bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Fatigue Crack Growth at Piping of Austenitic Stainless Steel Under Biaxial Stress
Authors: Harada Shogo , Kitada Takanori , Nakamura Takao 
Published: November 2019

Abstract
The fatigue degradation in Nuclear Power Plants (NPPs) is evaluated by a design fatigue curve that is published in ASME code which is based on the results of uniaxial fatigue test data. On the other hand, stress that occurs at actual piping elements, such as elbows, is not uniaxial stress but biaxial stress, with different stress ratios. Stress ratio is defined as the ratio of stress range in one axis to that in the other axis. In this study, a pressurized disc fatigue test machine is developed in order to conduct biaxial fatigue test under different stress ratio more easily and low-cost. A newly designed test specimen is adopted to generate biaxial stress under different stress ratios near the center of the specimen. This test machine can generate a specific biaxial stress with different stress ratios at specimen by adjusting air pressure and shape of the specimen.
Novel Modeling of Mean Stress Effect on the High-Cycle Fatigue Performance of Preloaded Threaded Fasteners
Authors: Nassar Sayed A. , Li Tianwu 
Published: November 2019

Abstract
An experimentally validated model is proposed for the effect of fastener mean stress on its high cycle fatigue (HCF) performance. The model is also used for comparing fatigue performance of ultra-high strength (UHS) fasteners Class 14.8, 15.8 and 16.8 with that of commercially available (CA) Class 10.9 and 12.9 fasteners. Respective mean stress-adjusted S-N curves are constructed using experimental data following applicable ASTM standards. Proposed model results are compared with other existing models that account for the effect of mean stress such as Goodman, Gerber, Morrow, Soderberg, and Elliptic (ASME) models. Detailed discussion of the results, failure mode, and conclusions are provided.
Light Weight Design of Multi-Layered Steel Vessels for High-Pressure Hydrogen Storage
Authors: Ye Sheng , Zheng Jinyang , Yu Ting , Gu Chaohua , Hua Zhengli 
Published: November 2019

Abstract
Large scale storage of hydrogen is one of the key factors in hydrogen energy development. High-pressure hydrogen storage technology is widely used in hydrogen storage. It has advantages of easy operating, quick charge and discharge, simple equipment structure and low cost. The multi-layered steel vessel (MLSV) was developed for stationary hydrogen storage, which was flexible in design, safe in operation and convenient in fabrication. MLSV has been used in several hydrogen refueling stations in China. With the construction of hydrogen refueling stations accelerated, the vessel was required to be larger, lighter and cheaper. First, the basic structure of the MLSV was presented. Second, two light-weight methods were proposed and compared, including reducing the safety factor and increasing the strength of the steel band. Finally, the stress in the cylindrical shell of the MLSV using light-weight design were compared with the previous one. In addition, a MLSV using the light-weight method of reducing safety factor has been designed and fabricated, which can store 211 kg gaseous hydrogen at 50MPa.
Welding Process Development for Spent Nuclear Fuel Canister Repair
Authors: Tang Wei , Chatzidakis Stylianos , Miller Roger , Chen Jian , Kyle Doug , Scaglione John , Schrad Caleb 
Published: November 2019

Abstract
The potential for stress corrosion cracking (SCC) of welded stainless-steel interim storage containers for spent nuclear fuel (SNF) has been identified as a high priority data gap. This paper presents a fusion welding process that was developed for SNF canister repair. Submerged arc welding (SAW) was developed to weld 12.7 mm (0.5 in.) thick 304L stainless steel plates to simulate the initial welds on SNF canisters. The SAW procedure was qualified following ASME Boiler and Pressure Vessel Code requirements. During SAW, the welding temperature was recorded at various locations by using thermocouples. After SAW, weld microstructures were characterized, joint mechanical properties were tested, and the maximum tensile residual stress direction was identified. After SAW procedure qualification, artificial cracks were excavated perpendicular to the maximum tensile residual stress direction in the SAW heat affected zone. Machine cold-wire gas tungsten arc welding (CW-GTAW) was developed and used for repair welding at cracked locations.
Implementation and Validation of a Fully Mechanistic Fatigue Modeling Approach in a High Performance Computing Framework
Authors: Barua Bipul , Mohanty Subhasish , Majumdar Saurindranath , Natesan Krishnamurti 
Published: November 2019

Abstract
Current approaches of fatigue evaluation of nuclear reactor components or other safety critical structural systems use S∼N curve based empirical relations which may have large uncertainty. This uncertainty may be reduced by using a more mechanistic approach. In the proposed mechanistic approach, material models are developed based on the evolution of material behavior under uniaxial fatigue experiments and implement those models into 3D finite element (FE) calculations for fatigue evaluation under multiaxial loading. However, this approach requires simulating structures under thousands of fatigue cycles which necessitates the use of high performance computing (HPC) to determine fatigue life of a large component/system within reasonable time frame. Speeding up the FE simulation of large systems requires the use of a higher number of cores, which is extremely costly, particularly when a commercial FE code is used. Also, commercial software is not necessarily optimized for use in an HPC environment. In this work, an open source parallel computing solver along with a multi-core cluster is used to scale up the number of cores. The HPC-based mechanistic fatigue modeling framework is validated through evaluating fatigue life of a pressurized water reactor surge line pipe under idealistic loading cycles and comparing the simulation results with observations from uniaxial fatigue experiment of 316 stainless steel specimen.
Time-Series Fatigue Damage States Forecasting and Probabilistic Environmental Fatigue Life Prediction Using Markov-Chain-Monte-Carlo Techniques
Authors: Park Jae Phil , Mohanty Subhasish , Bahn Chi Bum 
Published: November 2019

Abstract
In general, probabilistic fatigue life estimation were performed using Weibull analysis and end-of-life fatigue data. This is basically using traditional strain/stress ∼ life (S∼N) data. Although it is always better to estimate the reliability of a component based on probabilistic evaluation of end-of-life data, it may not be always possible to conduct hundreds of costly and time-consuming fatigue experiments for each and every different loading case. The strain/stress ∼ life data are mostly related to push-pull type symmetric (R = −1) loading cases and the traditional Weibull probabilistic model are based on the associated end-of-life data. However, the Weibull approach doesn’t depend on the time evolution of damage but is just based on end-of-life data. It is our assumption that for a given loading and environment, the time-evolution based probabilistic risk assessment (PRA) and reliability model would produce more accurate results compared to a PRA model simply based on the end-of-life data obtained under a different loading conditions. However, the time-evolution based PRA for a particular loading and environment requires hundreds of fatigue tests, which might not always be possible to perform due to the high cost and time requirements. To overcome these issues, we propose the use of Markov-Chain-Monte-Carlo (MCMC) techniques for time series or time-evolution prediction of damage states under a particular loading and environment (e.g. in this case, high-temperature PWR coolant-water condition) condition. Then, the probabilistic fatigue life can be estimated on the basis of the simulated scatter band in damage states for a given failure criteria. In this paper, we discuss the MCMC model based probabilistic damage state estimation and associated probabilistic fatigue life of 316 stainless steel subjected to cyclic loading at 300 °C in-air and PWR-coolant-water conditions.
Multi-Scale Damage Analysis on Fatigue-Creep Process in Industrial Steel Structures
Authors: Guo Huajing , Li Zhaoxia 
Published: November 2019

Abstract
Fatigue-creep damage has been recognized as the elemental cause of failure of industrial steel structures exposed to high temperature. In order to better understand the degradation process, a previously developed multi-scale fatigue-creep damage is applied to evaluate the structural damage due to fatigue and creep process. In the model, the relationship between collective behavior of micro-cracks and fatigue damage variable was established and the nonlinear coupling of fatigue damage and creep damage was taken into consideration. Fatigue-creep damage analysis on a series of existing key connection shafts in industrial steel structures at high temperature are performed under different working condition and their lifetime are predicted based on the numerical calculation on the accumulated fatigue-creep damage up to structural failure. The numerical results indicate that the early stage of degeneration process is dominated by creep damage and the fatigue damage rate increases quickly at the later stage. The fatigue-creep lifetime of industrial steel structures varies significantly with different applied stress level and working temperature.
Fluid-Elastic Coefficients in Single Phase Cross Flow: Dimensional Analysis, Direct and Indirect Experimental Methods
Authors: Lagrange Romain , Piteau Philippe , Delaune Xavier , Antunes Jose 
Published: November 2019

Abstract
The importance of fluid-elastic forces in tube bundle vibrations can hardly be over-emphasized, in view of their damaging potential. In the last decades, advanced models for representing fluid-elastic coupling have therefore been developed by the community of the domain. Those models are nowadays embedded in the methodologies that are used on a regular basis by both steam generators providers and operators, in order to prevent the risk of a tube failure with adequate safety margins. From an R&D point of view however, the need still remains for more advanced models of fluid-elastic coupling, in order to fully decipher the physics underlying the observed phenomena. As a consequence, new experimental flow-coupling coefficients are also required to specifically feed and validate those more sophisticated models. Recent experiments performed at CEA-Saclay suggest that the fluid stiffness and damping coefficients depend on further dimensionless parameters beyond the reduced velocity.
In this work, the problem of data reduction is first revisited, in the light of dimensional analysis. For single-phase flows, it is underlined that the flow-coupling coefficients depend at least on two dimensionless parameters, namely the Reynolds number Re and the Stokes number Sk. Therefore, reducing the experimental data in terms of the compound dimensionless quantity Vr = Re/Sk necessarily leads to impoverish results, hence the data dispersion. In a second step, experimental data are presented using the dimensionless numbers Re and Sk. We report experiments, for a 3 × 5 square tube bundle subjected to water transverse flow. The bundle is rigid, except for the central tube which is mounted on a flexible suspension allowing for translation motions in the lift direction.
The evolutions of the flow-coupling coefficients with the flow velocity are determined using two different experimental procedures: (1) In the direct method, an harmonic motion of increasing frequency is imposed to the tube. (2) In the indirect method, the coefficients are obtained from the modal response of the tube (frequency, damping). The coefficient identification was performed well beyond the system instability boundary, by using active control, allowing an exploration of a significant range of flow velocity.
For a given Sk, the results show that: (a) at low Re, the flow-coupling coefficients are close to zero; (b) at intermediate Re, the flow stabilizes the tube; (c) at high Re, the flow destabilizes the tube, leading to a damping-controlled instability at a critical Re. Reducing the data in terms of Re and Sk clarifies the various experimental “branches”, which are mixed when using Vr. The two identification techniques lead to reasonably compatible fluid-elastic coefficients.
On Design and Analysis of Fastener Locking Tabs in Highly Chaotic Flow of Primary Side of Steam Generator
Authors: Ghafouri-Azar Reza , Stojakovic Mike 
Published: November 2019

Abstract
The primary side of steam generators has a divider plate which separates the heavy water entrance and exit of flow when entering in and out of the U-tubes of tubesheet. The divider plate has a series of plates which are connected by bolting. The bolted connections have positive locking device which prevents the connection from loosening in the highly vibrating turbulent flow conditions. These positive locking devices were failed by breaking into pieces at different occasions and a few cycle of design were completed to address this design failures. In the latest design modification a new design was proposed. The new design was applied to many steam generators. It has proven to be robust with respect to durability, strength and ease of installation. The new design has reduced outage time and activities. It is also reduces radiation exposure while improving conventional safety. The paper describes the design processes and addresses key design and analysis parameters. A Finite Element model was developed to facilitate assessment design calculation. Structural integrity of the newly design part was assessed against ASME Boiler and Pressure Vessel codes. A flow-induced vibration was completed to address fluid-structure interactions.
Susceptibility to Neutron Irradiation Embrittlement of Heat-Affected Zone of Reactor Pressure Vessel Steels
Authors: Takamizawa Hisashi , Katsuyama Jinya , Ha Yoosung , Tobita Tohru , Nishiyama Yutaka , Onizawa Kunio 
Published: November 2019

Abstract
The heat-affected zone (HAZ) of reactor pressure vessel (RPV) steels is known to show large scatter in Charpy impact properties because it has inhomogeneous microstructure due to thermal histories of multi-pass welding for butt-welded joints. The correlation between mechanical properties and microstructure such as grain size, phase-fraction, martensite-austenite constituent, on the characteristics of HAZ of un-irradiated materials was investigated. Neutron irradiation was conducted at Japanese Research Reactor −3 (JRR-3) operated by JAEA. The neutron irradiation susceptibility was evaluated based on post-irradiation examinations consisting of mechanical testing and microstructural analysis. In the experiments, typical RPV steel plate and their weldment were prepared. Simulated HAZ materials that have representative microstructures such as coarse-grain HAZ (CGHAZ) and fine-grain HAZ (FGHAZ) were also prepared based on the thermal histories calculated by finite element analysis. For un-irradiated materials, a part of simulated HAZ materials showed a higher reference temperature of the master curve method than that of the base metal (BM). The irradiation hardening of HAZ was almost the same or lower than that of the BM, and the shift of reference temperature for HAZ materials was comparable with that of BM.
Weld Residual Stress and Fracture Behavior of NASA Layered Pressure Vessels
Authors: Brust F. W. , Dodds R. H. , Hobbs J. , Stoltz B. , Wells D. 
Published: November 2019

Abstract
NASA has hundreds of non-code layered pressure vessel (LPV) tanks that hold various gases at pressure. Many of the NASA tanks were fabricated in the 1950s and 1960s and are still in use. An agency wide effort is in progress to assess the fitness for continued service of these vessels. Layered tanks typically consist of an inner liner/shell (often about 12.5 mm thick) with different layers of thinner shells surrounding the inner liner each with thickness of about 6.25-mm. The layers serve as crack arrestors for crack growth through the thickness. The number of thinner layers required depends on the thickness required for the complete vessel with most tanks having between 4 and 20 layers. Cylindrical layers are welded longitudinally with staggering so that the weld heat affected zones do not overlap. The built-up shells are then circumferentially welded together or welded to a header to complete the tank construction. This paper presents some initial results which consider weld residual stress and fracture assessment of some layered pressure vessels and is a small part of the much larger fitness for service evaluation of these tanks. This effort considers the effect of weld residual stresses on fracture for an inner layer longitudinal weld. All fabrication steps are modeled, and the high-level proof testing of the vessels has an important effect on the final WRS state. Finally, cracks are introduced, and service loading applied to determine the effects of WRS on fracture.
The Application of NUPACK to the Design of a Type B Packaging Containment Vessel
Authors: Karius Kathryn , Eberl Kurt R. , McKeel Charles A. , Abramczyk Glenn A. 
Published: November 2019

Abstract
The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Section III Division 3 (commonly referred to as NUPACK) was issued in 1997 to address the containments of nuclear transportation packagings. Previously, Section III consisted of only 2 divisions that address the construction of nuclear facility components: Division 1 for metal construction and Division 2 for concrete construction. Type B packagings have historically been designed to Division 1 standards. This paper discusses the application of NUPACK to the design of a Type B packaging containment vessel.
Fracture Mechanics Fatigue Evaluation of a Flowline Clamp Connector Using Finite Element Modeling of a Crack
Authors: Sifford Curtis , Shirani Ali 
Published: November 2019

Abstract
This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.
Numerical and Parameter Uncertainties: Are They Independent?
Authors: Eça Luís , Lopes Rui , Pereira Filipe Soares , Vaz Guilherme 
Published: November 2019

Abstract
In the Validation procedure proposed by the ASME V&V 20 Standard, the quantification of the modeling error of mathematical models solved by Computational Fluid Dynamics (CFD) requires the estimation of the experimental, numerical and parameter uncertainties. In its simplest form, these uncertainties are assumed independent. Parameter uncertainty is typically a consequence of lack of exact values for the boundary conditions and/or fluid properties. Its evaluation is handled by the broad field of uncertainty quantification. However, this evaluation requires simulations that are unavoidably affected by numerical errors. Therefore, it may be questionable if parameter and numerical uncertainties are really independent or, alternatively, how small must be the numerical uncertainty to estimate parameter uncertainties without its influence. In this paper we address the relation between parameter and numerical uncertainties using two test cases: the transition from laminar to turbulent flow on a flat plate at a Reynolds number of 107; the flow around the Eppler 387 airfoil at an angle of attack of 1o and Re = 3 × 105. The mathematical model for the three cases is the Reynolds-Averaged Navier-Stokes equations supplemented by the k–ω SST eddy-viscosity turbulence model and the one-equation γ transition model. Sensitivity coefficients are determined for the selected quantities of interest using the local sensitivity method and finite-differences. These estimates are performed for different levels of grid refinement to check its dependency on the estimated numerical error obtained from power series expansions. Results obtained in this study suggest that the evaluation of the parameter uncertainty only becomes independent of the numerical error when the simulation results are in the asymptotic range.
Bootstrapping and Jackknife Resampling to Improve Sparse-Sample UQ Methods for Tail Probability Estimation
Authors: Jekel Charles F. , Romero Vicente 
Published: November 2019

Abstract
Tolerance Interval Equivalent Normal (TI-EN) and Superdistribution (SD) sparse-sample uncertainty quantification (UQ) methods are used for conservative estimation of small tail probabilities. These methods are used to estimate the probability of a response laying beyond a specified threshold with limited data. The study focused on sparse-sample regimes ranging from N = 2 to 20 samples, because this is reflective of most experimental and some expensive computational situations. A tail probability magnitude of 10−4 was examined on four different distribution shapes, in order to be relevant for quantification of margins and uncertainty (QMU) problems that arise in risk and reliability analyses. In most cases the UQ methods were found to have optimal performance with a small number of samples, beyond which the performance deteriorated as samples were added. Using this observation, a generalized Jackknife resampling technique was developed to average many smaller subsamples. This improved the performance of the SD and TI-EN methods, specifically when a larger than optimal number of samples were available. A Complete Jackknifing technique, which considered all possible sub-sample combinations, was shown to perform better in most cases than an alternative Bootstrap resampling technique.