bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response Statistics of U-Oscillating Water Column Energy Harvesters Exposed to Extreme Storms: Application to the Case Study of Roccella Jonica (Italy)
Authors: Arena Felice , Laface Valentina , Malara Giovanni , Meduri Saveria , Pedroncini Andrea 
Published: December 2020

Abstract
This article deals with the case study of a marina located in Roccella Jonica (Italy), where a wave energy harvester belonging to the family of U-oscillating water columns (U-OWC) is going to be installed. U-OWCs are wave energy harvesters composed of a water column exposed to the action of random sea waves and an air pocket connected to the atmosphere by a power take—off (PTO) system. In Roccella Jonica, this device is going to be embedded in a vertical breakwater expanding the main layout of the infrastructure. For ensuring the structural safety of the system, to characterize statistically its response peaks in severe environmental conditions is important. In this context, one of the main difficulties is utilizing appropriate environmental conditions representing real extreme events at the installation site. This article proposes to adopt the DNV trapezoidal storm model for representing the time history of an extreme event in conjunction with a nonlinear U-OWC model. Relevant Monte Carlo simulations show that the DNV storm model provides peak distributions that are rather close to the ones obtained by processing real storm time histories. Thus, it can be adopted for checking the performance of the system in extreme conditions.
Deriving Design Feature Vectors for Patent Images Using Convolutional Neural Networks
Authors: Jiang Shuo , Luo Jianxi , Ruiz-Pava Guillermo , Hu Jie , Magee Christopher L. 
Published: December 2020

Abstract
The patent database is often used by designers to search for inspirational stimuli for innovative design opportunities because of the large size, extensive variety, and the massive quantity of design information contained in patent documents. Growing work on design-by-analogy has adopted various vectorization approaches for associating design documents. However, they only focused on text analysis and ignored visual information. Research in engineering design and cognitive psychology has shown that visual stimuli may benefit design ideation. In this study, we focus on visual design stimuli and automatically derive the vector space and the design feature vectors representing design images. The automatic vectorization approach uses a novel convolutional neural network architecture named Dual-Visual Geometry Group (VGG) aiming to accomplish two tasks: visual material-type prediction and international patent classification (IPC) section-label predictions. The derived feature vectors that embed both visual characteristics and technology-related knowledge can be potentially utilized to guide the retrieval and use of near-field and far-field design stimuli according to their vector distances. We report the accuracy of the training tasks and also use a case study to demonstrate the advantages of design image retrievals based on our model.
Analysis of the Postbuckling Response of Nonlocal Plates Via Fractional-Order Continuum Theory
Authors: Sidhardh Sai , Patnaik Sansit , Semperlotti Fabio 
Published: December 2020

Abstract
We present a comprehensive study on the postbuckling response of nonlocal structures performed by means of a frame-invariant fractional-order continuum theory to model the long-range (nonlocal) interactions. The use of fractional calculus facilitates an energy-based approach to nonlocal elasticity that plays a fundamental role in the present study. The underlying fractional framework enables mathematically, physically, and thermodynamically consistent integral-type constitutive models that, in contrast to the existing integer-order differential approaches, allow the nonlinear buckling and postbifurcation analyses of nonlocal structures. Furthermore, we present the first application of the Koiter’s asymptotic method to investigate postbifurcation branches of nonlocal structures. Finally, the theoretical framework is applied to study the postbuckling behavior of slender nonlocal plates. Both qualitative and quantitative analyses of the influence that long-range interactions bear on postbuckling response are undertaken. Numerical studies are carried out using a 2D fractional-order finite element method (f-FEM) modified to include a combination of the Newton–Raphson and a path-following arc-length iterative methods to solve the system of nonlinear algebraic equations that govern the equilibrium beyond the critical points. The present framework provides a general foundation to investigate the postbuckling response of potentially any type of nonlocal structure.
Fatigue Performance of Austenitic Stainless Steel: Enforced Endurance Limit and Questionable Design Curve
Authors: Solin Jussi , Seppänen Tommi , Mayinger Wolfgang 
Published: December 2020

Abstract
Design codes and standards are used for new designs and also for management of operation and in service inspection of existing NPP primary circuit pressure boundaries. The current codes — ASME, KTA, RCC-M, PNAE-G and JSME — have been originally rooted to the ASME Boiler and Pressure Vessel Code, Section III, Nuclear Vessels, which was published in 1963. Article 4, N-415 “Analysis for cyclic operation” instructed calculation of stress intensities for fatigue transients and provided two design curves for basic material types — one for ferritic, the other for austenitic steels.
The design curves were based on strain-controlled LCF tests, which measured the allowable numbers of cycles as function of plastic strain. The obtained material performance was then processed to strain-life and design curves (Sa = Ex εa). This local strain fatigue approach was found applicable for both ferritic and austenitic steels though their elastic plastic cyclic responses are much different. Fatigue data for stainless steels extended to ¼ million cycles and the design curve was extrapolated to one million cycles. Later on — supported by load-controlled HCF tests — the original LCF approach has been extended even beyond HCF to VHCF regime.
Our strain-controlled HCF results for alloy types 347 and 304L are in conflict with the reference mean curve behind current ASME curve for stainless steels. We assume that this reflects a generic issue related to extrapolation of the LCF methodology by Coffin, Langer and other pioneers. Furthermore, analysis of cyclic responses and variable amplitude testing to millions of cycles give reasons to assume that the concept of an endurance limit (Se) is applicable also for variable amplitude straining. Variable amplitude HCF straining was not studied for ferritic steels and we propose the concept of enforced endurance limit to austenitic stainless steels only.
We propose a critical review on relevance of the current ASME III design curve for stainless steels.
Residual-Stress, Material Characterization in P22 HRSG-Pipeline Butt Joint
Authors: Grisolia Ottaviano , Scano Lorenzo , Piccini Francesco , Lo Conte Antonietta , De Agostinis Massimiliano , Fini Stefano 
Published: December 2020

Abstract
Previous study evaluated residual stress in a circumferential “V”-groove butt joint of a heat-recovery steam generator (HRSG) pipeline; the material was ASTM A-335-Grade P22. Aim had been to check on the influence over creep-relaxation previously found out for a tee made of the same material. The butt joint had been operating for the same period of 200,000 hours, same temperature of 528°C at almost a half pressure (0.46 Kg/mm2 vs. 1.06 Kg/mm2). X-ray diffraction (XRD) technique applied close to the weld highlighted anomalously high stress-level on the outer surface for all four butt-joint samples tested. Residual-stress over 400 MPa observed along the cylinder’s tangential direction was statically not acceptable. On the inner surface where deposited beads may have tempered adjacent base material, measurement via blind hole-drilling (BHD) technique showed a symmetrical plane-state residual-stress of 199 MPa. It was consistent with that observed via XRD on the outer surface in the cylinder’s longitudinal direction. Supposing a case of incomplete post heating planned for the weld may have explained the occurrence of being much higher than 40 MPa, value predicted after 200,000 hours. Similar influence over creep results found out for the tee and the butt joint had validated modeling welding simulation considered for both joints. A comprehensive new series of XRD tests aims now at measuring residual stress across the cylinder’s wall, both inner and outer sides. The shallow layer considered has thickness sufficient for building a map of measurements covering different depths and locations on the surface. The experimental plan includes also BHD tests supporting the XRD ones. Comparison with previous measurements roughly shows stress level increasing similarly across the cylinder’s wall from the inner side on: Average stress values, however, appear lower than previous measurements, showing better compatibility to the analysis results.
Predicting Pipe Rupture Frequencies Using xLPR
Authors: Rudland David L. 
Published: December 2020

Abstract
Over the last several years, the U.S. Nuclear Regulatory Commission (NRC), in cooperation with the Electric Power Research Institute (EPRI), conducted a multi-year project that focused on the development of a viable method and approach to address the effects of primary water stress corrosion cracking (PWSCC) in primary piping systems approved for leak-before-break (LBB). This project, called eXtremely Low Probability of Rupture (xLPR), defined the requirements necessary for a modular-based probabilistic fracture mechanics assessment tool to directly assess compliance with the regulations. Version 2.0 of this code has been completed and is currently awaiting public release.
Since the focus of xLPR Version 2.0 is investigating the impacts of active piping degradation on the leak-before-break behavior of reactor coolant piping, questions have been raised to whether xLPR can be used to confirm pipe rupture frequencies developed in other efforts, such as NUREG-1829, “Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process.” This paper discusses an initial study focused on whether xLPR can be used to estimate pipe rupture frequencies.
A series of analyses were conducted, based on inputs developed by the xLPR program team, focused on the reactor pressure vessel outlet nozzle geometry of a typical pressurized water reactor. Additional analyses were conducted using the same radius-to-thickness ratio but decreasing the pipe diameter. Due to computer memory restrictions, it was difficult calculating low probability events when considering PWSCC initiation, typical residual stresses, leak detection and in-service inspection. Therefore, to bound the problem, an aggressive weld residual stress was assumed with multiple pre-existing defects. By modifying the size and number of these initial defects, results were generated that indicated the conditional probability of rupture was related to the percentage of the inner circumference cracked and the pipe diameter.
Using the PWSCC initiation model from xLPR Version 2, the yearly rupture frequency with leak detection and in-service inspection was calculated. The results indicate that the rupture frequencies in NUREG-1829 appear conservative relative to the results from this study.
Due to the limited scope of this study, the assumptions used in these analyses were limited or conservative; therefore, additional analyses are needed for a more robust comparison. However, the results suggest that conducting xLPR analyses with pre-existing defects may be useful in bounding LBB applicability with active degradation.
Introduction of the Technical Document in Japan for Safety Use of Type2 Pressure Vessels in Hydrogen Refueling Stations
Authors: Sato Shinya , Kobayashi Hiroshi , Fukimoto Hajime , Maeda Shigeru , Yoshikawa Nobuhiro , Arashima Hironobu 
Published: December 2020

Abstract
We considered the Type2 pressure vessel (hereinafter, Type2) used in hydrogen refueling stations (hereinafter, HRS), a stational Composite Reinforced Pressure Vessel (hereinafter, CRPV) in which a metal layer made of high-strength low-alloy steel is wrapped with a carbon fiber reinforced plastic (hereinafter, CFRP) layer in the circumferential direction. Because Type2 is lightweight and has a long life, installation in HRS is expected. However, since no technical standards concerning design for safe use of Type2 for HRS currently exist, few Type2 have been installed in HRS in Japan.
Based on these circumstances, we are developing a Technical Document on the safe use of Type2 (hereinafter, TD) to promote the installation of Type2 at HRS.
In this paper, we introduce the current discussion on issuance of the TD as an industrial standard, focusing especially on the following: Type2 shall be considered a two-layer pressure vessel in which the CFRP layer shares the circumferential stress of the metal layer. The wall thicknesses of the metal layer and CFRP layer of Type2 are calculated by Design by Rule approach, but when necessary, Design by Analysis (stress analysis and fatigue analysis) can be applied. Design specification tests such as the burst test and hydraulic pressure cycle test using an actual Type2 should not be required. The hydrogen compatibility and fatigue life of the low-alloy steel used in the metal layer are evaluated in accordance with our previously-proposed methods [1]. In the fatigue analysis, the effect of autofrettage can be considered.
Study on Numerical Simulation of Gas-Solid Erosion for Horizontal Feed Pipe
Authors: Hu Weiwei , Hu Lichen , Sun Li , Shen Chengye , Chen Hu 
Published: December 2020

Abstract
The gas-solid two phase flow was formed in the catalyst conveying pipeline with the catalyst particles coming from the top of the inclined pipes and air blowing from one side of the horizontal feed pipe. The upper side of horizontal pipe was seriously eroded. The erosion situation of feed pipe was simulated by the Discrete Phase Model (DPM) in Fluent software. The simulation result was compared with the field pipeline, and the gullies on the upper side of the horizontal pipe were formed by the particles concentrating on the upper side of the horizontal pipe with the excessive gas phase velocity. The reasonable distribution method of velocity was put forward by grouping numerical simulation of different particle velocities and blowing velocities. The particles were remained in the intermediate position of the horizontal pipe to reduce the collision between particles and the pipe wall. Therefore, the erosion rate of the pipe was slowed down; in addition, the service life of pipeline was prolonged. The research results of this paper could be used to provide reasonable feed speed for the actual petrochemical feed pipe. The protection methods was put forward for the horizontal feed pipe. The safety of petrochemical enterprises were guaranteed.
Post-Irradiation Evaluation of Eurofer97 Fracture Toughness Using Miniature Multinotch Bend Bar Specimens
Authors: Chen Xiang , Clowers Logan A. , Graening Tim , Bhattacharya Arunodaya , Campbell Anne A. , Robertson Janet , Geringer Josina W. , Sokolov Mikhail A. , Katoh Yutai , Rieth Michael 
Published: December 2020

Abstract
In this study, we performed fracture toughness characterization of ten neutron-irradiated Eurofer97 variants using precracked miniature multi-notch bend bar (M4CVN) specimens based on the Master Curve method in the ASTM E1921 standard. The neutron irradiation was performed in the flux trap position of the High Flux Isotope Reactor (HFIR) of the Oak Ridge National Laboratory (ORNL) with the nominal irradiation temperature of 300°C and irradiation dose of 2.5 displacements per atom (dpa). Depending on the irradiation temperature and materials, we observed different degrees of irradiation hardening and embrittlement for ten Eurofer97 variants. The upper shift in the Master Curve reference temperature T0Q vs. the increase in Vickers microhardness values showed a liner relationship for only a few materials indicating different irradiation responses of the Eurofer97 variants.
Current Situation and Prospect of Underground Gas Storage Well
Authors: Shi Kun , Duan Zhixiang 
Published: December 2020

Abstract
Gas storage well (GSW) is a sort of pressure vessel and a typical model of underground pressure vessel. Now the media of GSW is mainly compressed natural gas (CNG). The main advantages of GSW are analyzed, such as safety and economy are discussed. The current application field and the potential application field of GSW are also explained. Since the idea of GSW originated from oil-gas engineering, GSW has the absolute merit as well as connatural deficiency comparing to the conventional pressure vessel. The problems on material, design, manufacture, inspection, etc. of GSW based on current situation are discussed, forward analysis and expectation for its prospect are brought.
With the idea of GSW, some special type underground pressure vessel appeared, such as the underground cylinder type pressure vessel. The structure, design, manufacture of the underground cylinder type pressure vessel is discussed. With the development of new energy, the application field of the GSW is gradually expanded. The hydrogen storage GSW (HGSW) comes into being. The advantage such as safety and economy of HGSW, and the disadvantage are also analyzed. The key questions for the HGSW used in the hydrogenation fueling station are also summarized. The solution for material-hydrogen compatibility and tightness of high pressure HGSW is discussed finally.
A Historical Overview of Design Analyses and Experimental Observations of Ratcheting Phenomenon
Authors: Macedo Jean , Chapuliot Stéphane , Bergheau Jean-Michel , Feulvarch Eric , Ancelet Olivier , Martin Antoine 
Published: December 2020

Abstract
In order to investigate the ratcheting behavior and to determine new design rules, some experimental tests were conducted in many countries in the last decades. In France, some tests were carried out under mechanical or thermal cyclic loading to examine this risk. The first section of the current article is addressed to the state of the art concerning the ratcheting effects. The difference between Local and Global Ratcheting is clarified. The second section is dedicated to the experimental observations of ratcheting. The following section describes the constitutive models which are able to simulate material/structural ratcheting responses. The models presented are Linear Kinematic, Armstrong-Frederick, Chaboche, Ohno-Wang and Chen-Jiao-Kim. Finally, the ratcheting rules in design codes are exposed. Both simple and complex rules are presented.
Comparative Study on Different National Standards for Local Post Weld Heat Treatment of Pressure Vessels
Authors: Ji Fang , Deng Guide , Duan Linlin , Liu Cenfan , Zhao Xiaonan 
Published: December 2020

Abstract
In order to eliminate these welding residual stress which produced in the process of pressure vessel manufacturing and assembling, post-weld heat treatment is required for the weld structure. The Large size and complex structure pressure vessel which cannot integral post-welding heat treatment always implement local post-welding heat treatment. The reasonable heated band and insulated band are particularly important in the procedures of local post-welding heat treatment to meet the requirements of pressure vessel heat treatment. The recommended heated band and insulated band are given in different national standards. But the recommended width of heated band and insulated band are different in different national standards. In the paper, numerical simulation was carried out to compare and study the difference of temperature distribution in the holding temperature period when post-welding heat treatment of pressure vessel barrel butt weld. The result show that the temperature distribution on sock band is very closed when the barrel butt weld implements post weld heat treatment with the heated and insulated band recommended in ASME BPVC-VIII-2017 and EN 13445-4:2014. The axial temperature gradient on sock band is very small and the temperature difference almost comes from the temperature difference through the thickness. Compared with this, the axial temperature gradient is larger and the temperature difference through thickness is smaller when post weld heat treatment with the max recommended heated and insulated band given in GB/T 30583-2014.
Assessment of Flaw Interaction Under Combined Tensile and Bending Stresses: Suitability of ASME Code Case N877-1
Authors: Dulieu Pierre , Lacroix Valéry , Hasegawa Kunio 
Published: December 2020

Abstract
In the case of planar flaws detected in pressure components, flaw characterization plays a major role in the flaw acceptability assessment. When the detected flaws are in close proximity, proximity rules given in the Fitness-for-Service (FFS) Codes require to combine the interacting flaws into a single flaw. ASME Code Case N877-1 provides alternative proximity rules for multiple radially oriented planar flaws. These rules are applicable for large thickness components and account for the influence of flaw aspect ratio. They cover the interaction between surface flaws, between subsurface flaws and between a surface flaw and a subsurface flaw. The calculations of flaw interaction have been performed under pure membrane stress. However, actual loading conditions induce non-uniform stresses in the component thickness direction, such as thermal bending or welding residual stresses. Non-uniform stress fields can lead to variations in the Stress Intensity Factors of closely spaced flaws, affecting their mutual interaction. The objective of this paper is to assess the suitability of ASME Code Case N877-1 with regards to the presence of a bending part in the applied stress distribution. For that purpose, various applied stress profiles and flaw configurations are covered. The effect on flaw interaction is assessed through three-dimensional XFEM analyses.
A High Temperature Primary Load Design Method Based on Elastic Perfectly-Plastic and Simplified Inelastic Analysis
Authors: Messner M. C. , Jetter R. I. , Sham T.-L. 
Published: December 2020

Abstract
The current primary load design provisions of Section III, Division 5 of the ASME Boiler and Pressure Vessel Code, covering high temperature nuclear components, represent an allowable stress methodology using elastic analysis and stress classification procedures to approximate stress redistribution caused by creep and plasticity. This process is difficult to implement and automate in modern finite element frameworks. This paper describes an alternate primary load design approach that uses elastic perfectly-plastic analysis in conjunction with the reference stress concept to eliminate stress classification while retaining a link to the existing Section III, Division 5 allowable stresses. This global, structural allowable stress check is supplemented with a local check to guard against the initiation of creep damage at local stress discontinuities like headers, nozzles, and other stress concentrations. This check is based on a simple elastic-creep analysis with creep damage calculated with the time-fraction approach, using the current ASME minimum-stress-to-rupture values already provided in the current Code. Both the global and local checks are easily implemented in modern finite element analysis software and greatly simplify Section III, Division 5 primary load design when compared to the current design-by-elastic-analysis method. Several examples demonstrate the utility of the new approach and its potential to reduce over-conservatism.