bluuebunny/crossref_metadata_2025_split huggingface dataset:
Master Curve Procedure Accounting for the Combined, Constraint, Ductile Tearing and Loading Rate Effects
Authors: Lindqvist Sebastian , Wallin Kim 
Published: November 2019

Abstract
The probability of brittle fracture is affected, aside from the crack driving force, by changes in constraint, loading rate and crack propagation due to an increase in the sampling volume. In addition, crack propagation, per se, can lead to constraint changes and it also affects the effective strain rate at the crack tip. Especially in the case of leak before break (LBB) where a surface crack transforms instantaneously to a through-wall crack, the increase in local strain rate combined with constraint change and ductile crack extension can be sufficient to cause a transition from ductile fracture to brittle fracture. This, and other similar events, require the development of an advanced Master Curve procedure to account for combined effect of constraint, ductile tearing and loading rate on the brittle fracture probability. A simplified methodology for achieving this is outlined and demonstrated here.
Important Effects in Environmentally Assisted Fatigue (EAF) of Austenitic and Ferritic Steel Components Including Welds and Their Consideration in a Fatigue Assessment Concept
Authors: Rudolph Jürgen , Herbst Matthias , Roth Armin , Swacek Christian , Schopf Tim 
Published: November 2019

Abstract
The fatigue assessment of pressure boundary components is of importance for the aging management regarding safety and reliability in nuclear power plants with light water reactors. For the evaluation of cyclic loading conditions, different country specific design codes and standards are applied to consider various mechanical and thermal loadings as well as geometrical and material effects. Those different influencing factors have also to be taken into account in the fatigue design curves. Current state of the art methods account for life time influencing factors such as temperature, surface finish, stress multi-axiality and loading history by the application of reduction factors for fatigue lives (penalty respectively margin factors) determined from fatigue design curves which are derived from laboratory test data. Other effects, such as environmental effects or hold times, are often considered with high levels of conservatism or are not taken into account at all. On the one hand, this may lead to non-conservative predictions of the materials fatigue behavior, while on the other hand, there are often large discrepancies between calculated fatigue life and practical experience from power plant operation, where the operating experience reveals much higher fatigue lifetimes as their predictions based on laboratory tests and conservative consideration of major influencing factors (plastification by Ke-factors, Environmentally Assisted Fatigue (EAF) by FEN-factors) in the calculation approach.
Therefore, Framatome GmbH, Erlangen, and the Material Testing Institute MPA Stuttgart currently conducting a cooperative research program which aims to improve the understanding of environmental and loading effects as well as of welds on fatigue life time and to improve fatigue lifetime assessment methods in the framework of the well established engineering approach. Based on the results of a previous research project of the same project partners, an experimental program is performed to investigate the effect of loading parameters and hold times on environmentally assisted fatigue (EAF). Experiments on specimens of ferritic and austenitic stainless steels and austenitic stainless steel welds as well as component tests are performed under laboratory and operating conditions to improve fatigue assessment and serve to bridge the gap between specimen behavior and component fatigue in operation.
Emanating from previous and ongoing cooperative research projects, the experimental results will contribute to the proposal of an engineering fatigue assessment concept, allowing more specific differentiation in the influencing factors for component fatigue life prediction. Furthermore, hold time effects are simulated based on further developed material models.
Determination of Inspection Intervals Based on Realistic Load Monitoring and Fracture Mechanics
Authors: Rudolph Jürgen , Bergholz Steffen , Jerinic Dalibor , Rieck Detlef 
Published: November 2019

Abstract
Power plant component condition monitoring with respect of fatigue and creep-fatigue requires information about the real operational loading of the component. Load monitoring systems are available on the market for that purpose. The retrieved load information can be further processed in terms of fatigue assessment based on realistic loading. Moreover, the combination of load monitoring, derivation of stress-time-histories for sentinel locations, cycle counting and fracture mechanics based assessment paves the way of substantiated determination and optimization of non-destructive testing (NDT) inspection intervals. This approach enables a continuous structural health monitoring of critical components even in the sense of online-monitoring capabilities.
This approach provides — in addition to the established fatigue analysis — concrete decisions for the remaining component lifetime and the maximum inspection intervals. This method can also be used if the previous lifetime consumption is unknown. It basically constitutes an advanced damage tolerance approach.
The paper describes a newly developed solution which combines the established Fast Fatigue Evaluation (FFE) approach of Framatome with the THERRI capabilities of TÜV NORD.
An Introduction to China National Standard for On-Board High-Pressure Hydrogen Storage Cylinders
Authors: Huang Gai , Zheng Jinyang , Hua Zhengli , Liao Binbin 
Published: November 2019

Abstract
High-pressure hydrogen storage is a widely used storage method for hydrogen fuel cell vehicles (HFCVs), and most of the new HFCVs use the fully-wrapped carbon fiber reinforced cylinders as the energy storage component. In order to promote the implementation of HFCVs through the creation of performance-based testing requirements for cylinders in China, the national standard named “Fully-wrapped Carbon Fiber Reinforced Cylinders with an Aluminum Liner for the On-board Storage of Compressed Hydrogen as a Fuel for Land Vehicles” (GB/T 35544) has been published in 2018. The GB/T 35544 contains requirements for the material, design, manufacture, marking, and testing of serially produced, refillable cylinders. In this work, the key points of the standard are introduced, including the category of cylinders, the maximum number of fueling cycles, material properties, design qualification tests, etc. In addition, issues that need to be further studied for developing high-pressure hydrogen storage cylinders are also indicated.
Computational Fluid Dynamics Modeling of an Experimental Thermal-Stratification Flow Case Using ABAQUS/CFD
Authors: Franken Daniel , Mohanty Subhasish 
Published: November 2019

Abstract
As the fleet of Pressurized Water Reactors (PWRs) in the United States begin to reach the end of their original lifespan many of them are undergoing assessment to extend their use. In order to investigate the potential for extending the life of the plant, a system level analysis of components needs to be performed in order to ensure that age and degradation of the system will not lead to a potential safety hazard. An area in which this system level investigation is particularly important is in the surge line of the pressurizer. One possible concern is that over the life of the reactor, the surge line pipe will experience thermal stratification many times. Thermal stratification can lead to significant stresses induced on the piping and over time may result in a less than ideal safety standard. Commercially available code Abaqus CFD was used to model the thermal stratification in a pipe. The corresponding experimental results, available in literature were compared. We found there is a good correlation between the experimental and computational results. However, the results discussed in this paper are based on our preliminary effort to study the capability of ABAQUS code for CFD simulation. A detailed parametric study is one of our future work.
Additive Manufactured Pressure Vessel Development: An Update
Authors: Tam Walter , Wlodarczyk Kamil , Hudak Joseph 
Published: November 2019

Abstract
Researchers at Northrop Grumman Innovation Systems (NGIS) have been pursuing the application of additive manufacturing (AM) technology in pressure vessel manufacture for several years. We gained significant insight after the design, analysis, fabrication, and qualification of a 1.8 liter propellant tank with additive manufactured shell in 2017. A Space Propulsion 2018 summary paper titled Additive Manufactured Pressure Vessel Shell included a description of the research and its development progress as of May 2018. Importantly, the authors discussed several items for further examination, including developing a material data base, developing fracture inspection techniques, developing fracture data to facilitate fracture analyses, assessing consistency in material properties, and examining material shedding.
In this summary paper, we review the continuing AM research and development (R&D) activities within NGIS and provide a progress update. The summary paper has three sections. Section 1 contains program background and a description of the evolving NGIS R&D program. In Section 2, we present a progress update. In Section 3, we conclude with a review of our vision towards the implementation of AM technology in space borne pressure vessel manufacture.
Establishment of Industry Standard Flange Sealing Effectiveness Measure (Leakage Rate Based) Methodology
Authors: Lutkiewicz Przemyslaw , Robertson David , Pulvino Michael 
Published: November 2019

Abstract
There are currently no industry accepted methods for calculating sealing effectiveness of flange connections at the research and development phase of a project. As there are many different designs of bolted piping connectors being widely used in the oil and gas industry, operators and regulators could benefit greatly from a more accurate comparison and estimate of expected flange tightness level, based on design calculations only. This paper will propose a new methodology for sealing effectiveness estimation of bolted connections based on leak rate calculations. The methodology will combine practical simplicity and advance theory to get a simple but effective engineering/designing tool to assess the seal tightness. A new proposed method will be based on the contact stress pattern (FEA results), material properties (code specification) and surface finish/roughness (manufacture requirements) as inputs and leak rate estimation as an output. The Representative Surface Element concept will be introduced and presented. In this paper, the general methodology principles will be presented and followed by an engineering example.
Impact of Carbon Macrosegregation on the Mechanical Properties of Low-Alloy Steel Forgings
Authors: Coppard Rémi , Coulon Pascal , Koyama Yoichi , Endo Masaki 
Published: November 2019

Abstract
Macrosegregation in large steel ingots is a known phenomenon: it corresponds to an uneven distribution of alloying elements in the bulk of the as-solidified ingot, over macroscopic scales, caused by the difference in solubility of these elements in the liquid and solid phases. As the ingot solidifies, these elements (mainly carbon, sulfur and phosphorus) concentrate in the liquid phase and are carried to the top of the ingot by convective currents. This process produces large regions of heterogeneity that can negatively impact the mechanical properties of the resulting steel.
Westinghouse is in charge of the manufacture of twelve steam generators (SG) for Electricité de France (EDF), for which the main forged parts are made of 20MND5 low alloy steel. Due to the context and concerns in France, and more broadly in the nuclear industry, on carbon macrosegregation in large scale forgings, Westinghouse led studies with the forgemaster The Japan Steel Works (JSW) in order to assess the influence of carbon content on mechanical properties of such forgings.
The present paper aims at introducing the investigation work carried out by Westinghouse, in partnership with JSW, in order to analyze the effect of increasing carbon on the 20MND5 low-alloy steel tensile and impact toughness properties.
This work was performed through:
- A thorough review of the existing literature;
- The manufacture of forged plates mock-ups, metallurgically representative of the SG channel head, containing various carbon contents (namely 0.18wt.%, 0.21wt.%, 0.26wt.% and 0.29wt.%);
- The testing of above plates to assess the evolution of tensile (tensile strength Rm, 0.2% yield strength Rp0.2 and percentage elongation after fracture) and impact properties (absorbed energy and transition temperature).
New Magnetostrictive Transducers and Applications for SHM of Pipes and Vessels
Authors: Vinogradov Sergey , Fisher Jay L. 
Published: November 2019

Abstract
The use of guided waves for long-range inspection of components is a rapidly growing area of the nondestructive evaluation service industry. Magnetostrictive sensors utilizing ferromagnetic strip material for the transduction effect have proven to be very effective for guided wave testing (GWT) on a variety of components. There is still a demand for enhanced sensor characterization and sensors with specific characteristics. The most challenging area is structural health monitoring (SHM) of components operating at elevated temperatures of at least 200°C.
A new configuration of a sensor for generating and receiving transverse-motion guided waves swaps the biasing and time-varying magnetic field directions. This alternative design is a reversed Wiedemann effect magnetostrictive transducer. These transducers exhibit a number of unique features compared with the more conventional Wiedemann sensor, including: (1) the use of smaller rare earth permanent magnets to achieve large, uniform, and self-sustained bias fields; (2) the use of more efficient electric coil arrangements to induce a stronger time-varying magnetic field for a given coil impedance; (3) the ability to generate both transverse and longitudinal waves; (4) they can be used on pipes ranging from a few millimeters to several meters in diameter.
In this paper, the new transducer design will be described and its performance will be analyzed in application to SHM of pressurized pipe operating at 200°C and automated omnidirectional scan of large storage tank walls.
Bayesian Approach to Estimating Fireball Parameters From Remote Sensing Data
Authors: Armstrong Derek E. 
Published: November 2019

Abstract
Remote sensors in the infrared region can be used to study the progression of fireballs generated from experiments involving high explosives (HE). Developing an improved understanding of HE fireballs can be used to validate and improve computational physics codes that simulate such events. In this paper, Bayesian approaches are studied to estimate time-dependent optimal fireball parameters and their uncertainties using Fourier transform infrared (FTIR) spectroscopy. The optical signal measured by an FTIR sensor provides information on the fireball due to thermal emission, particulate emission/absorption, and HE gas product emission/absorption from the fireball. FTIR sensors have the advantage of being able to capture and measure the radiance in a large part of the infrared spectrum. The parameters to be estimated from the fireball include temperature and size, soot quantity, gas species concentrations (e.g., H2O, CO2, CO), and information on the presence of metals. In general, this inverse optimization problem is difficult due to the estimated quantities being correlated, the low spectral resolution of the FTIR sensor, and the intervening atmosphere absorbing the radiation emitted from the fireball. Bayesian calibration and Bayesian model averaging are applied to address these difficulties and to quantify the uncertainty in the estimated optimal parameter values. The fireball parameter settings are evaluated by the fit of a simplified spectral model to FTIR data. The overall problem will be presented together with a description of the Bayesian approaches. In this paper, the Bayesian approaches are applied to artificially generated FTIR data to illustrate the approach.
Exploring the Uncertainty in the Equation of State for a High Explosive Fit to Heterogeneous Data
Authors: Andrews Stephen A. , Fraser Andrew M. , Jackson Scott I. , Anderson Eric K. 
Published: November 2019

Abstract
The extreme pressures and temperatures of the gas produced by detonating a High Explosive (HE) make it difficult to use experimental measurements to estimate the Equation Of State (EOS), the physics model that relates pressure, temperature, and density of the gas. Instead of measuring pressure directly one measures effects like the acceleration of metals driven by the HE. Typically one fits a few free parameters in a fixed functional form to measurements from a single experiment. The present work uses the optimization tool F_UNCLE to incorporate data from multiple experiments into a single EOS model for the gas produced by detonating the explosive PBX 9501. The model is verified by comparison to an experiment from outside the set of calibration data. The uncertainty in the EOS is also is examined to determine how each calibration experiment constrains the model and how the uncertainty arising from all calibration experiments affects predictions. This work identifies an EOS for HE detonation products and uncertainty about the EOS.
A Numerical Study of Laminar and Intermittently Turbulent Flow Over a Flat Plate Using Pseudo-Compressibility Model
Authors: Srivastava S. , Eastridge J. R. , Taravella B. M. , Akyuzlu K. M. 
Published: November 2019

Abstract
A study was conducted to investigate the characteristics of incompressible unsteady boundary layer flows (laminar and intermittently turbulent), numerically and experimentally. The main objective of the study is to validate and verify (V&V) the accuracy of the proposed pseudo-compressibility model in solving the incompressible Navier-Stokes (NS) equations. This approach will enable one to use a second order accurate (temporally and spatially) implicit finite-difference (FD) technique to solve NS equations (including RANS equations).
Here, the proposed pseudo-compressibility model is used for laminar and intermittent turbulent flow simulations. Flow over a flat plate is chosen as the benchmark case for the validation of the proposed pseudo-compressibility model. An in-house code is developed to solve the boundary layer equations using an Alternating-Direction Explicit (ADE) FD technique. The boundary layer equations are discretized using explicit FD techniques which are second order accurate. The velocity field predicted by this code is compared to the one given by Blasius’ analytical solution. A second in-house code is also developed which adopts the proposed model of pseudo-compressibility to solve the incompressible NS equations. The two dimensional, unsteady conservation of mass and momentum equations are discretized using explicit finite-difference techniques. A standard K-ε closure model is used along with RANS equation to simulate turbulent flows. The primitive variables (velocity and pressure) predicted by this code are compared to the ones predicted by a commercial CFD package (Fluent). Once the method of pseudo-compressibility is validated, it is then implemented into another in-house computer code which employs implicit FD technique and Coupled Modified Strongly Implicit Procedure (CMSIP) to solve for the unknowns of the problem under study.
The predictions based on the pseudo-compressibility model for laminar flow are validated using the results of the experiments in which Particle Image Velocimetry (PIV) technique was employed. The verification; that is, the numerical uncertainty estimation of the pseudo-compressible code was accomplished by using the Grid Convergence Index (GCI) method. The results of the present study indicate that the proposed pseudo-compressibility model is capable of predicting experimentally observed characteristics of the external flows successfully, and deviations between the predicted velocity magnitudes and experimentally measured velocities are within an acceptable range for laminar and intermittently turbulent flows conditions.
ОСОБЛИВОСТІ ЗДОРОВ’Я НАСЕЛЕННЯ СТАРШИХ ВІКОВИХ ГРУП
Authors: Dyachuk M. D. , Gruzieva T. S. , Inshakova G. V. 
Published: November 2019

Мета: встановити сучасні особливості та тенденції здоров’я населення старших вікових груп для виявлення потреб та оптимізації надання медичної допомоги.
Матеріали і методи. При виконанні дослідження використано бібліографічний, медико-статистичний та інформаційно-аналітичний методи. Науковою базою дослідження був багатопрофільний заклад охорони здоров’я. Проаналізовано дані про захворюваність, поширеність хвороб, інвалідність, смертність населення віком 60 років і старше впродовж 2014–2018 рр.
Результати. Виявлено тенденції до збільшення поширеності хвороб серед населення літнього віку на 15,8 % та первинної захворюваності – на 18,2 %. Встановлено головні причини звернень до закладу охорони здоров’я та їх динаміку впродовж чотирирічного періоду. Збільшення звернень населення зумовлено зростанням частоти вперше виявлених захворювань нервової системи (на 204,5 %), кістково-м’язової системи (на 180,2 %), органів дихання (на 78,8 %) та сечостатевої системи (на 36,7 %), що потребує посилення профілактичних заходів та підвищення якості лікування. Комплексно оцінено позитивні та негативні зміни в стані здоров’я пацієнтів літнього віку, включаючи показники інвалідизації та смертності, на основі яких окреслено пріоритетні завдання з удосконалення медичного обслуговування пацієнтів старших вікових груп.
Висновки. Визначені особливості та тенденції стану здоров’я населення старших вікових груп, яких обслуговують в багатопрофільному закладі охорони здоров’я, є підґрунтям для з’ясування проблемних ситуацій, існуючих викликів, встановлення першочергових потреб та їх прогнозування на перспективу, пріоритизації завдань щодо удосконалення медичного обслуговування населення літнього віку.