradation of fatigue lives attributed to the FCG acceleration was observed in presence of hydrogen. A FCG acceleration ratio bounded to 30 was observed in the high-cycle regime, accompanied by QC facets. A FCG acceleration ratio bounded to ∼100 was observed in the low-cycle regime, accompanied by QC and IG facets. A FCG model accounting for the interaction of elementary mechanisms was proposed and succeeded in predicting the FCG acceleration ratio observed on H1150. This model was also successfully applied to a low-alloy steel with a comparable UTS (1002 MPa) tested in gaseous hydrogen.
Estimating Stable Mean Responses for Linear Structural Systems by Using a Limited Number of Acceleration Time Histories
Authors: Nie Jinsuo R. , Xu Jim , Graizer Vladimir , Seber Dogan 
Published: October 2020

Abstract
For seismic analyses of linear structural systems including soil-structure systems, the current practice (e.g., the U.S. Nuclear Regulatory Commission (NRC) Standard Review Plan (SRP) (NUREG-0800 [1], “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition”) and American Society of Civil Engineers (ASCE)/Structural Engineering Institute (SEI) Standard 4-16 [2], “Seismic Analysis of Safety-Related Nuclear Structures”) allows for estimating mean seismic responses by using as few as four or five input time histories. This paper examined whether this practice can achieve a stable mean response by explicitly considering the uncertainty in the Fourier phase spectra of the input time histories and exploring how this uncertainty can affect the coefficient of variation (CV) of the in-structure response spectra (ISRS). ISRS are the response spectra of the seismic response time history at a location in the structure subjected to an input seismic time history. We found that the maximum CVISRS across all frequencies is around 40% purely due to the uncertainty in the Fourier phase spectra for a typical range of design earthquakes for U.S. nuclear power plants. To estimate a mean ISRS within ±10% of the true mean ISRS, our analyses showed that this level of CVISRS may require a minimum of 16 input time histories for a confidence level (CL) of 68% and 61 for a CL of 95% for soil-structure systems of low fundamental frequencies. For stiffer systems (for example, with a fundamental frequency of 5 hertz (Hz)), the maximum CVISRS is about 30%, and thus, the minimum required number of input time histories may be reduced to 9 for a CL of 68% and 35 for a CL of 95%. In summary, the four or five time histories in the current practice may not be sufficient for estimating stable mean responses, especially for soil-structure systems with very low frequencies.
Investigation and Resolution of the Fluid Structure Interaction of High Rate HVGO Pumps
Authors: Kaye Alwyn 
Published: October 2020

Abstract
A suite of High Rate Heavy Vacuum Gas Oil (HVGO) pumps in an operating Upgrader Plant experienced repeated failures; typically, less than 7 weeks. The need for online measuring tools arose that could measure pump and piping system strain changes with dynamic thermal gradients. The challenge was to record the effect on the entirety of pump component alignment and vibration. In current industrial practices no such tools and techniques are directly and comprehensively available for rotary equipment. Strain gauges are not accurate, and cannot provide broader real time strain mapping.
Optical metrology can analyze the mechanical properties and behavior of all kinds of materials in various test scenarios. To date such methods are experimental and principally found in advanced application environments. At the time the method was unknown and especially in such a difficult industrial plant. In such a complex and extreme hot and cold operating service warm-up, cooling, with variations in flow and temperature, can directly and dynamically affect strain measurements.
It was not certain whether optical meorology measurement techniques would be able to identify and correlate dynamic operating scenarios with the source of the pump and pipe hardware issues experienced in these Heavy Vacuum Gas Oil (HVGO) pump systems.
The influence of the casing thickness and stiffness on the resulting vibration characteristics was investigated by using FEA and operational testing and dynamic analysis. Increasing the interface web thickness results in notable reduction in deformation. Comparison of the results of the live testing against the initial design was performed and studied for remedial action. Materials and heat treatment options were also evaluated and reported. The three-dimensional turbulent flow was modelled and analyzed.
The application of those tools for this type of problem are described along with the other rigorous techniques employed. The range of tools included modal and vibration analysis, thermography, rotor and shaft dynamics, baseplate, frame, metallurgical analysis and ultimately compared with FEA, pipe stress modelling and strain analysis.
This paper should be read in conjunction with PVP 2020-21204; Piping & Equipment Dynamics of High Rate HVGO Pumps.
A New Method for Preventing Plastic Collapse of Ellipsoidal Head Under Internal Pressure
Authors: Li Keming , Zheng Jinyang , Zhang Zekun , Gu Chaohua , Xu Ping 
Published: October 2020

Abstract
Ellipsoidal head is a common end closure of pressure vessel. Plastic collapse is a crucial failure mode considered in the design of ellipsoidal head subjected to internal pressure. Internally pressurized ellipsoidal head tends to be hemisphere (geometric strengthening) due to the effect of material hardening before plastic collapse occurs, which enhances load carrying capacity of ellipsoidal head. However, in the current pressure vessel codes such as ASME BPVC.VIII.1 and BPVC.VIII.2, EN 13445-3, and Chinese codes GB/T 150.3 and JB 4732, design methods based on linear elastic or perfectly-plastic theory are used to prevent plastic collapse of ellipsoidal head, leading to conservative design. Therefore, we developed a new method for preventing plastic collapse of ellipsoidal head under internal pressure, considering the effects of material hardening and geometric strengthening. The new method was developed on basis of our previous extensive work on finite element analysis and experiments for plastic collapse of internally pressurized ellipsoidal heads. The new method provides sufficient margin of safety by checking against the experimental bursting results of full-scale ellipsoidal heads with various geometries, various material types and various manufacturing methods. Compared with the design methods in the current pressure vessel codes, the new method shows an advantage of economy. This new method had been approved by China Standardization Committee on Boilers and Pressure Vessels, and at present it has been introduced into the Chinese pressure vessel code.
INCEFA-PLUS: Increasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment
Authors: Mottershead Kevin , Bruchhausen Matthias , Cicero Sergio , Cuvilliez Sam 
Published: October 2020

Abstract
INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 programme. The project concludes in June 2020. 16 organisations from across Europe have combined forces to deliver new experimental data which is being used to develop improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain and stress, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments have been studied experimentally, these being issues of common interest to all participants. The data obtained has been collected and standardised in an online environmental fatigue database, implemented with the assistance of an INCEFA-PLUS led CEN workshop on this aspect. As the end of the project approaches, INCEFA-PLUS is developing and disseminating methods for including the new data into assessment approaches for environmental fatigue degradation.
This paper provides an overall update to project developments since it was last presented at PVP2019 (PVP2019-93276), and provides provisional project conclusions (which will be finalised for presentation at the conference). As well as being a standalone paper, the paper will also serve as an introduction to other papers being submitted covering specific aspects of the project. In particular this paper summarises:
• The results of 3 years of testing (nearly concluded at the time of paper submission)
• A summary of revealed sensitivities to, and inter-dependencies between:
○ Mean strain and stress, surface finish, strain amplitude and hold time.
○ Environment
○ Material
○ Laboratory (including specimen size and form)
• The latest thoughts on how the project results will be used to advance development of improved assessment guidelines.
• Progress developing an International EAF database.
• A summary of dissemination achieved and planned.
• The status of INCEFA-SCALE plans for work after the end of INCEFA-PLUS.
Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 9 — Investigation Regarding Damage Between Furnace and Cage
Authors: Aida Kiyoshi , Minagawa Keisuke , Fujita Satoshi 
Published: October 2020

Abstract
Boilers in coal-fired thermal power plants were often damaged by earthquakes such as the Great East Japan Earthquake in 2011. Since the coal-fired thermal power generation has been one of the main power generation methods after the Great East Japan Earthquake, mitigation of damage of boilers in thermal power plants by earthquakes is the very important subject in order to recover our daily life immediately after strong earthquakes. Meanwhile, a boiler in a coal-fired thermal power plant was damaged by Hokkaido Eastern Iburi Earthquake in 2018, and this damage was one of the causes of Hokkaido’s prefecture-wide blackout. According to a report by an electric power company, a damage occurred between a furnace and a cage of the boiler. In general, lengths, shapes, weights and so on of a furnace are different from a cage, so vibration characteristics and seismic response are different as well. Thus the connecting part between the furnace and the cage is a weak point in the boiler, and the damages often occurred there. Therefore this paper investigates seismic response of a boiler by a numerical analysis using a frame model from the viewpoint of the damage of the furnace and the cage. Various seismic waves were used as input waves in order to investigate the influence of the input wave. A result of a modal analysis was also provided in this paper.
Non-Destructive Examination of Diffusion-Bonded Compact Heat Exchangers
Authors: Selby Greg , Aakre Shaun , Fan Zhaoyan 
Published: October 2020

Abstract
Compact heat exchangers (CHX) fabricated using the diffusion bonding process will be useful in the design and operation of Generation IV nuclear power plants. The NDE challenges posed by diffusion-bonded compact heat exchangers (DBHE) are quite different from those of their more familiar shell-and-tube cousins. The examination scope encompasses three parts: the welds joining the headers to the CHX body; the body’s solid perimeter, serving as the pressure boundary; and the channeled interior. Current investigations are in support of a Section III Code Case including CHX fabrication rules and post-fabrication nondestructive evaluation (NDE) requirements to ensure adequate initial quality. In-service examination methodologies are also considered to inform code developers, regulators, and vendors exploring use of CHX in advanced reactor designs.
The welds joining the headers to the CHX body likely will be full-penetration set-on welds of conventional design. Standard fabrication examinations, namely visual, dye penetrant and hydrostatic examinations will likely suffice. Additional methods should be specified for the purpose of ensuring that the weld stresses have not caused degradation or separation of individual layers within the adjacent diffusion-bonded core. The channeled core of the CHX is geometrically complex and does not allow application of traditional NDE methods from the outside. Radiography permits imaging of small demonstration scale components. Meanwhile, identifying bond failures within larger components may require embedded strain sensors. A theory for employing strain sensors to detect failures within the core is introduced here along with early experimental results. The diffusion-bonded solid perimeter should be examined to ensure that any presence of bonding failures is allowable. Ultrasonic examination results are presented, obtained from test blocks containing simulated bond failures and from high-pressure CHX used during lab studies.
Guidelines for Storage Tank Level 3 Fitness-for-Service Assessments
Authors: Huang John , Subramanian Kannan 
Published: October 2020

Abstract
This paper explores the application of the required loads while performing fitness-for-service (FFS) assessments on an in-service storage tank. Specifically, API 579 – 1, Level 3 FFS assessments involving finite element analyses are studied. In the authors’ experience, due to the absence of specific details about the application of loads within the design codes and post construction standards such as API 579 - 1, the chosen load application is purely at the discretion of the analyst. Often times, choosing one methodology over the other can result in non-conservative assessments. For example, in order to apply wind load pressure distributions on tanks and vessels for plastic collapse and buckling behavior, API 579 – 1 directs the user to ASCE 7 – 16 for wind load calculations. However, previous versions of ASCE 7 did not specify a circumferential pressure distribution for cylindrical structures which can significantly vary around the circumference of a large diameter storage tank. In addition, a few changes in ASCE in the recent edition affect the assessment of in-service tanks for seismic loads. The authors assessed various load cases on tanks of varying diameter to thickness (D/t) ratios and diameter to height ratios. The results show that the choice of loading can have a significant impact on the buckling characteristics of the tanks in-service. This is an attempt to develop some assessment guidelines to support the proposed Tank Assessment Section in a future Edition of API 579 – 1 Standard.
Extrapolation of Creep Rupture Data Using Parametric Numerical Isothermal Datum (P-NID) Method for Inconel 617
Authors: Haque Mohammad Shafinul 
Published: October 2020

Abstract
The development of advanced power plants requires alloys to operate at elevated temperature and pressure for an extended period of time. It is critical to consider creep during the design process to avoid catastrophic failure. Creep rupture data are often not available for desired operating conditions. Accurate extrapolation of creep life is necessary. One of the earliest and most widely used life prediction model is the classic Larson-Miller Parametric (LM) model. Over time numerous time-temperature parametric (TTP) models have been proposed such as Manson-Haferd, Orr-Sherby-Dorn, Manson-Succop, Graham-Walles, Goldhoff-Sherby parametric models. Non-TTP models such as the Wilshire equation is available. The prediction models vary in mathematical form, and number of material constants but shares a common calibration approach. Each model is calibrated against data for every available isotherm. A recently proposed model calibration approach is the parametric numerical isothermal datum (P-NID) method that can be applied to an existing model for improved long-term extrapolation. The P-NID approach is different than the traditional approach as the data are transferred to a datum temperature followed by model calibration against the transferred data at the datum temperature. The calibrated model is then transferred back to the original temperatures.
In this study, the P-NID method is applied to the LM model to perform extrapolation for Inconel 617 alloy. Creep rupture data for five isotherms ranging from 800 to 1000°C and stress levels from 9MPa to 170 MPa are used. A detail step by step procedure is provided for the application of the P-NID method to calibrate the LM model (LM-NID). The extrapolation performance of the classic LM and LM-NID models are compared. Normalized Mean Squared Error (NMSE) is used to analyze prediction accuracy. It is observed that the LM-NID model provides a realistic inflection free prediction compared to the LM model. A 10% data-cull from the lowest stress data is performed to assess the reliability of extrapolation. Based on the comparison a recommendation is provided.
CFD Simulation for Ball Valve Erosion of Natural Gas Pipelines Under Gas-Sand Two-Phase Flow
Authors: Peng Donghua , Dong Shaohua , Zhang Laibin 
Published: October 2020

Abstract
This paper examined the erosion characteristics of the curved core surface of the ball valve when subjected to the two-phase flow of sand-carrying high-pressure gas. The Computational Fluid Dynamics (CFD) method for joint analysis was used to establish the erosion simulation model, the critical factors, such as the ball opening degree, ball diameter affecting the flow field and erosion distribution of the gas-solid two-phase flow were analyzed. The flow field simulation results show that the gas velocity changed violently after entering the ball valve due to the reduction of the cross-sectional area, and the maximum velocity at the turning position increased gradually in conjunction with the decrease in opening degree, while remain unchanged with the increase of ball diameter. Moreover, the particle trajectory show that particles flowing in from the right straight pipe section mainly colliding with three areas including outer wall surface (zone 1), upstream wall surface (zone 2) and the outlet pipe section near the lower wall of the ball valve (zone 3), which were consistent with the location of that particle wall collision happens. The comparative analysis of the maximum erosion rate under different influencing factors shows that decreases with the increase of the ball diameters the opening degree and ball diameter. This research provided theoretical guidance to the erosion analysis of the ball valve core by the two-phase flow of high-pressure sand-carrying gas subjected to the changes in a variety of crucial parameters. This paper also presented a field application value for the design and maintenance of the ball valve in the natural gas pipeline.
The Effect of Cyclic Hardening Model on Deformation Behavior of Cracked Body Under Creep-Fatigue Loading Condition
Authors: Jung Hyun-Woo , Kim Yun-Jae , Takahashi Yukio , Nikbin Kamran , Davies Catrin M. , Ainsworth Robert A. 
Published: October 2020

Abstract
In this study, to determine appropriate cyclic hardening model for simulating creep-fatigue crack growth, sensitivity of hardening model on global/local deformation behavior during creep-fatigue crack growth is studied using finite element (FE) debonding analysis method. Three hardening models derived from tensile stress-strain curve to treat large strain near crack are considered in this study: isotropic hardening model, kinematic hardening model and combined hardening model. Simulation results indicate that cyclic hardening model does not make large difference in global deformation behavior but make difference in local deformation behavior. The effect of hardening model on inelastic strain and stress near crack are discussed in detail.