bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling a Spent Nuclear Fuel Cask Seismic Test
Authors: Klymyshyn Nicholas , Kadooka Kevin , Fitzpatrick James , Spitz Casey 
Published: November 2023

Abstract
The US Department of Energy Spent Fuel and Waste Science and Technology (SFWST) program is planning to conduct a series of full-scale shake table tests to simulate hypothetical earthquake conditions and record the response of surrogate spent nuclear fuel (SNF) assemblies in a canister dry storage system mockup. The shake table motions will represent a range of hypothetical earthquake conditions at hypothetical locations in the continental US to generally define the range of mechanical loads that SNF can be expected to experience during extended dry storage periods. The earthquake conditions will represent seismic hazards in the 2,000-to-20,000-year return period range.
The test will use instrumented pressurized water reactor (PWR) fuel assemblies with surrogate mass inside the fuel rods instead of radioactive fuel pellets. Dummy assemblies with similar mass and dimensions to actual fuel assemblies will occupy the rest of the fuel assembly locations in a SNF canister that holds 32 fuel assemblies. The canister will be located inside a mockup vertical concrete cask (VCC). Instrumentation will record the motion of the major components of the complex dynamic system, and strain gauges will be used to record the cladding strain at selected locations. Preparations for the test require modeling predictions to identify the range of response of the system and to help select specific earthquake ground motion cases to be simulated on the shake table from a larger set of potential cases.
This paper describes the pretest nonlinear finite element modeling efforts that have been completed to date, including cask system level modeling and fuel assembly modeling in LS-DYNA. The cask system level models are critical for anticipating sliding or tipping of an unanchored cask during the test. The fuel assembly model is needed to estimate the range of cladding strain response and fuel assembly structural response to be expected during the test and cladding strain measurements will be key metrics for model validation and the development of modeling best practices after the test is concluded.
Investigation on Buckling Instability Behavior Mechanism of Rubber Balloon of Bladder Accumulator of Cavity Pressure
Authors: Ni Tianyv , Wang Bo , Duan Chenghong 
Published: November 2023

Abstract
Bladder accumulator is a common buffer element in hydraulic oil circuits, it would abnormally deform during decompression on occasion, resulting in a liquid-trapped phenomenon. In order to investigate the mechanism of this unusual phenomenon, firstly, an experimental study focused on the deformation state of the rubber balloon of bladder accumulator was conducted. Secondly, according to the actual working load conditions of the bladde accumulator, a self-compiled VDLOAD user subroutine was used for loading, and the nonlinear post-buckling analysis of the rubber balloon was performed by displacement perturbation method based on the buckling mode. Finally, influences of the pressure in the balloon cavity on the post-buckling deformation of the rubber balloon were explored. The results show that the oil-trapped deformation of the rubber balloon experiment is in good agreement with the post-buckling analyzed deformation state. It is concluded that the oil-trapped phenomenon of the bladde accumulator is due to the buckling instability deformation of three pits on the premise of the uniform hydraulic distribution. In addition, the gas pressure in the balloon cavity affects the post-buckling deformation mode of the rubber balloon. Within the design pressure range, the oil-trapped phenomenon can be avoided by reducing the pressure in the rubber balloon cavity.
Microstructure Characterization of EU INCEFA-SCALE 316L Stainless Steel Fatigue Specimens – Mechanistic Understanding
Authors: Vainionpää Aleks , Spadotto Julio , Que Zaiqing , Connolly Brian , Mclennan Alec , Arrieta Sergio , Huret Joseph , Damiani Thomas 
Published: November 2023

Abstract
A pressurized water reactor (PWR) primary environment can have a deleterious effect on the fatigue lifetime of austenitic stainless steels. One of the main goals of a five-year INCEFA-SCALE (INcreasing safety in NPPs by Covering gaps in Environmental Fatigue Assessment — focusing on gaps between laboratory data and component SCALE) project, kicked off in October 2020 and supported by the European Commission HORIZON2020 programme, is to develop an improved mechanistic understanding behind the effect of a PWR primary environment on the fatigue behavior of austenitic stainless steels through coordinated extensive characterization of as-machined and tested specimens at partner organizations.
This work focuses on the microstructure characterization of as-received austenitic stainless steel 316L plate material and as-machined fatigue specimens, as well as the preparation of guidelines on post-mortem characterization for the consortium. The presented microstructure characterization is carried out using light optical microscopy (LOM), scanning electron microscopy (SEM), and analytical electron microscopy (AEM) (including electron backscatter diffraction (EBSD), scanning/transmission electron microscopy (STEM/TEM), X-ray energy dispersive spectroscopy (EDS) and electron diffraction). The hardness, grain structure, inclusions, and delta-ferrite of the as-received 316L material were investigated. The surface roughness, machining-induced deformation layers, and ultra-fine-grained structure of as-machined ground and polished specimens were studied.
A ground surface finish leads to significantly higher machining-induced deformation, and surface roughness, with plenty of machining-induced cracks and defects extending a few microns into the bulk material, compared to a polished finish. The guidelines on the post-mortem characterization for the whole consortium can guide partner organizations in their posttest analysis for a direct comparison of the characterization data, which facilitates the mechanism interpretation.
Feasibility and Optimization of Nozzle Flapper System for Position Measurements of High-Speed Rotation Spindle With Aerostatic Bearings
Authors: Xu Peimin , Inaba Kazuaki , Takeishi Hisami , Kagawa Toshiharu 
Published: November 2023

Abstract
In recent years, due to the increased demand for semiconductors, there has been a need to increase the rotation speed and load of processing spindles. Spindles with aerostatic bearings were proposed as a solution to the above needs but lacked an effective position measurement as part of a compensation strategy. In this paper, measurements for spindle position control using the nozzle flapper system are proposed and verified through experiments under the rotation speed of 20,000 rpm. The individual and interactive influence of the multi-fluid structures, such as orifices, nozzle, and condition parameter supply pressure on the relation between the distance from the nozzle to the rotating body and the control pressure was experimentally studied. Meanwhile, securing static and dynamic characteristics is challenging because the distance between the shaft and the outer cylinder is small. This paper proposed a multi-hole nozzle system and conducted its static and dynamic characteristic tests in this case. In addition, the influence of the volume of the control room on the frequency response of the nozzle flapper system was discussed theoretically, and experiments verified the conclusion. This research can provide the design and optimization method of the nozzle flapper system for the high-speed rotation spindle position measurement and further study.
Sensitivity of Residual Stresses due to the Implementation of Local Post Welding Thermal Stress Relieving
Authors: Billon François , Willaume Pierre , Miguet Anthony , Moreau François 
Published: November 2023

Abstract
This study deals with an industrial case which consists in the Post Weld Heat Treatment (PWHT) of a butt weld of two shells of large diameter, high thickness and great length constituting parts of pressure equipment.
The limited local heated length is the source of local thermal gradients in the longitudinal direction because of the existence of transitions between hot and cold parts at the ends of the heated zones. These local thermal gradients generate residual stresses which are distributed in the so called “Heated Zone”, including the zone of the weld to be relieved named “Soak Band”, but also in the transition zones on either side of the heated zone, which we refer to as the “Gradient Control Band”.
The stress relief being carried out at a keeping average temperature of 615°C and according to a well-defined thermal cycle in time (heating and cooling rate and keeping duration), the evolution of the thermomechanical stresses due to the thermal cycle is calculated using a combination of the laws of plasticity and creep of the material of low alloy type 16MND5.
The plasticity and creep laws being fixed, and the residual stresses being determined for a reference heating configuration, the effect on the residual stresses of a simple variation in the extent of the thermal insulated zones are evaluated.
Flange Design Factors for the ASME BPVC Over Extended Parameter Ranges
Authors: van Zyl Gys , Francis Daniel , Ruffin Mark 
Published: November 2023

Abstract
The design of bolted flange joints according to the ASME BPVC uses the Taylor Forge method, first published in 1949. This method uses geometric factors (F, V and f for integral flanges and FL and VL for loose flanges) in the calculation of stresses in a tapered hub flange. The ASME BPVC, Section VIII, Division 1 provides charts and equations that can be used to calculate the factors. The charts are provided over a range of hub thickness ratios (g1/g0) from 1 to 5, and for hub length parameters (h/h0) between 0 and 2. Section VIII, Division 2 uses the same factors, but provides a different set of equations to calculate the factors. Within the parameter ranges of the Division 1 charts, the Division 1 and Division 2 equations give essentially the same results, but the methods diverge for parameters outside the chart ranges. This paper will describe the origin of the geometric factor curves and problems that arise when using the Division 1 and Division 2 flange design factor equations outside the parameter ranges of the Division 1 charts. New equations for the flange design factors that are valid over extended parameter ranges were derived from the original closed-form solution of the tapered hub flange and are proposed as an improvement to the current equations used in ASME Section VIII, Division 1 and Division 2.
Defect Recognition and Classification From Ultrasonic Phased Array Total Focusing Method Imaging Based on Random Forest
Authors: Wang Haibin , Fan Zhichao , Chen Xuedong , Cheng Jingwei , Chen Wei , Wang Zhe , Bu Yangguang 
Published: November 2023

Abstract
Pipeline transportation is one of the principal energy transportation methods. The safety performance of pipelines in construction and operation is closely related to the quality of welds. If the pipeline weld defects cannot be accurately identified promptly, late maintenance may cause leakage arising from the welding defects, which will give rise to considerably serious consequences. Ultrasonic phased array inspection is a widely used technology in non-destructive testing, which can significantly improve the sensitivity, coverage and accuracy of detection. In particular, the development of total focusing method imaging can obtain high-resolution images of cracks and other weld defects in pipeline. At the moment, imaging results necessitate manual judgment of defect type, which is highly dependent on the prior knowledge of the inspector. This leads to measurable amount of misjudgment, especially for the longdistance pipeline defect detection in which the amount of detection data is large and the imaging features are difficult to be recognized. Consequently, the automated recognition and classification of the defects is the emerging approach to resolve those. This study focuses on the linear defects and volumetric defects in welds (i.e. cracks and pores). Typical test blocks containing defects are fabricated and an ultrasonic phased array is employed to generate the images of the defects by using total focusing method (TFM) algorithm. To expand the sample size for small number of TFM results, the data augmentation approach is proposed and implemented. Then, the extracted features are input into the random forest algorithm, followed by debugging and optimization. The results suggest that the recognition and classification of defects from images are realized, and the accuracy rate of defect recognition is 96%.
Proposal of Performance-Based Seismic Fragility Concept Related to Failure Modes for a Piping System
Authors: Mano Akihiro , Sato Takuya , Ichimiya Masakazu , Kasahara Naoto 
Published: November 2023

Abstract
After the Great East Japan earthquake, the countermeasures for beyond design basis events (BDBEs) have become more important. For a component, mitigation of a consequence of a failure in terms of impact on safety performance is required in addition to prevention of the failure. One of the key issues regarding BDBE is a structural failure of a piping system subjected to excessive earthquakes. The piping systems have various kinds of failure modes such as collapse, break, ratchet deformation and fatigue. Collapse and break can lead to significance degradation of core cooling performance. On the other hand, small deformation or fatigue clack have small impact on the cooling performance. However, the existing seismic fragility does not take into account the failure consequence and its dependency on failure modes. In this paper, we propose a new concept regarding performance-based seismic fragility for BDBEs by including failure consequence. In the concept, the core cooling performance is taken as the most important safety performance. The performance degradation is evaluated as failure consequence considering the dependency on the failure modes by the following approaches. As for collapse, the approach differs by the existence of a crack in the piping system. In case a crack is not included, the large deformation is estimated to occur in the piping. Based on the deformation, change in geometry of a flow channel of coolant is estimated. Considering the flow channel, change in a flow rate is estimated. Finally, the performance degradation by the flow rate change is evaluated. On the other hand, in case a crack is included, a break of the piping and a leak from the break point can occur. Based on the break size, a leak rate and change in flow rate is estimated. Finally, the performance degradation based on the flow rate change is evaluated. As for ratchet, deformation of the piping due to an earthquake is estimated. Based on the deformation, the performance degradation is evaluated by the same approach as the collapse of piping with no cracks. As for fatigue, the size of a through-wall crack initiated by an earthquake is estimated. Based on the crack size, the performance degradation is evaluated by the same approach as the collapse of piping with a crack.
Application of Code Cases 2951 and 2964 for Elevated Temperature Design of Pressure Vessels Considering Load Durations
Authors: Kagita Gurumurthy , Addala Mahesh Babu , Krishna Pottem Penchala Sai , Srinivasan Balaji , Pudipeddi Krishnakant Venkat , V. R. Sripada Subramanyam 
Published: November 2023

Abstract
The rules of ASME B&PV Section VIII Code provide (i) allowable tensile stress at elevated temperatures based on time duration of 100,000 hours; (ii) external pressure charts which do not account for reduction of buckling strength due to creep under short or long-term loads. For short term operating conditions for which component design governed by an allowable tensile stress based on long term (100,000 hours) creep properties is unrealistically conservative and may be non-conservative in the case of very long load durations (&gt; 100,000 hours). At elevated temperatures, the allowable compressive stress depends on magnitude of load and duration. The newly released code cases, Case 2951 ‘Alternative Approach for Operating Conditions (Including Occasional Loads) in the Time-Dependent Regime’ and Case 2964 ‘Allowable Compressive Stress in the Time-Dependent Regime’ provide procedures for elevated temperature design of pressure vessels considering load durations. In this paper, for successful implementation of these code cases, the key variables are reviewed and the inherent assumptions made in the development of these code cases are highlighted. Also, the code cases are applied for design of typical pressure vessel components and the results are compared with other relevant procedures which consider load duration into account.
Development of Stress Intensity Factor Solution for Surface Crack at Nozzle Corner in Reactor Pressure Vessel
Authors: Yamaguchi Yoshihito , Takamizawa Hisashi , Katsuyama Jinya , Li Yinsheng 
Published: November 2023

Abstract
The stress intensity factor (SIF) for a crack at nozzle corner is a key parameter in the structural integrity assessment of nozzle in a reactor pressure vessel (RPV). Although various SIF solutions for surface cracks at nozzle corners have been proposed, most focus only on the deepest point of the crack, and the information about geometric dimension of the nozzle corner is not clear. According to previous fatigue test results regarding the surface crack at the nozzle corner, the amounts of crack growth at the surface points were larger than that at the deepest point of the crack. Such results imply that SIFs at the surface points may be higher than that at the deepest point. It is necessary to provide SIF solutions for both surface and deepest points to increase the reliability of the structural integrity assessment. Through finite element analyses, this study developed SIF solutions for two surface points and the deepest point of a surface crack at the nozzle corners. The solutions correspond to the geometric dimensions of the nozzle corner and crack size.
Tribological Behaviour in the Underhead for High Strength Socket-Head Screws Coupled With Cast Iron and Tightened in Dry and Lubricated Condition
Authors: Croccolo Dario , De Agostinis Massimiliano , Fini Stefano , Olmi Giorgio , Scapecchi Chiara , Vincenzi Nicolò 
Published: November 2023

Abstract
The present paper investigates the influence of several design parameters on the frictional response at the underhead in a bolted joint, involving high strength socket-head screws: M8 class 14.9 with black oxidization coating. The experimentation deals with an underhead materials (Cast iron), lubrication conditions (dry, lubricated) and repeated tightening operations. The awareness of the actual friction coefficients, depending on the current operating parameters, is a useful tool, to support the most proper design of a bolted joint. The experimental campaign has been run by a testing rig for friction coefficient estimation, complying with the recommendations by International Standard ISO 16047 and the automotive Standard VW01131-1 in order to consider the effect of the tightening speed normally adopted in the automotive field. The axial preload generated upon tightening induces a high pressure on the remarkably small underhead surface of the utilized high strength socket-head screws and is therefore likely to affect the tribological response. Consequently, some differences may be expected with respect to the tribological behaviour of screws belonging to lower strength grades. This is particularly true, when tightening is done without bearing lubrication, and through several repeated assembly-disassembly operations. The collected data have been processed by the tools of ANOVA and F-Test, in order to assess the significance of each factor, as well as related interactions.
Investigations on Vibroacoustic Characteristics of Sandwich Plates With Viscoelastic Core Using Coupled FE-BE Method
Authors: Ji Ming , Sekiguchi Yu , Naito Masanobu , Sato Chiaki 
Published: November 2023

Abstract
The car body panel gets thinner as automotive lightweight technology advances, which affects NVH performance. To achieve the desired noise control, both radiation and propagation paths should be taken into consideration. It is suggested that Passive Constrained Layer Damping (PCLD) can be used to address the problems. In order to efficiently assess the acoustic vibration properties of a sandwich plate with a viscoelastic core, the coupled finite element and boundary element (FE-BE) method is used. The four-node plate element is used to simulate the plate. The direct boundary method is used to solve the Helmholtz wave equation for air. The coupled FE-BE method is used to calculate the radiated sound field under point excitation. The sandwich plate is made of two aluminum plates bonded by structural adhesive. The dynamic mechanical parameters of the adhesive are obtained by the modified Oberst method, which uses a composite beam with an aluminum base beam and a layer of adhesive. Then, the master curve is applied in the coupled FE-BE procedure. The acoustic pressure is measured by a microphone when an impact hammer hits a sandwich plate. Comparisons with both impact tests and the proposed FE-BE method are shown to prove the accuracy and computational efficiency for the modeling of the vibro-acoustic response of the viscoelastic sandwich plates.
Experimental Study of Combined Effects of Liquid-Solid Flow Erosion and Alkaline Acid Water Corrosion in Coal Water Slurry Gasification Unit
Authors: He Meng , Chen Sheng , Sun Li , Kang Haoyuan , Han Zhiyuan , Xie Guoshan 
Published: November 2023

Abstract
The combined effect of liquid-solid erosion and alkaline acid water corrosion (mainly NH4HS corrosion) always speed up wall thinning, punching, even breaking up leading to dangerous medium leakage and shorting the running period of coal water slurry gasification units. Comparison with three experimental date sets involving deionized water, NH4HS and deionized water, and particles and NH4HS solution are conducted in terms of loss weight amounts of SA106 Gr.B steel. This work aims to investigate the thinning damage rule under the combined effect of pulverized coal particle erosion and NH4HS solution corrosion, furthermore, a novel reduction rate prediction model including some key factors of NH4HS and particle concentrations and flow velocity is proposed to guide erosion shield for coal water slurry gasification units. The results show that the particle concentration has a small effect on particle erosion at a low liquid-solid flow velocity (3m/s). There is a shield effect on the reduction rate near wall until to 6% of particle concentration, therefore, flow velocity plays a dominant role for erosion at 6% of particle concentration. With the increase of NH4HS concentration or flow velocity, the erosion rate increases gradually. The particle concentration has less emphasis on the reduction rate than NH4HS concentration or flow velocity. Higher particle concentration is beneficial for avoiding the damage of corrosion films, and then inhibits eroding from NH4HS solution.